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  • Windows Mobile 7 corporate device...

    - by Toymaker
    Does anyone know of a Windows Mobile 7 device aimed at business use? I’m looking for something with bar code scanning capability. Psion, hand held, and honeywell only offer 6.5 at the moment. Granted, Windows Mobile 7 just barely came out and these sorts of devices usually lag a bit behind consumer toys...but hopefully someone can help.

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  • Could not load drivers - Code 31

    - by alexander7567
    I get this error when installing any network adapter on my computer: The device is not working properly because Windows cannot load the drivers required for this device. (Code 31) I have tried many different adapters and many different drivers. Any ideas? OS: Windows XP Home SP3 Here is the Hardware IDs for the onboard NIC: PCI\VEN_8086&DEV_1050&SUBSYS_2019107B&REV_02 PCI\VEN_8086&DEV_1050&SUBSYS_2019107B PCI\VEN_8086&DEV_1050&CC_020000 PCI\VEN_8086&DEV_1050&CC_0200 Device Manager Screenshot

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  • VBA code to hide or unhide rows based on a cell value

    - by I AM L
    Heres my code, but its not really doing anything, I dont see anything wrong with it: Private Sub PG1(ByVal Target As Range) If .Range("E50").Value = "Passed" Then Rows("51").EntireRow.Hidden = True End If ElseIf Range("E50").Value = "Failed" Then Rows("51").EntireRow.Hidden = True End If End Sub My intention is that when that specific cell in the previous row is set to "Passed" from the dropdown, then the below row would appear, if its a 'Failed" then it'll be hidden instead.

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  • Response code for Chinese spiders? [closed]

    - by pt2ph8
    My server is being "attacked" by Chinese spiders that don't respect the rules in my robots.txt. They are being very aggressive and using a lot of resources, so I'm going to set up some rules in nginx to block them by user agent. Question: which response code should I return, 403, 444 (empty response in nginx) or something else? I'm wondering how the spiders will react to different status codes. What's the best practice?

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  • developing code in multiple locations

    - by jason m
    I have two machines (one is a mac one is a pc), and I develop on both machines but only run "production" on the pc. Now, I sometimes face an issue where both machine PC and machine MAC have different versions of the same code, and I would like them to share a common source. I know this solution must exist but I have no ideat what it is called/how to start. Could someone please point me in the right direction?

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  • Command /Developer/usr/bin/dsymutil failed with exit code 10

    - by Evan Robinson
    I am getting the above error message randomly (so far as I can tell) on iPhone projects. Occasionally it will go away upon either: Clean Restart XCode Reboot Reinstall XCode But sometimes it won't. When it won't the only solution I have found is to take all the source material, import it into a new project, and then redo all the connections in IB. Then I'm good until it strikes again. Anybody have any suggestions? [update 20091030] I have tried building both debug and release versions, both full and lite versions. I've also tried switching the debug symbols from DWARF with external dSYM file to DWARF and to stabs. Clean builds in all formats make no differences. Permission repairs change nothing. Setting up a new user has no effect. Same error on the builds. Thanks for the suggestions! [Update 20091031] Here's an easier and (apparently) reliable workaround. It hinges upon the discovery that the problem is linked to a target not a project In the same project file, create a new target Option-Drag (copy) all the files from the BAD target 'Copy Bundle Resources' folder to the NEW target 'Copy Bundle Resources' folder Repeat (2) with 'Compile Sources' and 'Link Binary With Libraries' Duplicate the Info.plist file for the BAD target and name it correctly for the NEW target. Build the NEW target! [Update 20100222] Apparently an IDE bug, now apparently fixed, although Apple does not allow direct access to the original bug of a duplicate. I can no longer reproduce this behaviour, so hopefully it is dead, dead, dead.

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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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  • SQLExpress service unable to start Error code 17053

    - by Chris Sobolewski
    A user was instructed by their software support to upgrade a program and install SQLExpress as part of the installation process. Since that time, the service has been able to start, citing error 17053, which appears to be an authentication issue. Here is the error log: 2011-01-11 13:17:45.50 Server Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86) Feb 9 2007 22:47:07 Copyright (c) 1988-2005 Microsoft Corporation Express Edition on Windows NT 5.1 (Build 2600: Service Pack 2) 2011-01-11 13:17:45.50 Server (c) 2005 Microsoft Corporation. 2011-01-11 13:17:45.50 Server All rights reserved. 2011-01-11 13:17:45.50 Server Server process ID is 3332. 2011-01-11 13:17:45.50 Server Authentication mode is WINDOWS-ONLY. 2011-01-11 13:17:45.50 Server Logging SQL Server messages in file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG'. 2011-01-11 13:17:45.52 Server This instance of SQL Server last reported using a process ID of 2332 at 11/10/2010 2:15:24 PM (local) 11/10/2010 7:15:24 PM (UTC). This is an informational message only; no user action is required. 2011-01-11 13:17:45.52 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 2011-01-11 13:17:45.52 Server Registry startup parameters: 2011-01-11 13:17:45.52 Server -d c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf 2011-01-11 13:17:45.52 Server -e c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG 2011-01-11 13:17:45.52 Server -l c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\mastlog.ldf 2011-01-11 13:17:45.52 Server Error: 17113, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server Error 3(The system cannot find the path specified.) occurred while opening file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf' to obtain configuration information at startup. An invalid startup option might have caused the error. Verify your startup options, and correct or remove them if necessary. 2011-01-11 13:17:45.52 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 4 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:08:21.34 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 12:47:20.85 spid5s SQL Trace ID 1 was started by login "sa". 2011-01-11 12:47:20.90 spid5s Starting up database 'mssqlsystemresource'. 2011-01-11 12:47:20.93 spid5s The resource database build version is 9.00.3042. This is an informational message only. No user action is required. 2011-01-11 12:47:21.21 spid5s Error: 15466, Severity: 16, State: 1. 2011-01-11 12:47:21.21 spid5s An error occurred during decryption. 2011-01-11 12:47:21.38 spid8s Starting up database 'model'. 2011-01-11 12:47:21.38 Server Error: 17182, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server TDSSNIClient initialization failed with error 0x5, status code 0x90. 2011-01-11 12:47:21.38 Server Error: 17182, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server TDSSNIClient initialization failed with error 0x5, status code 0x1. 2011-01-11 12:47:21.38 Server Error: 17826, Severity: 18, State: 3. 2011-01-11 12:47:21.38 Server Could not start the network library because of an internal error in the network library. To determine the cause, review the errors immediately preceding this one in the error log. 2011-01-11 12:47:21.38 Server Error: 17120, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server SQL Server could not spawn FRunCM thread. Check the SQL Server error log and the Windows event logs for information about possible related problems. One lead I had was to change the SQL logon account from "Network Service" to "Local System". Unfortunately, that is resulting in the error message The Security ID Structure is Invalid [0x80070539] Any help either uninstalling or getting SQLExpress running would be fantastic.

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  • Vim: Context sensitive code completion for PHP

    - by eddy147
    Vim gives me too much options when I use code completion. In a class, and type $class- it gives me about a zillion options, so not only from the class itself but also from php, all globals ever created, in short: a mess. I only want to have the options from the class itself (or the parent subtype class it extends from), so context or scope sensitive code completion, just like Netbeans for example. How can I do that? My current configuration is this: I am using ctags, and created 1 ctags file for our (big) application in the root. This is the .ctags file I used to create the ctags file: -R -h ".php" --exclude=.svn --languages=+PHP,-JavaScript --tag-relative=yes --regex-PHP=/abstract\s+class\s+([^ ]+)/\1/c/ --regex-PHP=/interface\s+([^ ]+)/\1/c/ --regex-PHP=/(public\s+|static\s+|protected\s+|private\s+)\$([^ \t=]+)/\2/p/ --regex-PHP=/const\s+([^ \t=]+)/\1/d/ --regex-PHP=/final\s+(public\s+|static\s+|abstract\s+|protected\s+|private\s+)function\s+\&?\s*([^ (]+)/\2/f/ --PHP-kinds=+cdf --fields=+iaS This is the .vimrc file: " autocomplete funcs and identifiers for languages autocmd FileType php set omnifunc=phpcomplete#CompletePHP autocmd FileType python set omnifunc=pythoncomplete#Complete autocmd FileType javascript set omnifunc=javascriptcomplete#CompleteJS autocmd FileType html set omnifunc=htmlcomplete#CompleteTags autocmd FileType css set omnifunc=csscomplete#CompleteCSS autocmd FileType xml set omnifunc=xmlcomplete#CompleteTags autocmd FileType php set omnifunc=phpcomplete#CompletePHP autocmd FileType c set omnifunc=ccomplete#Complete " exuberant ctags " the magic is the ';' at end. it will make vim tags file search go up from current directory until it finds one. set tags=projectrootdir/tags; map <F8> :!ctags " TagList " :tag getUser => Jump to getUser method " :tn (or tnext) => go to next search result " :tp (or tprev) => to to previous search result " :ts (or tselect) => List the current tags " => Go back to last tag location " +Left click => Go to definition of a method " More info: " http://vimdoc.sourceforge.net/htmldoc/tagsrch.html (official documentation) " http://www.vim.org/tips/tip.php?tip_id=94 (a vim tip) let Tlist_Ctags_Cmd = "~/bin/ctags" let Tlist_WinWidth = 50 map <F4> :TlistToggle<cr> "see http://vim.wikia.com/wiki/Make_Vim_completion_popup_menu_work_just_like_in_an_IDE " will change the 'completeopt' option so that Vim's popup menu doesn't select the first completion item, but rather just inserts the longest common text of all matches :set completeopt=longest,menuone " will change the behavior of the <Enter> key when the popup menu is visible. In that case the Enter key will simply select the highlighted menu item, just as <C-Y> does :inoremap <expr> <CR> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>" " inoremap <expr> <C-n> pumvisible() ? '<C-n>' : \ '<C-n><C-r>=pumvisible() ? "\<lt>Down>" : ""<CR>' inoremap <expr> <M-,> pumvisible() ? '<C-n>' : \ '<C-x><C-o><C-n><C-p><C-r>=pumvisible() ? "\<lt>Down>" : ""<CR>'

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  • IOC Container Handling State Params in Non-Default Constructor

    - by Mystagogue
    For the purpose of this discussion, there are two kinds of parameters an object constructor might take: state dependency or service dependency. Supplying a service dependency with an IOC container is easy: DI takes over. But in contrast, state dependencies are usually only known to the client. That is, the object requestor. It turns out that having a client supply the state params through an IOC Container is quite painful. I will show several different ways to do this, all of which have big problems, and ask the community if there is another option I'm missing. Let's begin: Before I added an IOC container to my project code, I started with a class like this: class Foobar { //parameters are state dependencies, not service dependencies public Foobar(string alpha, int omega){...}; //...other stuff } I decide to add a Logger service depdendency to the Foobar class, which perhaps I'll provide through DI: class Foobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } But then I'm also told I need to make class Foobar itself "swappable." That is, I'm required to service-locate a Foobar instance. I add a new interface into the mix: class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } When I make the service locator call, it will DI the ILogger service dependency for me. Unfortunately the same is not true of the state dependencies Alpha and Omega. Some containers offer a syntax to address this: //Unity 2.0 pseudo-ish code: myContainer.Resolve<IFoobar>( new parameterOverride[] { {"alpha", "one"}, {"omega",2} } ); I like the feature, but I don't like that it is untyped and not evident to the developer what parameters must be passed (via intellisense, etc). So I look at another solution: //This is a "boiler plate" heavy approach! class Foobar : IFoobar { public Foobar (string alpha, int omega){...}; //...stuff } class FoobarFactory : IFoobarFactory { public IFoobar IFoobarFactory.Create(string alpha, int omega){ return new Foobar(alpha, omega); } } //fetch it... myContainer.Resolve<IFoobarFactory>().Create("one", 2); The above solves the type-safety and intellisense problem, but it (1) forced class Foobar to fetch an ILogger through a service locator rather than DI and (2) it requires me to make a bunch of boiler-plate (XXXFactory, IXXXFactory) for all varieties of Foobar implementations I might use. Should I decide to go with a pure service locator approach, it may not be a problem. But I still can't stand all the boiler-plate needed to make this work. So then I try this: //code named "concrete creator" class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; static IFoobar Create(string alpha, int omega){ //unity 2.0 pseudo-ish code. Assume a common //service locator, or singleton holds the container... return Container.Resolve<IFoobar>( new parameterOverride[] {{"alpha", alpha},{"omega", omega} } ); } //Get my instance: Foobar.Create("alpha",2); I actually don't mind that I'm using the concrete "Foobar" class to create an IFoobar. It represents a base concept that I don't expect to change in my code. I also don't mind the lack of type-safety in the static "Create", because it is now encapsulated. My intellisense is working too! Any concrete instance made this way will ignore the supplied state params if they don't apply (a Unity 2.0 behavior). Perhaps a different concrete implementation "FooFoobar" might have a formal arg name mismatch, but I'm still pretty happy with it. But the big problem with this approach is that it only works effectively with Unity 2.0 (a mismatched parameter in Structure Map will throw an exception). So it is good only if I stay with Unity. The problem is, I'm beginning to like Structure Map a lot more. So now I go onto yet another option: class Foobar : IFoobar, IFoobarInit { public Foobar(ILogger log){...}; public IFoobar IFoobarInit.Initialize(string alpha, int omega){ this.alpha = alpha; this.omega = omega; return this; } } //now create it... IFoobar foo = myContainer.resolve<IFoobarInit>().Initialize("one", 2) Now with this I've got a somewhat nice compromise with the other approaches: (1) My arguments are type-safe / intellisense aware (2) I have a choice of fetching the ILogger via DI (shown above) or service locator, (3) there is no need to make one or more seperate concrete FoobarFactory classes (contrast with the verbose "boiler-plate" example code earlier), and (4) it reasonably upholds the principle "make interfaces easy to use correctly, and hard to use incorrectly." At least it arguably is no worse than the alternatives previously discussed. One acceptance barrier yet remains: I also want to apply "design by contract." Every sample I presented was intentionally favoring constructor injection (for state dependencies) because I want to preserve "invariant" support as most commonly practiced. Namely, the invariant is established when the constructor completes. In the sample above, the invarient is not established when object construction completes. As long as I'm doing home-grown "design by contract" I could just tell developers not to test the invariant until the Initialize(...) method is called. But more to the point, when .net 4.0 comes out I want to use its "code contract" support for design by contract. From what I read, it will not be compatible with this last approach. Curses! Of course it also occurs to me that my entire philosophy is off. Perhaps I'd be told that conjuring a Foobar : IFoobar via a service locator implies that it is a service - and services only have other service dependencies, they don't have state dependencies (such as the Alpha and Omega of these examples). I'm open to listening to such philosophical matters as well, but I'd also like to know what semi-authorative reference to read that would steer me down that thought path. So now I turn it to the community. What approach should I consider that I havn't yet? Must I really believe I've exhausted my options?

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  • Python bindings for C++ code using OpenCV giving segmentation fault

    - by lightalchemist
    I'm trying to write a python wrapper for some C++ code that make use of OpenCV but I'm having difficulties returning the result, which is a OpenCV C++ Mat object, to the python interpreter. I've looked at OpenCV's source and found the file cv2.cpp which has conversions functions to perform conversions to and fro between PyObject* and OpenCV's Mat. I made use of those conversions functions but got a segmentation fault when I tried to use them. I basically need some suggestions/sample code/online references on how to interface python and C++ code that make use of OpenCV, specifically with the ability to return OpenCV's C++ Mat to the python interpreter or perhaps suggestions on how/where to start investigating the cause of the segmentation fault. Currently I'm using Boost Python to wrap the code. Thanks in advance to any replies. The relevant code: // This is the function that is giving the segmentation fault. PyObject* ABC::doSomething(PyObject* image) { Mat m; pyopencv_to(image, m); // This line gives segmentation fault. // Some code to create cppObj from CPP library that uses OpenCV cv::Mat processedImage = cppObj->align(m); return pyopencv_from(processedImage); } The conversion functions taken from OpenCV's source follows. The conversion code gives segmentation fault at the commented line with "if (!PyArray_Check(o)) ...". static int pyopencv_to(const PyObject* o, Mat& m, const char* name = "<unknown>", bool allowND=true) { if(!o || o == Py_None) { if( !m.data ) m.allocator = &g_numpyAllocator; return true; } if( !PyArray_Check(o) ) // Segmentation fault inside PyArray_Check(o) { failmsg("%s is not a numpy array", name); return false; } int typenum = PyArray_TYPE(o); int type = typenum == NPY_UBYTE ? CV_8U : typenum == NPY_BYTE ? CV_8S : typenum == NPY_USHORT ? CV_16U : typenum == NPY_SHORT ? CV_16S : typenum == NPY_INT || typenum == NPY_LONG ? CV_32S : typenum == NPY_FLOAT ? CV_32F : typenum == NPY_DOUBLE ? CV_64F : -1; if( type < 0 ) { failmsg("%s data type = %d is not supported", name, typenum); return false; } int ndims = PyArray_NDIM(o); if(ndims >= CV_MAX_DIM) { failmsg("%s dimensionality (=%d) is too high", name, ndims); return false; } int size[CV_MAX_DIM+1]; size_t step[CV_MAX_DIM+1], elemsize = CV_ELEM_SIZE1(type); const npy_intp* _sizes = PyArray_DIMS(o); const npy_intp* _strides = PyArray_STRIDES(o); bool transposed = false; for(int i = 0; i < ndims; i++) { size[i] = (int)_sizes[i]; step[i] = (size_t)_strides[i]; } if( ndims == 0 || step[ndims-1] > elemsize ) { size[ndims] = 1; step[ndims] = elemsize; ndims++; } if( ndims >= 2 && step[0] < step[1] ) { std::swap(size[0], size[1]); std::swap(step[0], step[1]); transposed = true; } if( ndims == 3 && size[2] <= CV_CN_MAX && step[1] == elemsize*size[2] ) { ndims--; type |= CV_MAKETYPE(0, size[2]); } if( ndims > 2 && !allowND ) { failmsg("%s has more than 2 dimensions", name); return false; } m = Mat(ndims, size, type, PyArray_DATA(o), step); if( m.data ) { m.refcount = refcountFromPyObject(o); m.addref(); // protect the original numpy array from deallocation // (since Mat destructor will decrement the reference counter) }; m.allocator = &g_numpyAllocator; if( transposed ) { Mat tmp; tmp.allocator = &g_numpyAllocator; transpose(m, tmp); m = tmp; } return true; } static PyObject* pyopencv_from(const Mat& m) { if( !m.data ) Py_RETURN_NONE; Mat temp, *p = (Mat*)&m; if(!p->refcount || p->allocator != &g_numpyAllocator) { temp.allocator = &g_numpyAllocator; m.copyTo(temp); p = &temp; } p->addref(); return pyObjectFromRefcount(p->refcount); } My python test program: import pysomemodule # My python wrapped library. import cv2 def main(): myobj = pysomemodule.ABC("faces.train") # Create python object. This works. image = cv2.imread('61.jpg') processedImage = myobj.doSomething(image) cv2.imshow("test", processedImage) cv2.waitKey() if __name__ == "__main__": main()

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  • What is the MVC version of this code?

    - by Ian Boyd
    i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes. i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version? Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered: private void txtLastname_TextChanged(object sender, EventArgs e) { //Lastname mandatory. //Color pinkish if nothing entered. Greenish if entered. if (txtLastname.Text.Trim() == "") { //Lastname is required, color pinkish txtLastname.BackColor = ControlBad; } else { //Lastname entered, remove the coloring txtLastname.BackColor = ControlGood; } } Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field: private void txtFirstname_TextChanged(object sender, EventArgs e) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (txtFirstname.Text == "") { //Nothing there, hint it blue txtFirstname.BackColor = ControlRequired; } else if (txtFirstname.Text.Trim() == "") { //They entered spaces - bad user! txtFirstname.BackColor = ControlBad; } else { //Entered stuff, remove coloring txtFirstname.BackColor = SystemColors.Window; } } Example 3 The age is totally optional. If an age is entered, it better be valid: private void txtAge_TextChanged(object sender, EventArgs e) { //Age is optional, but if entered it better be valid int nAge = 0; if (Int32.TryParse(txtAge.Text, out nAge)) { //Valid integer entered if (nAge < 0) { //Negative age? i don't think so txtAge.BackColor = ControlBad; } else { //Valid age entered, remove coloring txtAge.BackColor = SystemColors.Window; } } else { //Whatever is in there: it's *not* a valid integer, if (txtAge.Text == "") { //Blank is okay txtAge.BackColor = SystemColors.Window; } else { //Not a valid age, bad user txtAge.BackColor = ControlBad; } } } Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help. The model is your data. The view shows data on screen. The controller is used to carry out the users actions And oranges taste orangy. Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC? private void txtFirstname_TextChanged(object sender, EventArgs e) { FirstnameTextChangedHandler(sender, e); } private void FirstnameTextChangedHandler(sender, e) { string firstname = GetFirstname(); Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname); SetFirstNameTextBoxColor(firstnameTextBoxColor); } private string GetFirstname() { return txtFirstname.Text; } private Color GetFirstnameTextBoxColor(string firstname) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (firstname == "") { //Nothing there, hint it blue return GetControlRequiredColor(); } else if (firstname.Trim() == "") { //They entered spaces - bad user! return GetControlBadColor(); } else { //Entered stuff, remove coloring return GetControlDefaultColor(); } } private Color GetControlRequiredColor() { return ControlRequired; } private Color GetControlBadColor() { return ControlBad; } private Color GetControlGoodColor() { return ControlGood; } //am i doin it rite i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files. It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation? Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.

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  • fatal: git-http-push-failed (return code 22)

    - by Mariusz
    Hello, that's me again. After having problem with estabilishing connection to github.com now I have a problem with next step - pushing. I need to mention, that I am novice at GIT service, and this whole Distributed Subversion Checking Systems world.. I have done git init, then git add *.h and git add *.cpp, but currently git status does not print anything in "# On branch master" section? Previously It was correctly printing whole list of added files, now this list is gone. Nextly, I have executed: git remote add origin https://github.com/mgeeky/disasm.git and error has occured after: git push origin master Username: Password: error: Cannot access URL https://github.com/mgeeky/disasm.git/, return code 22 fatal: git-http-push failed What should I do now? I've tried: git push origin Username: Password: No refs in common and none specified; doing nothing. Perhaps you should specify a branch such as 'master'. Everything up-to-date But it seems to be okey.

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  • Group Policy drive maps fail with Error Code: 0x80070043

    - by Topherhead
    I'm running a Server 2008 R2 domain with all Windows 7 x64 bit client machines. All drives are mapped using Group Policy. Which were previously on a NAS We just built a new, huge, fast server. So I'm in the process of migrating all the network drives from the NAS to the new fileserver(fs). The old drive maps were mapped using group policy so I just went in and updated to the new server and selected the "Replace" option. But the drives just plain do not map. I do an RSOP on my machine and the error for the drive map is: Result: Failure (Error Code: 0x80070043) The other odd thing, though it may or may not have anything to do with it, is that the winning GPO shown is shown with its SID instead of its name. The SID is correct though. Accessing the shares through Explorer works fine, and mapping them manually works fine. Any ideas? Thanks Chris

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  • Sharepoint 2007: author.dll status code?

    - by CrazyNick
    Is there a way to find any info using /_vti_bin/_vti_aut /author.dll status code? <html><head><title>vermeer RPC packet</title></head> <body> <p>method= <p>status= <ul> <li>status=393226 <li>osstatus=0 <li>msg=The form submission cannot be processed because it exceeded the maximum length allowed by the Web administrator. Please resubmit the form with less data. <li>osmsg= </ul> </body> </html>

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  • updating from windows 8 to windows 8.1 give me error 0x101 0x2000c and driver irql not less or equal on clean install

    - by user1143745
    i'm trying to update my hp dv6-6156sl running win 8 to win 8.1. When i try to update the os with all kept when it configures devices (around 55%) i get a bsod with driver irql not less or equal error and windows revert back to my previous windows 8 showing at the end 0x101 0x2000c error. So i tried a clean install to see if i could fix it but i still get the same driver irql not less or equal error (on ntoskrnl.exe) I tried to edit bios settings to see if there's something to disable but like almost all hp laptops it is locked so i can only enable virtualization, select boot order and change gpu between fixed or dinamic (none of these worked) i found the dmp file with the error of the update: https://dl.dropboxusercontent.com/u/2219086/setupmem.dmp How can i fix this?

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  • hp ProLiant DL380 G6 server error code: 347 of array controller

    - by alhaythum
    I have got a bran new hp ProLiant DL380 G6 server with embedded smart array P410i controller, I got 164 GB SATA drives and wanted to change them with 300 GB SATA drives before installation. Now, we replace the drives and begin the configuration with the hp DVD and begin; when we reach the point that we want to save the configurations, an error message appears: "The operation has failed with an unknown error, please restart the application and attempt the operation again" When using Rescan System, this error message appears: "Status Alerts - Smart Array P410i in Embedded Slot Warning Status Message Code Description 347 The cache for Smart Array P410i Embedded Slot is not configured" We return back to the 164 GB SATA drives and the message just keeps appearing again. Any help please.

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  • website uses an invalid security certificate (Error code: ssl_error_bad_cert_domain)

    - by Walter Lockhart
    I am running IIS 7 on Windows Server 2008. I have two websites: www.website01.com www.website02.com I have an SSL Certificate for each website. When I access a secured page on www.website02.com I get the error: www.website02.com uses an invalid security certificate. The certificate is only valid for www.website01.com. (Error code: ssl_error_bad_cert_domain) I have googled this error and I understand that it is caused by the fact that I have bound both sites to the same IP Address / Port No. (443). However, I don't know what I need to do to remedy this situation. Would someone please help. Thanks in advance. Kind Regards Walter

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  • How can I clean up my bashrc/zshrc file?

    - by LuxuryMode
    Over time, I've added bunches of stuff to my PATH and it's lookin' pretty awful. How can I clean this up or what's the proper way to "reformat" all of this? export PATH="$PATH:~/scripts" export PATH="$PATH:~/Downloads/android-sdk-mac_x86/platform-tools/adb" export PATH=/opt/local/bin:/opt/local/sbin:$PATH export PATH="$PATH:~/Downloads/android-sdk-mac_x86/platform-tools:~/Downloads/android-sdk-mac_x86/tools:~/Downloads/android-sdk-mac_x86/platform-tools/adb" export PATH="$PATH:~/bin" export PATH="$PATH:~/bin/subl" export PATH="$PATH:~/.rvm/gems/ruby-1.9.3-head/gems/git-media-0.1.1/bin" export PATH=$PATH:$HOME/bin:/Users/me/Downloads/android-sdk-mac_86/tools export PATH=$PATH:$HOME/bin:/Users/me/Downloads/android-sdk-mac_86/platform-tools export PATH=/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/X11/bin:/.rvm/scripts/rvm:/.rvm/scripts/rvm:/~/Downloads/android-sdk-mac_x86/tools/android:/~/Downloads/android-ndk-r7/:/~/Downloads/android-sdk-mac_x86/platform-tools export CC=gcc-4.2 export PATH=~/Downloads/android-ndk-r7:$PATH ANDROID_HOME=~/Downloads/android-sdk-mac_x86 export PATH=${PATH}:$ANDROIDHOME/platform-tools

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  • Remote Desktop closes with Fatal Error (Error Code: 5)

    - by Swinders
    We have one PC (Windows XP SP3) that we can not log onto using a Remote Desktop session. Logging on to the PC directly (sitting in front of it using the connected keyboard and monitor) work fine. From a second PC (tried a number of different ones but all Windows XP SP3) I run 'mstsc' and type in PC name to connect to. This shows the login box which we can enter the correct login details and click OK. Within a few second we get an error: Title: Fatal Error (Error Code:5) Error: Your Remote Desktop session is about to end. This computer might be low on virtual memory. Close your other programs, and then try connecting to the remote computer again. If the problem continues, contact your network administrator or technical support. None of the computers we are using are low on memory (2Gb+) and we let windows manage the virtual memory side of things. We do not see this with any other PC and do use Remote Desktop in meeting rooms to connect to user PCs with no problems.

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  • Prevent apache http server changing response code

    - by Brad
    Hi all, I have a servlet providing a REST based service running on tomcat which I am accessing through Apache Http Server v2.2. My problem is that a response code for one for the service methods is being changed when it passes through http server. I have a curl script which I use to test the service. It is supposed to return a 204 No content response which it does when I hit the servlet directly. When I hit Apache with the script the response gets changed to a 200 Ok. Can anyone with experience of configuring Apache advise me how to fix this? Thanks, Brad.

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  • Unable to understand a line in Google CodePreview's README

    - by Masi
    The README is in Google's codepreview which uses Google-appengine. To run the app locally (e.g. for testing), download the Google App Engine SDK from http://code.google.com/appengine/downloads.html. You can then run the server using make serve I run make serve in my terminal after moving Google-appengine.app to my Application -folder in OS X Leopard. I get make: *** No rule to make target `serve'. Stop. How can you run the make serve to run the server for Google AppEngine?

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  • Deploying new code live

    - by nicoX
    What's the best practise to deploy new code on a live (e-commerce) site? For now I have stopped apache for +/- 10 seconds when renaming directory public_html_new to public_html and old to public_html_old. This creates a short down-time, before I start Apache again. The same question goes if using Git to pull the new repo to the live directory. Can I pull the repo while the site is active? And how about if I need to copy a DB as well? During the tar (backup purpose) compression of the live site I noticed that changes occurred in the media directory. That indicated to me that files keep on changing periodically. And if these changes can interfere if Apache is not stopped during deployment.

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