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  • Optimizing division/exponential calculation

    - by Saltheart
    I've inherited a Visual Studio/VB.Net numerical simulation project that has a likely inefficient calculation. Profiling indicates that the function is called a lot (1 million times plus) and spends about 50% of the overall calculation within this function. Here is the problematic portion Result = (A * (E ^ C)) / (D ^ C * B) (where A-C are local double variables and D & E global double variables) Result is then compared to a threshold which might have additional improvements as well, but I'll leave them another day any thoughts or help would be appreciated Steve

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  • Boost MultiIndex - objects or pointers (and how to use them?)?

    - by Sarah
    I'm programming an agent-based simulation and have decided that Boost's MultiIndex is probably the most efficient container for my agents. I'm not a professional programmer, and my background is very spotty. I've two questions: Is it better to have the container contain the agents (of class Host) themselves, or is it more efficient for the container to hold Host *? Hosts will sometimes be deleted from memory (that's my plan, anyway... need to read up on new and delete). Hosts' private variables will get updated occasionally, which I hope to do through the modify function in MultiIndex. There will be no other copies of Hosts in the simulation, i.e., they will not be used in any other containers. If I use pointers to Hosts, how do I set up the key extraction properly? My code below doesn't compile. // main.cpp - ATTEMPTED POINTER VERSION ... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/tokenizer.hpp> typedef multi_index_container< Host *, indexed_by< // hash by Host::id hashed_unique< BOOST_MULTI_INDEX_MEM_FUN(Host,int,Host::getID) > // arg errors here > // end indexed_by > HostContainer; ... int main() { ... HostContainer testHosts; Host * newHostPtr; newHostPtr = new Host( t, DOB, idCtr, 0, currentEvents ); testHosts.insert( newHostPtr ); ... } I can't find a precisely analogous example in the Boost documentation, and my knowledge of C++ syntax is still very weak. The code does appear to work when I replace all the pointer references with the class objects themselves. As best I can read it, the Boost documentation (see summary table at bottom) implies I should be able to use member functions with pointer elements.

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  • "The server closed the connection without sending any data"

    - by Toby
    Server setup The problem Diagnostic information What I've tried Specific Help needed 1. I have the following server setup: Debian Squeeze Linux 2.6.32-5-amd64 Apache2-mpm-prefork 2.2.16-6+squeeze10 PHP 5.3.3-7+squeeze14 This server is protected with the Suhosin Patch 0.9.9.1 Max Requests Per Child: 0 - Keep Alive: on - Max Per Connection: 100 Timeouts Connection: 300 - Keep-Alive: 15 Loaded Modules core mod_log_config mod_logio prefork http_core mod_so mod_alias mod_auth_basic mod_auth_digest mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_cgi mod_deflate mod_dir mod_env mod_mime mod_negotiation mod_php5 mod_reqtimeout mod_rewrite mod_setenvif mod_ssl mod_status Wordpress 3.4.2 (Upgrading to 3.5 soon :) 2. The problem When I restart the server (sudo shutdown -r now), going to any website page results in the following error from the web browser (in this case, Google Chrome, but other browsers also show the same error). This error can also occur an hour or so after all is working ok, seemingly randomly, which is my biggest concern as it means my server is not reliable: No data received Unable to load the web page because the server sent no data. Here are some suggestions: Reload this web page later. Error 324 (net::ERR_EMPTY_RESPONSE): The server closed the connection without sending any data. 3. Diagnostic information The apache error log contains the folowing entries: [Fri Dec 14 22:23:27 2012] [notice] child pid 1955 exit signal Floating point exception (8) [Fri Dec 14 22:23:27 2012] [notice] child pid 1956 exit signal Floating point exception (8) [Fri Dec 14 22:23:29 2012] [notice] child pid 1957 exit signal Floating point exception (8) [Fri Dec 14 22:23:30 2012] [notice] child pid 1958 exit signal Floating point exception (8) [Fri Dec 14 22:23:32 2012] [notice] child pid 1959 exit signal Floating point exception (8) [Fri Dec 14 22:23:32 2012] [notice] child pid 1960 exit signal Floating point exception (8) [Fri Dec 14 22:23:34 2012] [notice] child pid 1961 exit signal Floating point exception (8) [Fri Dec 14 22:23:34 2012] [notice] child pid 1962 exit signal Floating point exception (8) 4. What I've tried a) I can 'fix' the website temporarily by resetting the server twice (resetting it once does not work) using the following commands. NB: the 'reload' option does not work, I have to use restart twice. However, the error can reoccur sometime later. sudo /etc/init.d/apache2 restart sudo /etc/init.d/apache2 restart b) I have tried disabling suhosin by uninstalling php5-suhosin, but a php info page still shows "This server is protected with the Suhosin Patch 0.9.9.1". I have tried putting Suhosin into simulation mode by creating a file /etc/php5/apache2/conf.d/suhosin.ini containing: [suhosin] suhosin.simulation = On The php info page shows the suhosin.ini file in the list of "Additional .ini files parsed" but the php info page still shows "This server is protected with the Suhosin Patch 0.9.9.1" c) Increasing the PHP memory limit In /etc/php5/apache2/ : ; Maximum amount of memory a script may consume (128MB) ; http://php.net/memory-limit memory_limit = 512M d) Disabling all Wordpress plugins, and going back to the default theme. 5. Specific help needed I would very much like help in debugging what is going on here. I am not sure how to determine what processes are in the Apache error log which are exiting "[notice] child pid 1955 exit signal Floating point exception (8)", or what is causing them to exit. And whether suhosin is part of the problem (and how to disable it if it is). Thank you in advance for any advice or tips you can offer in helping me debug this.

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  • How John Got 15x Improvement Without Really Trying

    - by rchrd
    The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here.  How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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  • 2D grid with multiple types of objects

    - by Alexandre P. Levasseur
    This is my first post here in programmers.stackexchange (I'm a regular on SO). I hope this isn't too general. I'm trying a simple project to learn Java from something I've seen done in the past. Basically, it's an AI simulation where there are herbivorous and carnivorous creatures and both must try to survive. The part I am trying to come up with is that of the board itself. Let's assume very simple rules. The board must be of size X by Y and only one element can be in one place at one time. For example, a critter cannot be in the same tile as a food block. There can be obstacles (rocks, trees..), there can be food, there can be critters of any type. Assuming these rules, what would be one good way to represent this situation ? This is what I came up with and want suggestions if possible: Use multiple levels of inheritance to represent all the different possible objects (AbstractObject - (NonMovingObject - (Food, Obstacle) , MovingObject - Critter - (Carnivorous, Herbivorous))) and use polymorphism in a 2D array to store the instances and still have access to lower level methods. Many thanks. Edit: Here is the graphic representation of the structure I have in mind.

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  • Doubt about texture waves in CG Ocean Shader

    - by Alexandre
    I'm new on graphical programming, and I'm having some trouble understanding the Ocean Shader described on "Effective Water Simulation from Physical Models" from GPU Gems. The source code associated to this article is here. My problem has been to understand the concept of texture waves. First of all, what is achieved by texture waves? I'm having a hard time trying to figure out it's usefulness. In the section 1.2.4 of the article, it does say that the waves summed into the texture have the same parametrization as the waves used for vertex positioning. Does it mean that I can't use the texture provided by the source code if I change the parameters of the waves, or add more waves to sum? And in the section 1.4.1, is said that we can assume that there is no rotation between texture space and world space if the texture coordinates for our normal map are implicit. What does mean that the "normal map are implicit'? And why do I need a rotation between texture and world spaces if the normal map are not implicit? I would be very grateful for any help on this.

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  • Artemis Is The Absolute Geekiest LAN Game You’ll Ever Play [Video]

    - by Jason Fitzpatrick
    Prepare to have your sense of what really geeky computer gaming look like with this Star Trek-like mockup that involves a projector, multiple monitors, and a crew of six. If you have five friends willing to pool some resources–because let us tell you, it’s not going to be cheap to build this gaming setup from scratch–you’re on your way to building a functional starship bridge in your rec room. You’ll need six computers and monitors, a projector to create the front-of-the-bridge-room effect, and a copy of the game–the full retail game is $40 but there is a free demo so you can take the starship simulation for a test spin. The base game is focused on simple simulations like defending your space station and fighting off waves of invaders, however, a recent update of the game supports user-created mission packs. The missions packs allow fans of the game to create intricate missions with objectives to expand the game much like fan-created RPG modules add game play value to table top role-playing games. Hit up the link below to read more about the game or just sit back and enjoy the entertaining video above of sci-fi bloggers manning a starship. Artemis HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? Java is Insecure and Awful, It’s Time to Disable It, and Here’s How What Are the Windows A: and B: Drives Used For?

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  • F# performance vs Erlang performance, is there proof the Erlang's VM is faster?

    - by afuzzyllama
    I've been putting time into learning functional programming and I've come to the part where I want to start writing a project instead of just dabbling in tutorials/examples. While doing my research, I've found that Erlang seems to be a pretty powerful when it comes to writing concurrent software (which is my goal), but resources and tools for development aren't as mature as Microsoft development products. F# can run on linux (Mono) so that requirement is met, but while looking around on the internet I cannot find any comparisons of F# vs Erlang. Right now, I am leaning towards Erlang just because it seems to have the most press, but I am curious if there is really any performance difference between the two languages. Since I am use to developing in .NET, I can probably get up to speed with F# a lot faster than Erlang, but I cannot find any resource to convince me that F# is just as scalable as Erlang. I am most interested in simulation, which is going to be firing a lot of quickly processed messages to persistant nodes. If I have not done a good job with what I am trying to ask, please ask for more verification.

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  • Ogre 3d and bullet physics interaction

    - by Tim
    I have been playing around with Ogre3d and trying to integrate bullet physics. I have previously somewhat successfully got this functionality working with irrlicht and bullet and I am trying to base this on what I had done there, but modifying it to fit with Ogre. It is working but not correctly and I would like some help to understand what it is I am doing wrong. I have a state system and when I enter the "gamestate" I call some functions such as setting up a basic scene, creating the physics simulation. I am doing that as follows. void GameState::enter() { ... // Setup Physics btBroadphaseInterface *BroadPhase = new btAxisSweep3(btVector3(-1000,-1000,-1000), btVector3(1000,1000,1000)); btDefaultCollisionConfiguration *CollisionConfiguration = new btDefaultCollisionConfiguration(); btCollisionDispatcher *Dispatcher = new btCollisionDispatcher(CollisionConfiguration); btSequentialImpulseConstraintSolver *Solver = new btSequentialImpulseConstraintSolver(); World = new btDiscreteDynamicsWorld(Dispatcher, BroadPhase, Solver, CollisionConfiguration); ... createScene(); } In the createScene method I add a light and try to setup a "ground" plane to act as the ground for things to collide with.. as follows. I expect there is issues with this as I get objects colliding with the ground but half way through it and they glitch around like crazy on collision. void GameState::createScene() { m_pSceneMgr->createLight("Light")->setPosition(75,75,75); // Physics // As a test we want a floor plane for things to collide with Ogre::Entity *ent; Ogre::Plane p; p.normal = Ogre::Vector3(0,1,0); p.d = 0; Ogre::MeshManager::getSingleton().createPlane( "FloorPlane", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, p, 200000, 200000, 20, 20, true, 1, 9000,9000,Ogre::Vector3::UNIT_Z); ent = m_pSceneMgr->createEntity("floor", "FloorPlane"); ent->setMaterialName("Test/Floor"); Ogre::SceneNode *node = m_pSceneMgr->getRootSceneNode()->createChildSceneNode(); node->attachObject(ent); btTransform Transform; Transform.setIdentity(); Transform.setOrigin(btVector3(0,1,0)); // Give it to the motion state btDefaultMotionState *MotionState = new btDefaultMotionState(Transform); btCollisionShape *Shape = new btStaticPlaneShape(btVector3(0,1,0),0); // Add Mass btVector3 LocalInertia; Shape->calculateLocalInertia(0, LocalInertia); // CReate the rigid body object btRigidBody *RigidBody = new btRigidBody(0, MotionState, Shape, LocalInertia); // Store a pointer to the Ogre Node so we can update it later RigidBody->setUserPointer((void *) (node)); // Add it to the physics world World->addRigidBody(RigidBody); Objects.push_back(RigidBody); m_pNumEntities++; // End Physics } I then have a method to create a cube and give it rigid body physics properties. I know there will be errors here as I get the items colliding with the ground but not with each other properly. So I would appreciate some input on what I am doing wrong. void GameState::CreateBox(const btVector3 &TPosition, const btVector3 &TScale, btScalar TMass) { Ogre::Vector3 size = Ogre::Vector3::ZERO; Ogre::Vector3 pos = Ogre::Vector3::ZERO; Ogre::Vector3 scale = Ogre::Vector3::ZERO; pos.x = TPosition.getX(); pos.y = TPosition.getY(); pos.z = TPosition.getZ(); scale.x = TScale.getX(); scale.y = TScale.getY(); scale.z = TScale.getZ(); Ogre::Entity *entity = m_pSceneMgr->createEntity( "Box" + Ogre::StringConverter::toString(m_pNumEntities), "cube.mesh"); entity->setCastShadows(true); Ogre::AxisAlignedBox boundingB = entity->getBoundingBox(); size = boundingB.getSize(); //size /= 2.0f; // Only the half needed? //size *= 0.96f; // Bullet margin is a bit bigger so we need a smaller size entity->setMaterialName("Test/Cube"); Ogre::SceneNode *node = m_pSceneMgr->getRootSceneNode()->createChildSceneNode(); node->attachObject(entity); node->setPosition(pos); //node->scale(scale); // Physics btTransform Transform; Transform.setIdentity(); Transform.setOrigin(TPosition); // Give it to the motion state btDefaultMotionState *MotionState = new btDefaultMotionState(Transform); btVector3 HalfExtents(TScale.getX()*0.5f,TScale.getY()*0.5f,TScale.getZ()*0.5f); btCollisionShape *Shape = new btBoxShape(HalfExtents); // Add Mass btVector3 LocalInertia; Shape->calculateLocalInertia(TMass, LocalInertia); // CReate the rigid body object btRigidBody *RigidBody = new btRigidBody(TMass, MotionState, Shape, LocalInertia); // Store a pointer to the Ogre Node so we can update it later RigidBody->setUserPointer((void *) (node)); // Add it to the physics world World->addRigidBody(RigidBody); Objects.push_back(RigidBody); m_pNumEntities++; } Then in the GameState::update() method which which runs every frame to handle input and render etc I call an UpdatePhysics method to update the physics simulation. void GameState::UpdatePhysics(unsigned int TDeltaTime) { World->stepSimulation(TDeltaTime * 0.001f, 60); btRigidBody *TObject; for(std::vector<btRigidBody *>::iterator it = Objects.begin(); it != Objects.end(); ++it) { // Update renderer Ogre::SceneNode *node = static_cast<Ogre::SceneNode *>((*it)->getUserPointer()); TObject = *it; // Set position btVector3 Point = TObject->getCenterOfMassPosition(); node->setPosition(Ogre::Vector3((float)Point[0], (float)Point[1], (float)Point[2])); // set rotation btVector3 EulerRotation; QuaternionToEuler(TObject->getOrientation(), EulerRotation); node->setOrientation(1,(Ogre::Real)EulerRotation[0], (Ogre::Real)EulerRotation[1], (Ogre::Real)EulerRotation[2]); //node->rotate(Ogre::Vector3(EulerRotation[0], EulerRotation[1], EulerRotation[2])); } } void GameState::QuaternionToEuler(const btQuaternion &TQuat, btVector3 &TEuler) { btScalar W = TQuat.getW(); btScalar X = TQuat.getX(); btScalar Y = TQuat.getY(); btScalar Z = TQuat.getZ(); float WSquared = W * W; float XSquared = X * X; float YSquared = Y * Y; float ZSquared = Z * Z; TEuler.setX(atan2f(2.0f * (Y * Z + X * W), -XSquared - YSquared + ZSquared + WSquared)); TEuler.setY(asinf(-2.0f * (X * Z - Y * W))); TEuler.setZ(atan2f(2.0f * (X * Y + Z * W), XSquared - YSquared - ZSquared + WSquared)); TEuler *= RADTODEG; } I seem to have issues with the cubes not colliding with each other and colliding strangely with the ground. I have tried to capture the effect with the attached image. I would appreciate any help in understanding what I have done wrong. Thanks. EDIT : Solution The following code shows the changes I made to get accurate physics. void GameState::createScene() { m_pSceneMgr->createLight("Light")->setPosition(75,75,75); // Physics // As a test we want a floor plane for things to collide with Ogre::Entity *ent; Ogre::Plane p; p.normal = Ogre::Vector3(0,1,0); p.d = 0; Ogre::MeshManager::getSingleton().createPlane( "FloorPlane", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, p, 200000, 200000, 20, 20, true, 1, 9000,9000,Ogre::Vector3::UNIT_Z); ent = m_pSceneMgr->createEntity("floor", "FloorPlane"); ent->setMaterialName("Test/Floor"); Ogre::SceneNode *node = m_pSceneMgr->getRootSceneNode()->createChildSceneNode(); node->attachObject(ent); btTransform Transform; Transform.setIdentity(); // Fixed the transform vector here for y back to 0 to stop the objects sinking into the ground. Transform.setOrigin(btVector3(0,0,0)); // Give it to the motion state btDefaultMotionState *MotionState = new btDefaultMotionState(Transform); btCollisionShape *Shape = new btStaticPlaneShape(btVector3(0,1,0),0); // Add Mass btVector3 LocalInertia; Shape->calculateLocalInertia(0, LocalInertia); // CReate the rigid body object btRigidBody *RigidBody = new btRigidBody(0, MotionState, Shape, LocalInertia); // Store a pointer to the Ogre Node so we can update it later RigidBody->setUserPointer((void *) (node)); // Add it to the physics world World->addRigidBody(RigidBody); Objects.push_back(RigidBody); m_pNumEntities++; // End Physics } void GameState::CreateBox(const btVector3 &TPosition, const btVector3 &TScale, btScalar TMass) { Ogre::Vector3 size = Ogre::Vector3::ZERO; Ogre::Vector3 pos = Ogre::Vector3::ZERO; Ogre::Vector3 scale = Ogre::Vector3::ZERO; pos.x = TPosition.getX(); pos.y = TPosition.getY(); pos.z = TPosition.getZ(); scale.x = TScale.getX(); scale.y = TScale.getY(); scale.z = TScale.getZ(); Ogre::Entity *entity = m_pSceneMgr->createEntity( "Box" + Ogre::StringConverter::toString(m_pNumEntities), "cube.mesh"); entity->setCastShadows(true); Ogre::AxisAlignedBox boundingB = entity->getBoundingBox(); // The ogre bounding box is slightly bigger so I am reducing it for // use with the rigid body. size = boundingB.getSize()*0.95f; entity->setMaterialName("Test/Cube"); Ogre::SceneNode *node = m_pSceneMgr->getRootSceneNode()->createChildSceneNode(); node->attachObject(entity); node->setPosition(pos); node->showBoundingBox(true); //node->scale(scale); // Physics btTransform Transform; Transform.setIdentity(); Transform.setOrigin(TPosition); // Give it to the motion state btDefaultMotionState *MotionState = new btDefaultMotionState(Transform); // I got the size of the bounding box above but wasn't using it to set // the size for the rigid body. This now does. btVector3 HalfExtents(size.x*0.5f,size.y*0.5f,size.z*0.5f); btCollisionShape *Shape = new btBoxShape(HalfExtents); // Add Mass btVector3 LocalInertia; Shape->calculateLocalInertia(TMass, LocalInertia); // CReate the rigid body object btRigidBody *RigidBody = new btRigidBody(TMass, MotionState, Shape, LocalInertia); // Store a pointer to the Ogre Node so we can update it later RigidBody->setUserPointer((void *) (node)); // Add it to the physics world World->addRigidBody(RigidBody); Objects.push_back(RigidBody); m_pNumEntities++; } void GameState::UpdatePhysics(unsigned int TDeltaTime) { World->stepSimulation(TDeltaTime * 0.001f, 60); btRigidBody *TObject; for(std::vector<btRigidBody *>::iterator it = Objects.begin(); it != Objects.end(); ++it) { // Update renderer Ogre::SceneNode *node = static_cast<Ogre::SceneNode *>((*it)->getUserPointer()); TObject = *it; // Set position btVector3 Point = TObject->getCenterOfMassPosition(); node->setPosition(Ogre::Vector3((float)Point[0], (float)Point[1], (float)Point[2])); // Convert the bullet Quaternion to an Ogre quaternion btQuaternion btq = TObject->getOrientation(); Ogre::Quaternion quart = Ogre::Quaternion(btq.w(),btq.x(),btq.y(),btq.z()); // use the quaternion with setOrientation node->setOrientation(quart); } } The QuaternionToEuler function isn't needed so that was removed from code and header files. The objects now collide with the ground and each other appropriately.

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  • The Citroen GT – An Awesome Video Game Car Brought to Life [Video]

    - by Asian Angel
    If you are familiar with the Gran Turismo 5 video game releases, then you will definitely recognize the Citroen GT. French automaker Citroen and Japanese racing simulation developer Polyphony Digital decided to take things one step further and collaborated to bring this awesome car to life. Then they turned it loose on the streets of London! Citroen GT on the Streets of London (HD) [via BoingBoing] You can learn more about the Citroen GT, car show appearances, and more at Wikipedia: GT by Citroen Latest Features How-To Geek ETC How to Enable User-Specific Wireless Networks in Windows 7 How to Use Google Chrome as Your Default PDF Reader (the Easy Way) How To Remove People and Objects From Photographs In Photoshop Ask How-To Geek: How Can I Monitor My Bandwidth Usage? Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware The Citroen GT – An Awesome Video Game Car Brought to Life [Video] Final Man vs. Machine Round of Jeopardy Unfolds; Watson Dominates Give Chromium-Based Browser Desktop Notifications a Native System Look in Ubuntu Chrome Time Track Is a Simple Task Time Tracker Google Sky Map Turns Your Android Phone into a Digital Telescope Walking Through a Seaside Village Wallpaper

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  • Can't shrink Windows Boot NTFS disk: ERROR(5): Could not map attribute 0x80 in inode, Input/output error

    - by arcyqwerty
    Ubuntu 12.04 LTS, all updates current as of 7/3/2012 gksudo gparted Shrink /dev/sda2 from 367GB to 307GB GParted 0.11.0 --enable-libparted-dmraid Libparted 2.3 Shrink /dev/sda2 from 367.00 GiB to 307.00 GiB 00:32:57 ( ERROR ) calibrate /dev/sda2 00:00:00 ( SUCCESS ) path: /dev/sda2 start: 20,484,096 end: 790,142,975 size: 769,658,880 (367.00 GiB) check file system on /dev/sda2 for errors and (if possible) fix them 00:00:53 ( SUCCESS ) ntfsresize -P -i -f -v /dev/sda2 ntfsresize v2012.1.15AR.1 (libntfs-3g) Device name : /dev/sda2 NTFS volume version: 3.1 Cluster size : 4096 bytes Current volume size: 394065338880 bytes (394066 MB) Current device size: 394065346560 bytes (394066 MB) Checking for bad sectors ... Checking filesystem consistency ... Accounting clusters ... Space in use : 327950 MB (83.2%) Collecting resizing constraints ... Estimating smallest shrunken size supported ... File feature Last used at By inode $MFT : 389998 MB 0 Multi-Record : 394061 MB 386464 $MFTMirr : 314823 MB 1 Compressed : 394064 MB 1019521 Sparse : 330887 MB 752454 Ordinary : 393297 MB 706060 You might resize at 327949758464 bytes or 327950 MB (freeing 66116 MB). Please make a test run using both the -n and -s options before real resizing! shrink file system 00:32:04 ( ERROR ) run simulation 00:32:04 ( ERROR ) ntfsresize -P --force --force /dev/sda2 -s 329640837119 --no-action ntfsresize v2012.1.15AR.1 (libntfs-3g) Device name : /dev/sda2 NTFS volume version: 3.1 Cluster size : 4096 bytes Current volume size: 394065338880 bytes (394066 MB) Current device size: 394065346560 bytes (394066 MB) New volume size : 329640829440 bytes (329641 MB) Checking filesystem consistency ... Accounting clusters ... Space in use : 327950 MB (83.2%) Collecting resizing constraints ... Needed relocations : 13300525 (54479 MB) Schedule chkdsk for NTFS consistency check at Windows boot time ... Resetting $LogFile ... (this might take a while) Relocating needed data ... Updating $BadClust file ... Updating $Bitmap file ... ERROR(5): Could not map attribute 0x80 in inode 1667593: Input/output error ======================================== Windows has run chkdsk successfully (on boot) several times now

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  • Mission critical embedded language

    - by Moe
    Maybe the question sounds a bit strange, so i'll explain a the background a little bit. Currently i'm working on a project at y university, which will be a complete on-board software for an satellite. The system is programmed in c++ on top of a real-time operating system. However, some subsystems like the attitude control system and the fault detection and a space simulation are currently only implemented in Matlab/Simulink, to prototype the algorithms efficiently. After their verification, they will be translated into c++. The complete on-board software grew very complex, and only a handful people know the whole system. Furthermore, many of the students haven't program in c++ yet and the manual memory management of c++ makes it even more difficult to write mission critical software. Of course the main system has to be implemented in c++, but i asked myself if it's maybe possible to use an embedded language to implement the subsystem which are currently written in Matlab. This embedded language should feature: static/strong typing and compiler checks to minimize runtime errors small memory usage, and relative fast runtime attitude control algorithms are mainly numerical computations, so a good numeric support would be nice maybe some sort of functional programming feature, matlab/simulink encourage you to use it too I googled a bit, but only found Lua. It looks nice, but i would not use it in mission critical software. Have you ever encountered a situation like this, or do you know any language, which could satisfies the conditions? EDIT: To clarify some things: embedded means it should be able to embed the language into the existing c++ environment. So no compiled languages like Ada or Haskell ;)

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  • Converting 2D Physics to 3D.

    - by static void main
    I'm new to game physics and I am trying to adapt a simple 2D ball simulation for a 3D simulation with the Java3D library. I have this problem: Two things: 1) I noted down the values generated by the engine: X/Y are too high and minX/minY/maxY/maxX values are causing trouble. Sometimes the balls are drawing but not moving Sometimes they are going out of the panel Sometimes they're moving on little area Sometimes they just stick at one place... 2) I'm unable to select/define/set the default correct/suitable values considering the 3D graphics scaling/resolution while they are set with respect to 2D screen coordinates, that is my only problem. Please help. This is the code: public class Ball extends GameObject { private float x, y; // Ball's center (x, y) private float speedX, speedY; // Ball's speed per step in x and y private float radius; // Ball's radius // Collision detected by collision detection and response algorithm? boolean collisionDetected = false; // If collision detected, the next state of the ball. // Otherwise, meaningless. private float nextX, nextY; private float nextSpeedX, nextSpeedY; private static final float BOX_WIDTH = 640; private static final float BOX_HEIGHT = 480; /** * Constructor The velocity is specified in polar coordinates of speed and * moveAngle (for user friendliness), in Graphics coordinates with an * inverted y-axis. */ public Ball(String name1,float x, float y, float radius, float speed, float angleInDegree, Color color) { this.x = x; this.y = y; // Convert velocity from polar to rectangular x and y. this.speedX = speed * (float) Math.cos(Math.toRadians(angleInDegree)); this.speedY = speed * (float) Math.sin(Math.toRadians(angleInDegree)); this.radius = radius; } public void move() { if (collisionDetected) { // Collision detected, use the values computed. x = nextX; y = nextY; speedX = nextSpeedX; speedY = nextSpeedY; } else { // No collision, move one step and no change in speed. x += speedX; y += speedY; } collisionDetected = false; // Clear the flag for the next step } public void collideWith() { // Get the ball's bounds, offset by the radius of the ball float minX = 0.0f + radius; float minY = 0.0f + radius; float maxX = 0.0f + BOX_WIDTH - 1.0f - radius; float maxY = 0.0f + BOX_HEIGHT - 1.0f - radius; double gravAmount = 0.9811111f; double gravDir = (90 / 57.2960285258); // Try moving one full step nextX = x + speedX; nextY = y + speedY; System.out.println("In serializedBall in collision."); // If collision detected. Reflect on the x or/and y axis // and place the ball at the point of impact. if (speedX != 0) { if (nextX > maxX) { // Check maximum-X bound collisionDetected = true; nextSpeedX = -speedX; // Reflect nextSpeedY = speedY; // Same nextX = maxX; nextY = (maxX - x) * speedY / speedX + y; // speedX non-zero } else if (nextX < minX) { // Check minimum-X bound collisionDetected = true; nextSpeedX = -speedX; // Reflect nextSpeedY = speedY; // Same nextX = minX; nextY = (minX - x) * speedY / speedX + y; // speedX non-zero } } // In case the ball runs over both the borders. if (speedY != 0) { if (nextY > maxY) { // Check maximum-Y bound collisionDetected = true; nextSpeedX = speedX; // Same nextSpeedY = -speedY; // Reflect nextY = maxY; nextX = (maxY - y) * speedX / speedY + x; // speedY non-zero } else if (nextY < minY) { // Check minimum-Y bound collisionDetected = true; nextSpeedX = speedX; // Same nextSpeedY = -speedY; // Reflect nextY = minY; nextX = (minY - y) * speedX / speedY + x; // speedY non-zero } } speedX += Math.cos(gravDir) * gravAmount; speedY += Math.sin(gravDir) * gravAmount; } public float getSpeed() { return (float) Math.sqrt(speedX * speedX + speedY * speedY); } public float getMoveAngle() { return (float) Math.toDegrees(Math.atan2(speedY, speedX)); } public float getRadius() { return radius; } public float getX() { return x; } public float getY() { return y; } public void setX(float f) { x = f; } public void setY(float f) { y = f; } } Here's how I'm drawing the balls: public class 3DMovingBodies extends Applet implements Runnable { private static final int BOX_WIDTH = 800; private static final int BOX_HEIGHT = 600; private int currentNumBalls = 1; // number currently active private volatile boolean playing; private long mFrameDelay; private JFrame frame; private int currentFrameRate; private Ball[] ball = new Ball[currentNumBalls]; private Random rand; private Sphere[] sphere = new Sphere[currentNumBalls]; private Transform3D[] trans = new Transform3D[currentNumBalls]; private TransformGroup[] objTrans = new TransformGroup[currentNumBalls]; public 3DMovingBodies() { rand = new Random(); float angleInDegree = rand.nextInt(360); setLayout(new BorderLayout()); GraphicsConfiguration config = SimpleUniverse .getPreferredConfiguration(); Canvas3D c = new Canvas3D(config); add("Center", c); ball[0] = new Ball(0.5f, 0.0f, 0.5f, 0.4f, angleInDegree, Color.yellow); // ball[1] = new Ball(1.0f, 0.0f, 0.25f, 0.8f, angleInDegree, // Color.yellow); // ball[2] = new Ball(0.0f, 1.0f, 0.15f, 0.11f, angleInDegree, // Color.yellow); trans[0] = new Transform3D(); // trans[1] = new Transform3D(); // trans[2] = new Transform3D(); sphere[0] = new Sphere(0.5f); // sphere[1] = new Sphere(0.25f); // sphere[2] = new Sphere(0.15f); // Create a simple scene and attach it to the virtual universe BranchGroup scene = createSceneGraph(); SimpleUniverse u = new SimpleUniverse(c); u.getViewingPlatform().setNominalViewingTransform(); u.addBranchGraph(scene); startSimulation(); } public BranchGroup createSceneGraph() { // Create the root of the branch graph BranchGroup objRoot = new BranchGroup(); for (int i = 0; i < currentNumBalls; i++) { // Create a simple shape leaf node, add it to the scene graph. objTrans[i] = new TransformGroup(); objTrans[i].setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); Transform3D pos1 = new Transform3D(); pos1.setTranslation(randomPos()); objTrans[i].setTransform(pos1); objTrans[i].addChild(sphere[i]); objRoot.addChild(objTrans[i]); } BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0); Color3f light1Color = new Color3f(1.0f, 0.0f, 0.2f); Vector3f light1Direction = new Vector3f(4.0f, -7.0f, -12.0f); DirectionalLight light1 = new DirectionalLight(light1Color, light1Direction); light1.setInfluencingBounds(bounds); objRoot.addChild(light1); // Set up the ambient light Color3f ambientColor = new Color3f(1.0f, 1.0f, 1.0f); AmbientLight ambientLightNode = new AmbientLight(ambientColor); ambientLightNode.setInfluencingBounds(bounds); objRoot.addChild(ambientLightNode); return objRoot; } public void startSimulation() { playing = true; Thread t = new Thread(this); t.start(); } public void stop() { playing = false; } public void run() { long previousTime = System.currentTimeMillis(); long currentTime = previousTime; long elapsedTime; long totalElapsedTime = 0; int frameCount = 0; while (true) { currentTime = System.currentTimeMillis(); elapsedTime = (currentTime - previousTime); // elapsed time in // seconds totalElapsedTime += elapsedTime; if (totalElapsedTime > 1000) { currentFrameRate = frameCount; frameCount = 0; totalElapsedTime = 0; } for (int i = 0; i < currentNumBalls; i++) { ball[i].move(); ball[i].collideWith(); drawworld(); } try { Thread.sleep(88); } catch (Exception e) { e.printStackTrace(); } previousTime = currentTime; frameCount++; } } public void drawworld() { for (int i = 0; i < currentNumBalls; i++) { printTG(objTrans[i], "SteerTG"); trans[i].setTranslation(new Vector3f(ball[i].getX(), ball[i].getY(), 0.0f)); objTrans[i].setTransform(trans[i]); } } private Vector3f randomPos() /* * Return a random position vector. The numbers are hardwired to be within * the confines of the box. */ { Vector3f pos = new Vector3f(); pos.x = rand.nextFloat() * 5.0f - 2.5f; // -2.5 to 2.5 pos.y = rand.nextFloat() * 2.0f + 0.5f; // 0.5 to 2.5 pos.z = rand.nextFloat() * 5.0f - 2.5f; // -2.5 to 2.5 return pos; } // end of randomPos() public static void main(String[] args) { System.out.println("Program Started"); 3DMovingBodiesbb = new 3DMovingBodies(); bb.addKeyListener(bb); MainFrame mf = new MainFrame(bb, 600, 400); } }

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  • How can I route packets from one application to a virtual machine in windows 7?

    - by user836045
    I am trying to test an application running in windows 7, and I would like to send the packets it generates to a server VM (I am using virtualbox) on the local machine which will act as a simulation for when packets will be really sent over the internet to a distant server. I need to check for correctness of the packets in certain situations. Is there a way on windows to take packets produced by an application and instead of passing it to my router, pass it along to another process, i.e. my virtual machine. I'd prefer not to change any of the code on my application and would rather find an outside solution. Is there such a solution for windows 7?

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  • If not gamedev, what do I do !

    - by brainydexter
    Hi, I am a game dev who was working in the game-industry and then..got laid off. Ever since then, life couldn't get less stressful! During this time, I have met so many other devs who have also been laid off irrespective of the number of years they have been in the game. Now, the problem really gets worse, since I am not a US citizen (yes, I am in US) , and am on an international visa here, I might have to soon pack my bags and go back to my native country. Going back is not bad at all, apart from the fact, that gamedev is still in a very nascent stage there. There just aren't many opportunities. So, employment is the key to maintain a valid visa status. After giving it a lot of thought, I am thinking of staying away from gamedev jobs for the time being, given its job unstablity. This brings me to my current problem. I can't think of a domain/place where I can use my game development skills. I know graphics/simulation/visualization is huge, but I can't think straight and am left clueless where to go from here. What are some of the domains/companies where I can use my skills ? I'd appreciate any insight on this (and I apologize if this is not the place to post this kind of a question).

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  • Close all Mac Terminal windows, but the one running a script

    - by Greg Brown
    I am trying to create a shell script that runs a python simulation programing in 4 terminal windows. I have the script that launches the program four times in four separate terminal windows(total of 5 windows, 4 for the python programs, and one to control the other terminal windows). I want to now create a script that I can run in the control terminal window that closes and kills the programs of the other four terminal windows, but still have the control one open. What I have so far is something like this #!/bin/sh osascript -e 'tell app "Terminal" do script "killall python" end tell' osascript -e 'tell app "Terminal" to quit' osascript -e 'tell app "Terminal" to open' The problem is that the last line doesn't work because it closes all the windows including the one the script is executing in. I am not really familiar with shell or apple script so any help would be welcomed. I posted on Stack, but I think this might be a better place for an automation type question. Thanks

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  • Open source vs commercial game engines

    - by Vanangamudi
    How commercial game accomplsih stunnning graphics with smooth game play? I am a huge die hard fan and follower of GNU Stallman and his philosophies and other Libre people Cmon how wud I miss Linus. but I got to admit commercial games does excellent jobs. One such good example is Assasin's Creed from Ubisoft. It has good quality graphcis and plays smoothly in my Dual core CPU with Nvidia Geforce 8400ES. Rockstar GTA4 has awesome graphcis but it's slower than AC considering the graphics quality tradeoff. Age of Empires from Ensemble studios, does include Massive crowd AI simulation, yet it plays so smoothly with eyecandy graphics and very large weapon sets and different techtree elements on the other hand. Open source games like Glest, 0A.D(still in alpha :) are not so smooth even though they have very restricted abilities? Coming to question: how do game companies achieve such optmizations, or the open source community is not doing optimizations, or there are any propriarity technological elements that benefits only the companies exists huh?? e.g the OpenSubDiv from Pixar just released open to community?? something like that. and why it is hard to implement optimizations? are there any legal restrictions???

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  • Log php errors in ubuntu

    - by resting
    I followed the setup here: Where is the PHP error log When I look into /var/log/php_errors.log, I could see some PHP errors. PHP Warning: file_get_contents(/var/www/...): failed to open stream: No such file or directory in ... But what I'm trying to see is the error when I removed a semicolon from a statement. That error above has no relation to file from where I removed the semicolon so we can just ignore that. When I access the page with the removed semicolon, I get The website encountered an error while retrieving https://myapp/download/decode/testfile. It may be down for maintenance or configured incorrectly. HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request. But no logs in /var/log/php_errors.log. How do I see the error that usually says which line and which file the process failed? The real reason for trying to see the error is because I have a very huge loop, that throws the HTTP 500 error and I can't see the exact error. I'm just simulation with a removed semicolon to test things out. Other settings: error_reporting = E_ALL & ~E_DEPRECATED display_errors = On On Ubuntu 10.04.4 LTS Update Ok, I managed to get the error message to display. Parse error: syntax error, unexpected T_IF in ... However, it's still not logged. It wasn't displaying previously because Cakephp's debug level was at 0. Setting it to 2 displays the message, but no logs.

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  • A Technical Perspective On Rapid Planning

    - by Robert Story
    Upcoming WebcastTitle: Strategic Network Optimization - One Solution for Many Problems!Date: April 14, 2010 Time: 11:00 am EDT, 9:00 am MDT, 8:00 am PDT, 16:00 GMT Product Family: Value Chain PlanningSummary This one-hour session is recommended for System Administrators, Database Administrators, and Technical Users seeking a general overview of Rapid Planning, installation issues, and debug information. This webcast is intended to provide users with insight into known issues, and an overview of the debugging possibilities for Rapid Planning. Topics will include: Benefits of using simulation planning Installing Oracle Rapid planning, points to be aware of Relevant tables Rapid planning log files Information needed by supportA short, live demonstration (only if applicable) and question and answer period will be included. Click here to register for this session....... ....... ....... ....... ....... ....... .......The above webcast is a service of the E-Business Suite Communities in My Oracle Support.For more information on other webcasts, please reference the Oracle Advisor Webcast Schedule.Click here to visit the E-Business Communities in My Oracle Support Note that all links require access to My Oracle Support.

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  • BPM PS6 video showing process lifecycle in more detail (30min) by Mark Nelson

    - by JuergenKress
    If the five minute video I shared last week has whet your appetite for more, then this might be just what you are looking for! The same international team that has made that video - Andrew Dorman, Tanya Williams, Carlos Casares, Joakim Suarez and James Calise – have also created a thirty minute version that walks through in much more detail and shows you, from the perspective of various business stakeholders involved in process modeling, exactly how BPM PS6 supports the end to end process lifecycle. The video centres around a Retail Leasing use case, and follows how Joakim the Business Analyst, Pablo the Process Owner, and James the Process Analyst take the process from conception to runtime, solely through BPM Composer, without the need for IT or the use of JDeveloper. Joakim, the Business Analyst, models the process, designs the user interaction forms, and creates business rules, Pablo, the Process Owner, reviews the process documentation and tests the process using the new ‘Process Player’, James, the Process Analyst, analyses the process and identifies potential bottle necks using ‘Process Simulation’. Read the full article here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: BPM PS6,BPM,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • Java Spotlight Episode 87: Nandini Ramani on Java FX and Embedded Java

    - by Roger Brinkley
    Interview with Nandini Ramani on JavaFX and Embedded Java. Joining us this week on the Java All Star Developer Panel is Arun Gupta, Java EE Guy. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News JFXtras Project: There’s an app for that! JavaOne 2012 content catalog is online Native packaging for JavaFX in 2.2 EL 3.0 Public Review (JSR 341) el-spec.java.net Events June 18-20, QCon, New York City June 19, CJUG, Chicago June 20, 1871, Chicago June 26-28, Jazoon, Zurich, Switzerland Jun 27, Houston JUG July 5, Java Forum, Stuttgart, Germany Jul 13-14, IndicThreads, Delhi July 30-August 1, JVM Language Summit, Santa Clara Feature InterviewNandini Ramani is Vice President of Development at Oracle in the Fusion Middleware Group. She is responsible for the Java Client Platform and has a long history of creating innovation and futures at Sun Microsystems.Nandini launched the JavaFX Platform and tools and had been actively involved in JavaFX since its inception in May 2007. Prior to joining the client group, Nandini was in the Software CTO Office driving the emerging technologies group for incubation projects. She has a background in both hardware and software, having worked in hardware architecture and simulation team in the Accelerated Graphics group and the graphics and media team in the JavaME group. She was involved in the development of XML standards, as Co-Chair of the W3C Scalable Vector Graphics working group and as a member of the W3C Compound Document Formats working group. She was also a member of several graphics and UI related expert groups in the JCP. Mail Bag What’s Cool "OpenJDK is now the heart of a vital piece of technology that runs large parts of our entire civilization.” Java Magazine PetStore using Java EE 6 - Antonio Goncalves

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  • multi user web game with scheduled processing?

    - by Rooq
    I have an idea for a game which I am in the process of designing, but I am struggling to establish if the way I plan to implement it is possible. The game is a text based sports management simulation. This will require players to take certain actions through a web browser which will interact with a database - adding/updating and selecting. Most of the code required to be executed at this point will be fairly straightforward. The main processing will take place by applications which are scheduled to run on the server at certain times. These apps will process transactions added by the players and also perform some automatic processing based on the game date. My plan was to use an SQL server database (at last count I require about 20 tables) and VB.net for all the coding (coming from a mainframe programming background this language is the simplist for me to get to grips with). I will also need a scheduling tool on the server. Can anyone tell me if what I am planning is feasible before I dive into the actual coding stage of my project?

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  • CodePlex Daily Summary for Monday, January 03, 2011

    CodePlex Daily Summary for Monday, January 03, 2011Popular ReleasesStyleCop for ReSharper: StyleCop for ReSharper 5.1.14977.000: Prerequisites: ============== o Visual Studio 2008 / Visual Studio 2010 o ReSharper 5.1.1753.4 o StyleCop 4.4.1.2 Preview This release adds no new features, has bug fixes around performance and unhandled errors reported on YouTrack.Morphine: Morphine Alpha Build 30: - Optimization - Some fixes with playlists - Added kinetic scrolling to tracklist view - Updated animations - Added controls to tracklist view Media opens by clicking "No media" or song title now.BloodSim: BloodSim - 1.3.1.0: - Restructured simulation log back end to something less stupid to drastically reduce simulation time and memory usage - Removed a debug log entry that was left over from testing of 1.3.0.0 - Fixed a rounding and calculation error with Haste rating - Added option for Rune of SwordshatteringDbDocument: DbDoc Initial Version: DbDoc Initial versionUltimateJB: UltimateJB 2.03 PL3 KAKAROTO: Voici une version attendu avec impatience pour beaucoup : - La version PL3 KAKAROTO intégre ses dernières modification et intégre maintenant le firmware 2.43 !!! Conclusion : - ultimateJB DEFAULT => Pas de spoof mais disponible pour les PS3 suivantes : 3.41_kiosk 3.41 3.40 3.30 3.21 3.15 3.10 3.01 2.76 2.70 2.60 2.53 2.43ASP .NET MVC CMS (Content Management System): Atomic CMS 2.1.2: Atomic CMS 2.1.2 release notes Atomic CMS installation guide Kind Of Magic MSBuild Task: Beta 4: Update to keep up with latest bug fixes. To those who don't like Magic/NoMagic attributes, you may change these names in KindOfMagic.targets file: Change this line: <MagicTask Assembly="@(IntermediateAssembly)" References="@(ReferencePath)"/> to something like this: <MagicTask Assembly="@(IntermediateAssembly)" References="@(ReferencePath)" MagicAttribute="MyMagicAttribute" NoMagicAttribute="MyNoMagicAttribute"/>N2 CMS: 2.1: N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. Major Changes Support for auto-implemented properties ({get;set;}, based on contribution by And Poulsen) All-round improvements and bugfixes File manager improvements (multiple file upload, resize images to fit) New image gallery Infinite scroll paging on news Content templates First time with N2? Try the demo site Download one of the template packs (above) and open the proj...Wii Backup Fusion: Wii Backup Fusion 1.0: - Norwegian translation - French translation - German translation - WBFS dump for analysis - Scalable full HQ cover - Support for log file - Load game images improved - Support for image splitting - Diff for images after transfer - Support for scrubbing modes - Search functionality for log - Recurse depth for Files/Load - Show progress while downloading game cover - Supports more databases for cover download - Game cover loading routines improvedAutoLoL: AutoLoL v1.5.1: Fix: Fixed a bug where pressing Save As would not select the Mastery Directory by default Unexpected errors are now always reported to the user before closing AutoLoL down.* Extracted champion data to Data directory** Added disclaimer to notify users this application has nothing to do with Riot Games Inc. Updated Codeplex image * An error report will be shown to the user which can help the developers to find out what caused the error, this should improve support ** We are working on ...Random password generator written in F#.: VS 2010 solution + exe: Download a VS 2010 solution (unzip before opening) or a ready to go exe.TortoiseHg: TortoiseHg 1.1.8: TortoiseHg 1.1.8 is a minor bug fix release, with minor improvementsBlogEngine.NET: BlogEngine.NET 2.0: Get DotNetBlogEngine for 3 Months Free! Click Here for More Info 3 Months FREE – BlogEngine.NET Hosting – Click Here! If you want to set up and start using BlogEngine.NET right away, you should download the Web project. If you want to extend or modify BlogEngine.NET, you should download the source code. If you are upgrading from a previous version of BlogEngine.NET, please take a look at the Upgrading to BlogEngine.NET 2.0 instructions. To get started, be sure to check out our installatio...EnhSim: EnhSim 2.2.8 ALPHA: 2.2.8 ALPHAThis release supports WoW patch 4.03a at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 Rebuilt Feral Spir...Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.6.6 Released: Hi, Today we are releasing final version of Visifire, v3.6.6 with the following new feature: * TextDecorations property is implemented in Title for Chart. * TitleTextDecorations property is implemented in Axis. * MinPointHeight property is now applicable for Column and Bar Charts. Also this release includes few bug fixes: * ToolTipText property of DataSeries was not getting applied from Style. * Chart threw exception if IndicatorEnabled property was set to true and Too...StyleCop Compliant Visual Studio Code Snippets: Visual Studio Code Snippets - January 2011: StyleCop Compliant Visual Studio Code Snippets Visual Studio 2010 provides C# developers with 38 code snippets, enhancing developer productivty and increasing the consistency of the code. Within this project the original code snippets have been refactored to provide StyleCop compliant versions of the original code snippets while also adding many new code snippets. Within the January 2011 release you'll find 82 code snippets to make you more productive and the code you write more consistent!...WPF Application Framework (WAF): WPF Application Framework (WAF) 2.0.0.2: Version: 2.0.0.2 (Milestone 2): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Remark The sample applications are using Microsoft’s IoC container MEF. However, the WPF Application Framework (WAF) doesn’t force you to use the same IoC container in your application. You can use ...Cosmos (C# Open Source Managed Operating System): 71406: This is the second release supporting the full line of Visual Studio 2010 editions. Changes since release 71246 include: Debug info is now stored in a single .cpdb file (which is a Firebird database) Keyboard input works now (using Console.ReadLine) Console colors work (using Console.ForegroundColor and .BackgroundColor)Paint.NET PSD Plugin: 1.6.0: Handling of layer masks has been greatly improved. Improved reliability. Many PSD files that previously loaded in as garbage will now load in correctly. Parallelized loading. PSD files containing layer masks will load in a bit quicker thanks to the removal of the sequential bottleneck. Hidden layers are no longer made visible on save. Many thanks to the users who helped expose the layer masks problem: Rob Horowitz, M_Lyons10. Please keep sending in those bug reports and PSD repro files!Facebook C# SDK: 4.1.1: From 4.1.1 Release: Authentication bug fix caused by facebook change (error with redirects in Safari) Authenticator fix, always returning true From 4.1.0 Release Lots of bug fixes Removed Dynamic Runtime Language dependencies from non-dynamic platforms. Samples included in release for ASP.NET, MVC, Silverlight, Windows Phone 7, WPF, WinForms, and one Visual Basic Sample Changed internal serialization to use Json.net BREAKING CHANGE: Canvas Session is no longer supported. Use Signed...New ProjectsAndroid Battery Indicator: Small widget that shows the battery life as a percentageBudget: A personal exploration into C#. A quickly thrown together project that allows you to track expenses by week. MS Access back end.Cafeteria Dotnetnuke Module: Simple Dotnetnuke Module about Managing Cafeteria. This module was applied at Ho Chi Minh City International University Portal Website.E Book Database & Organizer: This Is a project to organize ebooks and retrive information about them very fast.Later a free e-library software may be developed based on this project. This project mainly developed with visual C#2008express edition.It also can compiled by mono. It use SQLite as database. GrowlWebBridge: Using c# Growl connector library, accept notification parameters via querystring and fire off to Growl. I'm personally using it to have my Vera 2 (www.micasaverde.com) send growls when things happen.JakoPiste: N/AJAudit: Static analysis for java programs. Helps audit java code. Reports possible code improvements. 100% C#.Morphine: Morphine is a nice WPF media player with Android Honeycomb interface.NUnit test template for VS2010 Express MVC 2: This is an attempt to create a set of template of NUnit (a test framework) for MVC 2 in Visual Studio 2010 Express.Orchard Image Field Module: Orchard Image Field Module adds a new Image editor to content type management. PDB2MOBI batch convert: Converts PDB files to MOBI format in batch. Used primary to convert large PDB libraries for Kindle.Random password generator written in F#.: A password generator that creates random and strong passwords. It's developed in F#. Robots Routing using Swarm Intelligence: A project to simulate and test a multiagent algorithm for finding multiple noisy radiation Sources with spatial and communication constraints with an emulated environment with different parameters and conditions. sanmei: sanmeiServer DateTime: Server DateTime renders the date and time from the server and make it active using javascript. It is in Military Time Format.Windows K: Microsoft Imagine Cup 2011 Project

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  • XNA C# Platformer - physics engine or tile based?

    - by Hugh
    I would like to get some opinions on whether i should develop my game using a physics engine (farseer physics seems to be the best option) or follow the traditional tile-based method. Quick background: - its a college project, my first game, but have 4 years academic programming experience - Just want a basic platformer with a few levels, nothing fancy - want a shooting mechanic, run and gun, just like contra or metal slug for example - possibly some simple puzzles I have made a basic prototype with farseer, the level is hardcoded with collisions and not really tiled, more like big full-screen sized tiles, with collision bodies drawn manually along the ground and walls etc. My main problem is i want a simple retro feel to the jumping and physics but because its a physics simulation engine its going to be realistic, whereas typical in air controllable physics for platformers arent realistic. I have to make a box with wheel body fixture under it to have this effect and its glitchy and doesnt feel right. I chose to use a physics engine because i tried the tile method initially and found it very hard to understand, the engine took care of alot things to save me time, mainly being able to do slopes easily was nice and the freedom to draw collision bounds wherever i liked, rather then restricted to a grid, which gave me more freedom for art design also. In conclusion i don't know which method to pick, i want to use a method which will be the most straight forward way to implement and wont give me a headache later on, preferably a method which has an abundance of tutorials and resources so i dont get "stuck" doing something which has been done a million times before! Let me know i haven't provided enough information for you to help me! Thanks in advance, Hugh.

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