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  • What am i doing wrong

    - by Erik Sapir
    I have the following code. I need B class to have a min priority queue of AToTime objects. AToTime have operator, and yet i receive error telling me than there is no operator matching the operands... #include <queue> #include <functional> using namespace std; class B{ //public functions public: B(); virtual ~B(); //private members private: log4cxx::LoggerPtr m_logger; class AToTime { //public functions public: AToTime(const ACE_Time_Value& time, const APtr a) : m_time(time), m_a(a){} bool operator >(const AToTime& other) { return m_time > other.m_time; } //public members - no point using any private members here public: ACE_Time_Value m_time; APtr m_a; }; priority_queue<AToTime, vector<AToTime>, greater<AToTime> > m_myMinHeap; };

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  • Rotate a feature Image in Open Layers - Javascript variable from JSON.

    - by Ozaki
    I have an open layers map. It adds and removes my "imageFeature" every 10secs or so. I have a JSON feed that gives me the rotation that I need, I have a request to get that rotation and set it as a variable of rotationv. Everything works but the fact when the image is recreated it does not update the rotation. My code is as follows: JSON request: var rotationv = (function () { rotationv = null; $.ajax({ 'async': false, 'global': true, 'url': urldefault, 'dataType': "json", 'success': function (data) { rotationv = data.rotation; } }); return rotationv })(); Creating image feature: imageFeature = new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point(mylon, mylat), { rotation: rotationv } ); The image is set in the styling elsewhere. Why does this not rotate my image? Debugging with firebug I now notice that "rotationv" is updating as per it should be. But when the point is destroyed then added again it does not apply the new rotation... Add: I realised that the "image" is applied as per the layer. So I need to figure out how to re apply the stylemap to the layer so it will trigger the "update" on the page. //redefine layer 2 so it can be updated// //test.js is just a 0.0 testref// var layer2 = new OpenLayers.Layer.GML("Layer 2", "test.js", { format: OpenLayers.Format.GeoJSON, styleMap: styleMap }); But even if I add the above into my function still no luck. Included map.addLayers([layer2]); into the function as well.

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  • Code bacteria: evolving mathematical behavior

    - by Stefano Borini
    It would not be my intention to put a link on my blog, but I don't have any other method to clarify what I really mean. The article is quite long, and it's in three parts (1,2,3), but if you are curious, it's worth the reading. A long time ago (5 years, at least) I programmed a python program which generated "mathematical bacteria". These bacteria are python objects with a simple opcode-based genetic code. You can feed them with a number and they return a number, according to the execution of their code. I generate their genetic codes at random, and apply an environmental selection to those objects producing a result similar to a predefined expected value. Then I let them duplicate, introduce mutations, and evolve them. The result is quite interesting, as their genetic code basically learns how to solve simple equations, even for values different for the training dataset. Now, this thing is just a toy. I had time to waste and I wanted to satisfy my curiosity. however, I assume that something, in terms of research, has been made... I am reinventing the wheel here, I hope. Are you aware of more serious attempts at creating in-silico bacteria like the one I programmed? Please note that this is not really "genetic algorithms". Genetic algorithms is when you use evolution/selection to improve a vector of parameters against a given scoring function. This is kind of different. I optimize the code, not the parameters, against a given scoring function.

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  • Pass a data.frame column name to a function

    - by Kevin Middleton
    I'm trying to write a function to accept a data.frame (x) and a column from it. The function performs some calculations on x and later returns another data.frame. I'm stuck on the best-practices method to pass the column name to the function. The two minimal examples fun1 and fun2 below produce the desired result, being able to perform operations on x$column, using max() as an example. However, both rely on the seemingly (at least to me) inelegant (1) call to substitute() and possibly eval() and (2) the need to pass the column name as a character vector. fun1 <- function(x, column){ do.call("max", list(substitute(x[a], list(a = column)))) } fun2 <- function(x, column){ max(eval((substitute(x[a], list(a = column))))) } df <- data.frame(A = 1:20, B = rnorm(10)) fun1(df, "B") fun2(df, "B") I would like to be able to call the function as fun(df, B), for example. Other options I have considered but have not tried: Pass column as an integer of the column number. I think this would avoid substitute(). Ideally, the function could accept either. with(x, get(column)), but, even if it works, I think this would still require substitute Make use of formula() and match.call(), neither of which I have much experience with. Subquestion: Is do.call() preferred over eval()? Thanks, Kevin

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  • Saving "heavy" figure to PDF in MATLAB - rendering problem

    - by yuk
    I generate a figure in MATLAB with lot amount of points (100000+) and want to save it into a PDF file. With zbuffer or painters renderer I've got very large and slowly opened file (over 4 Mb) - all points are in vector format. Using OpenGL renderer rasterize the figure in PDF, ok for the plot, but not good for text labels. The file size is about 150 Kb. Try this simplified code, for example: x=linspace(1,10,100000); y=sin(x)+randn(size(x)); plot(x,y,'.') set(gcf,'Renderer','zbuffer') print -dpdf -r300 testpdf_zb set(gcf,'Renderer','painters') print -dpdf -r300 testpdf_pa set(gcf,'Renderer','opengl') print -dpdf -r300 testpdf_op The actual figure is much more complex with several axes and different types of plots. Is there a way to rasterize the figure, but keep text labels as vectors? Another problem with OpenGL is that is does not work in terminal mode (-nosplash -nodesktop) under Mac OSX. Looks like OpenGL is not supported. I have to use terminal mode for automation. The MATLAB version I run is 2007b. Mac OSX server 10.4.

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  • How can I apply a PSSM efficiently?

    - by flies
    I am fitting for position specific scoring matrices (PSSM aka Position Specific Weight Matrices). The fit I'm using is like simulated annealing, where I the perturb the PSSM, compare the prediction to experiment and accept the change if it improves agreement. This means I apply the PSSM millions of times per fit; performance is critical. In my particular problem, I'm applying a PSSM for an object of length L (~8 bp) at every position of a DNA sequence of length M (~30 bp) (so there are M-L+1 valid positions). I need an efficient algorithm to apply a PSSM. Can anyone help improve performance? My best idea is to convert the DNA into some kind of a matrix so that applying the PSSM is matrix multiplication. There are efficient linear algebra libraries out there (e.g. BLAS), but I'm not sure how best to turn an M-length DNA sequence into a matrix M x 4 matrix and then apply the PSSM at each position. The solution needs to work for higher order/dinucleotide terms in the PSSM - presumably this means representing the sequence-matrix for mono-nucleotides and separately for dinucleotides. My current solution iterates over each position m, then over each letter in word from m to m+L-1, adding the corresponding term in the matrix. I'm storing the matrix as a multi-dimensional STL vector, and profiling has revealed that a lot of the computation time is just accessing the elements of the PSSM (with similar performance bottlenecks accessing the DNA sequence). If someone has an idea besides matrix multiplication, I'm all ears.

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  • int considered harmful?

    - by Chris Becke
    Working on code meant to be portable between Win32 and Win64 and Cocoa, I am really struggling to get to grips with what the @#$% the various standards committees involved over the past decades were thinking when they first came up with, and then perpetuated, the crime against humanity that is the C native typeset - char, short, int and long. On the one hand, as a old-school c++ programmer, there are few statements that were as elegant and/or as simple as for(int i=0; i<some_max; i++) but now, it seems that, in the general case, this code can never be correct. Oh sure, given a particular version of MSVC or GCC, with specific targets, the size of 'int' can be safely assumed. But, in the case of writing very generic c/c++ code that might one day be used on 16 bit hardware, or 128, or just be exposed to a particularly weirdly setup 32/64 bit compiler, how does use int in c++ code in a way that the resulting program would have predictable behavior in any and all possible c++ compilers that implemented c++ according to spec. To resolve these unpredictabilities, C99 and C++98 introduced size_t, uintptr_t, ptrdiff_t, int8_t, int16_t, int32_t, int16_t and so on. Which leaves me thinking that a raw int, anywhere in pure c++ code, should really be considered harmful, as there is some (completely c++xx conforming) compiler, thats going to produce an unexpected or incorrect result with it. (and probably be a attack vector as well)

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  • How to modify/replace option set file when building from command line?

    - by Heinrich Ulbricht
    I build packages from a batch file using commands like: msbuild ..\lib\Package.dproj /target:Build /p:config=%1 The packages' settings are dependent on an option set: <Import Project="..\optionsets\COND_Defined.optset" Condition="'$(Base)'!='' And Exists('..\optionsets\COND_Defined.optset')"/> This option set defines a conditional symbol many of my packages depend on. The file looks like this: <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <PropertyGroup> <DCC_Define>CONDITION;$(DCC_Define)</DCC_Define> </PropertyGroup> <ProjectExtensions> <Borland.Personality>Delphi.Personality.12</Borland.Personality> <Borland.ProjectType>OptionSet</Borland.ProjectType> <BorlandProject> <Delphi.Personality/> </BorlandProject> <ProjectFileVersion>12</ProjectFileVersion> </ProjectExtensions> </Project> Now I need two builds: one with the condition defined and one without. My attack vector would be the option set file. I have some ideas on what to do: write a program which modifies the option set file, run this before batch build fiddle with the project files and modify the option set path to contain an environment variable, then have different option sets in different locations But before starting to reinvent the wheel I'd like to ask how you would tackle this task? Maybe there are already means meant to support such a case (like certain command line switches, things I could configure in Delphi or batch file magic).

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  • Save PyML.classifiers.multi.OneAgainstRest(SVM()) object?

    - by Michael Aaron Safyan
    I'm using PYML to construct a multiclass linear support vector machine (SVM). After training the SVM, I would like to be able to save the classifier, so that on subsequent runs I can use the classifier right away without retraining. Unfortunately, the .save() function is not implemented for that classifier, and attempting to pickle it (both with standard pickle and cPickle) yield the following error message: pickle.PicklingError: Can't pickle : it's not found as __builtin__.PySwigObject Does anyone know of a way around this or of an alternative library without this problem? Thanks. Edit/Update I am now training and attempting to save the classifier with the following code: mc = multi.OneAgainstRest(SVM()); mc.train(dataset_pyml,saveSpace=False); for i, classifier in enumerate(mc.classifiers): filename=os.path.join(prefix,labels[i]+".svm"); classifier.save(filename); Notice that I am now saving with the PyML save mechanism rather than with pickling, and that I have passed "saveSpace=False" to the training function. However, I am still gettting an error: ValueError: in order to save a dataset you need to train as: s.train(data, saveSpace = False) However, I am passing saveSpace=False... so, how do I save the classifier(s)? P.S. The project I am using this in is pyimgattr, in case you would like a complete testable example... the program is run with "./pyimgattr.py train"... that will get you this error. Also, a note on version information: [michaelsafyan@codemage /Volumes/Storage/classes/cse559/pyimgattr]$ python Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type "help", "copyright", "credits" or "license" for more information. import PyML print PyML.__version__ 0.7.0

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  • Compiling and using NTL c++ library for Windows

    - by Martin Lauridsen
    Hi there, I have compiled the NTL inifite precision integer arithmetic library for c++, using Microsoft Visual Studio 2008. I did as explained, on this site, using the Visual Studio interface, rather than from the command prompt. Actually I would rather do it from the command prompt, but I was not sure how to. Anyhow, I got the library compiled, and I now want to compile a program using the library, from the command prompt. The program I am trying to compile, has been tested on a linux system, where I compile it with the following c++ -I/appl/htopopt/Linux_x86_64/NTL-5.4.2/include mpqs.cpp main.cpp -o main -L/appl/htopopt/Linux_x86_64/NTL-5.4.2/lib -lntl -L/appl/htopopt/Linux_x86_64/gmp-4.2.1/lib -lgmp -lm Nevermind the gmp stuff, I dont have that installed on Windows. It is purely an optional thing that will make the NTL run faster. Anyhow, this works fine on linux. Now on Windows I write the following cl /EHsc /I D:\Downloads\WinNTL-5_5_2\include mpqs.cpp main.cpp /link /LIBPATH:"D:\Documents\Visual Studio 2008\Projects\ntl\Debug" But this results in the following errors: mpqs.cpp mpqs.cpp(38) : error C2039: 'find_smooth_vals' : is not a member of 'QS' d:\desktop\qs\mpqs.h(12) : see declaration of 'QS' mpqs.cpp(41) : error C2065: 'M' : undeclared identifier mpqs.cpp(41) : error C2065: 'n' : undeclared identifier mpqs.cpp(42) : error C2065: 'sieve_table' : undeclared identifier mpqs.cpp(42) : error C2228: left of '.size' must have class/struct/union type is ''unknown-type'' mpqs.cpp(43) : error C2065: 'sieve_table' : undeclared identifier mpqs.cpp(44) : error C2065: 'qx_table' : undeclared identifier mpqs.cpp(44) : error C3861: 'test_smoothness': identifier not found mpqs.cpp(45) : error C2065: 'smooth_indices' : undeclared identifier mpqs.cpp(45) : error C2228: left of '.push_back' must have class/struct/union type is ''unknown-type'' main.cpp Generating Code... It is as if, my mpqs.h file is not included into the compilation process? Also I dont understand why it complains about .push_back() for a vector type? Help is much appreciated!

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  • R:how to get grep to return the match, rather than the whole string

    - by Mike Dewar
    Hi, I have what is probably a really dumb grep in R question. Apologies, because this seems like it should be so easy - I'm obviously just missing something. I have a vector of strings, let's call it alice. Some of alice is printed out below: T.8EFF.SP.OT1.D5.VSVOVA#4 T.8EFF.SP.OT1.D6.LISOVA#1 T.8EFF.SP.OT1.D6.LISOVA#2 T.8EFF.SP.OT1.D6.LISOVA#3 T.8EFF.SP.OT1.D6.VSVOVA#4 T.8EFF.SP.OT1.D8.VSVOVA#3 T.8EFF.SP.OT1.D8.VSVOVA#4 T.8MEM.SP#1 T.8MEM.SP#3 T.8MEM.SP.OT1.D106.VSVOVA#2 T.8MEM.SP.OT1.D45.LISOVA#1 T.8MEM.SP.OT1.D45.LISOVA#3 I'd like grep to give me the number after the D that appears in some of these strings, conditional on the string containing "LIS" and an empty string or something otherwise. I was hoping that grep would return me the value of a capturing group rather than the whole string. Here's my R-flavoured regexp: pattern <- (?<=\\.D)([0-9]+)(?=.LIS) nothing too complicated. But in order to get what I'm after, rather than just using grep(pattern, alice, value = TRUE, perl = TRUE) I'm doing the following, which seems bad: reg.out <- regexpr( "(?<=\\.D)[0-9]+(?=.LIS)", alice, perl=TRUE ) substr(alice,reg.out,reg.out + attr(reg.out,"match.length")-1) Looking at it now it doesn't seem too ugly, but the amount of messing about it's taken to get this utterly trivial thing working has been embarrassing. Anyone any pointers about how to go about this properly? Bonus marks for pointing me to a webpage that explains the difference between whatever I access with $,@ and attr.

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  • Possible to rank partial matches in Postgres full text search?

    - by Joe
    I'm trying to calculate a ts_rank for a full-text match where some of the terms in the query may not be in the ts_vector against which it is being matched. I would like the rank to be higher in a match where more words match. Seems pretty simple? Because not all of the terms have to match, I have to | the operands, to give a query such as to_tsquery('one|two|three') (if it was &, all would have to match). The problem is, the rank value seems to be the same no matter how many words match. In other words, it's maxing rather than multiplying the clauses. select ts_rank('one two three'::tsvector, to_tsquery('one')); gives 0.0607927. select ts_rank('one two three'::tsvector, to_tsquery('one|two|three|four')); gives the expected lower value of 0.0455945 because 'four' is not the vector. But select ts_rank('one two three'::tsvector, to_tsquery('one|two')); gives 0.0607927 and likewise select ts_rank('one two three'::tsvector, to_tsquery('one|two|three')); gives 0.0607927 I would like the result of ts_rank to be higher if more terms match. Possible? To counter one possible response: I cannot calculate all possible subsequences of the search query as intersections and then union them all in a query because I am going to be working with large queries. I'm sure there are plenty of arguments against this anyway! Edit: I'm aware of ts_rank_cd but it does not solve the above problem.

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  • xmlEncoder not writing in netBeans

    - by Greg
    Hi, I am trying to use the xmlEncoder to write to xml file in net-beans but it doesnt work. Here is the call to the writing function: dbManipulator.writeStudents(deps); where deps = new Hashtable<String, Department>(); dbManipulator = new DataBaseManipulator(); Department is an class-object I made, and here is writeStudents method which is located in the DataBaseManipulator class: public void writeStudents(Hashtable<Integer, Student> students) { XMLEncoder encoder = null; try { encoder = new XMLEncoder(new FileOutputStream(".\\test\\Students.xml")); } catch(Exception e){} encoder.writeObject(students); encoder.close(); }//end of function writeStudents() Any ideas why it isnt working? I tried changing the hashtable to vector but still the xml file looks like that after the writing: <?xml version="1.0" encoding="UTF-8"?> <java version="1.6.0_18" class="java.beans.XMLDecoder"> <object class="java.util.Hashtable"/> </java> Thanks in advance, Greg

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  • JPA native query join returns object but dereference throws class cast exception

    - by masato-san
    I'm using JPQL Native query to join table and query result is stored in List<Object[]>. public String getJoinJpqlNativeQuery() { String final SQL_JOIN = "SELECT v1.bitbit, v1.numnum, v1.someTime, t1.username, t1.anotherNum FROM MasatosanTest t1 JOIN MasatoView v1 ON v1.username = t1.username;" System.out.println("get join jpql native query is being called ============================"); EntityManager em = null; List<Object[]> out = null; try { em = EmProvider.getDefaultManager(); Query query = em.createNativeQuery(SQL_JOIN); out = query.getResultList(); System.out.println("return object ==========>" + out); System.out.println(out.get(0)); String one = out.get(0).toString(); //LINE 77 where ClassCastException System.out.println(one); } catch(Exception e) { } finally { if(em != null) { em.close; } } } The problem is System.out.println("return object ==========>" + out); outputs: return object ==========> [[true, 0, 2010-12-21 15:32:53.0, masatosan, 0.020], [false, 0, 2010-12-21 15:32:53.0, koga, 0.213]] System.out.println(out.get(0)) outputs: [true, 0, 2010-12-21 15:32:53.0, masatosan, 0.020] So I assumed that I can assign return value of out.get(0) which should be String: String one = out.get(0).toString(); But I get weird ClassCastException. java.lang.ClassCastException: java.util.Vector cannot be cast to [Ljava.lang.Object; at local.test.jaxrs.MasatosanTestResource.getJoinJpqlNativeQuery (MasatosanTestResource.java:77) So what's really going on? Even Object[] foo = out.get(0); would throw an ClassCastException :(

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  • R: outlier cleaning for each column in a dataframe by using quantiles 0.05 and 0.95

    - by Rainer
    hi, I am a R-novice. I want to do some outlier cleaning and over-all-scaling from 0 to 1 before putting the sample into a random forest. g<-c(1000,60,50,60,50,40,50,60,70,60,40,70,50,60,50,70,10) If i do a simple scaling from 0 - 1 the result would be: > round((g - min(g))/abs(max(g) - min(g)),1) [1] 1.0 0.1 0.0 0.1 0.0 0.0 0.0 0.1 0.1 0.1 0.0 0.1 0.0 0.1 0.0 0.1 0.0 So my idea is to replace the values of each column that are greater than the 0.95-quantile with the next value smaller than the 0.95-quantile - and the same for the 0.05-quantile. So the pre-scaled result would be: g<-c(**70**,60,50,60,50,40,50,60,70,60,40,70,50,60,50,70,**40**) and scaled: > round((g - min(g))/abs(max(g) - min(g)),1) [1] 1.0 0.7 0.3 0.7 0.3 0.0 0.3 0.7 1.0 0.7 0.0 1.0 0.3 0.7 0.3 1.0 0.0 I need this formula for a whole dataframe, so the functional implementation within R should be something like: > apply(c, 2, function(x) x[x`<quantile(x, 0.95)]`<-max(x[x, ... max without the quantile(x, 0.95)) Can anyone help? Spoken beside: if there exists a function that does this job directly, please let me know. I already checked out cut and cut2. cut fails because of not-unique breaks; cut2 would work, but only gives back string values or the mean value, and I need a numeric vector from 0 - 1. for trial: a<-c(100,6,5,6,5,4,5,6,7,6,4,7,5,6,5,7,1) b<-c(1000,60,50,60,50,40,50,60,70,60,40,70,50,60,50,70,10) c<-cbind(a,b) c<-as.data.frame(c) Regards and thanks for help, Rainer

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  • error with std::ostringsteam and std::string

    - by pyCthon
    Hi i want to save many different csv files from a function with a naming convention based on a different double value. I do this with a for loop and pass a string value to save each .csv file differently. Below is an example of what I'm trying to do the desired result would be 1.1_file.csv 1.2_file.csv but instead i get 1.1_file.csv 1.11.2_file.csv Here is a working sample code, what can i do to fix this #include <sstream> #include <iomanip> #include <cmath> #include <iostream> #include <vector> int main(){ std::string file = "_file.csv"; std::string s; std::ostringstream os; double x; for(int i = 0; i < 10; i++){ x = 0.1 + 0.1 *i; os << std::fixed << std::setprecision(1); os << x; s = os.str(); std::cout<<s+file<<std::endl; s.clear(); } return 0; }

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  • how to convert byte array to image in java?

    - by nemade-vipin
    I am developing a Web application in Java. In that application, I have created webservices in Java. In that webservice, I have created one webmethod which returns the image list in base64 format. The return type of the method is Vector. In webservice tester I can see the SOAP response as xsi:type="xs:base64Binary". Then I called this webmethod in my application. I used the following code: SBTSWebService webService = null; List imageArray = null; List imageList = null; webService = new SBTSWebService(); imageArray = webService.getSBTSWebPort().getAddvertisementImage(); Iterator itr = imageArray.iterator(); while(itr.hasNext()) { String img = (String)itr.next(); byte[] bytearray = Base64.decode(img); BufferedImage imag=ImageIO.read(new ByteArrayInputStream(bytearray)); imageList.add(imag); } In this code I am receiving the error: java.lang.ClassCastException: [B cannot be cast to java.lang.String" on line String img = (String)itr.next(); Is there any mistake in my code? Or is there any other way to bring the image in actual format? Can you provide me the code or link through which I can resolve the above issue? Note:- I already droped this question and I got the suggetion to try the following code Object next = iter.next(); System.out.println(next.getClass()) I tried this code and got the output as byte[] from webservice. but I am not able to convert this byte array to actual image. is there any other way to bring the image in actual format? Can you provide me the code or link through which I can resolve the above issue?

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  • How can I store an inventory-like list of numbers?

    - by Rachel
    I've got a list of number that I need to keep track of. The numbers are loosely related, but represent distinctly different items. I'd like to keep a list of the numbers but be able to refer to them by name so that I can call them and use them where needed easily. Kind of like an inventory listing, where the numbers all refer to a part ID and I'd like to call them idPart1, idPart2, idPart3 so their purpose is easily identifiable when they are used. What would be the best way to do this? 1)Define a structure. Say, PartIds. A number of int members will be included, part1, part2 etc. To use, an instance of the structure will be created, values assigned to the members, and the numbers will be used by saying struct.member as needed. 2)Define an enumeration. Use part1, part2 as the enum literals. Store the actual values in a vector or list, each one at the index corresponding to the value of the number's name within the enum. Use the enum literals to retrieve the values, list[enumLit]. 3)Something completely different There's nothing else I need to do with the numbers - just look them up every once in a while. Since there's no processing, I kind of think a new class for them is overkill, but I'm willing to be convinced otherwise. Any suggestions?

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  • How to create extensible dynamic array in Java without using pre-made classes?

    - by AndrejaKo
    Yeah, it's a homework question, so givemetehkodezplsthx! :) Anyway, here's what I need to do: I need to have a class which will have among its attributes array of objects of another class. The proper way to do this in my opinion would be to use something like LinkedList, Vector or similar. Unfortunately, last time I did that, I got fire and brimstone from my professor, because according to his belief I was using advanced stuff without understanding basics. Now next obvious solution would be to create array with fixed number of elements and add checks to get and set which will see if the array is full. If it is full, they'd create new bigger array, copy older array's data to the new array and return the new array to the caller. If it's mostly empty, they'd create new smaller array and move data from old array to new. To me this looks a bit stupid. For my homework, there probably won't be more that 3 elements in an array, but I'd like to make a scalable solution without manually calculating statistics about how often is array filled, what is the average number of new elements added, then using results of calculation to calculate number of elements in new array and so on. By the way, there is no need to remove elements from the middle of the array. Any tips?

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  • Access Violation in std::pair

    - by sameer karjatkar
    I have an application which is trying to populate a pair. Out of nowhere the application crashes. The Windbg analysis on the crash dump suggests: PRIMARY_PROBLEM_CLASS: INVALID_POINTER_READ DEFAULT_BUCKET_ID: INVALID_POINTER_READ STACK_TEXT: 0389f1dc EPFilter32!std::vector<std::pair<unsigned int,unsigned int>,std::allocator<std::pair<unsigned int,unsigned int> > >::size+0xc INVALID_POINTER_READ_c0000005_Test.DLL!std::vector_std::pair_unsigned_int, unsigned_int_,std::allocator_std::pair_unsigned_int,unsigned_int_____::size Following is the code snap in the code where it fails: for (unsigned i1 = 0; i1 < size1; ++i1) { for (unsigned i2 = 0; i2 < size2; ++i2) { const branch_info& b1 = en1.m_branches[i1]; //Exception here :crash const branch_info& b2 = en2.m_branches[i2]; } } where branch_info is std::pair<unsigned int,unsigned int> and the en1.m_branches[i1] fetches me a pair value.

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  • Algorithm for scoring user activity

    - by ManBugra
    I have an application where users can: Write reviews about products Add comments to products Up / Down vote reviews Up / Down vote comments Every Up/Down vote is recorded in a db table. What i want to do now is to create a ranking of the most active users in the last 4 weeks. Of course good reviews should be weighted more than good comments. But also e.g. 10 good comments should be weighted more than just one good review. Example: // reviews created in recent 4 weeks //format: [ upVoteCount, downVoteCount ] var reviews = [ [120,23], [32,12], [12,0], [23,45] ]; // comments created in recent 4 weeks // format: [ upVoteCount, downVoteCount ] var comments = [ [1,2], [322,1], [0,0], [0,45] ]; // create weight vector // format: [ reviewWeight, commentsWeight ] var weight = [0.60, 0.40]; // signature: activties..., activityWeight var userActivityScore = score(reviews, comments, weight); ... update user table ... List<Users> users = "from users u order by u.userActivityScore desc"; How would a fair scoring function look like? How could an implementation of the score() function look like? How to add a weight g to the function so that reviews are weighted heavier? How would such a function look like if, for example, votes for pictures would be added?

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  • Collapsing data frame by selecing one row per group

    - by jkebinger
    I'm trying to collapse a data frame by removing all but one row from each group of rows with identical values in a particular column. In other words, the first row from each group. For example, I'd like to convert this > d = data.frame(x=c(1,1,2,4),y=c(10,11,12,13),z=c(20,19,18,17)) > d x y z 1 1 10 20 2 1 11 19 3 2 12 18 4 4 13 17 Into this: x y z 1 1 11 19 2 2 12 18 3 4 13 17 I'm using aggregate to do this currently, but the performance is unacceptable with more data: > d.ordered = d[order(-d$y),] > aggregate(d.ordered,by=list(key=d.ordered$x),FUN=function(x){x[1]}) I've tried split/unsplit with the same function argument as here, but unsplit complains about duplicate row numbers. Is rle a possibility? Is there an R idiom to convert rle's length vector into the indices of the rows that start each run, which I can then use to pluck those rows out of the data frame?

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  • Moving inserted container element if possible

    - by doublep
    I'm trying to achieve the following optimization in my container library: when inserting an lvalue-referenced element, copy it to internal storage; but when inserting rvalue-referenced element, move it if supported. The optimization is supposed to be useful e.g. if contained element type is something like std::vector, where moving if possible would give substantial speedup. However, so far I was unable to devise any working scheme for this. My container is quite complicated, so I can't just duplicate insert() code several times: it is large. I want to keep all "real" code in some inner helper, say do_insert() (may be templated) and various insert()-like functions would just call that with different arguments. My best bet code for this (a prototype, of course, without doing anything real): #include <iostream> #include <utility> struct element { element () { }; element (element&&) { std::cerr << "moving\n"; } }; struct container { void insert (const element& value) { do_insert (value); } void insert (element&& value) { do_insert (std::move (value)); } private: template <typename Arg> void do_insert (Arg arg) { element x (arg); } }; int main () { { // Shouldn't move. container c; element x; c.insert (x); } { // Should move. container c; c.insert (element ()); } } However, this doesn't work at least with GCC 4.4 and 4.5: it never prints "moving" on stderr. Or is what I want impossible to achieve and that's why emplace()-like functions exist in the first place?

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  • Elegant way of parsing Data files for Simulation

    - by sc_ray
    I am working on this project where I need to read in a lot of data from .dat files and use the data to perform simulations. The data in my .dat file looks as follows: DeviceID InteractingDeviceID InteractionStartTime InteractionEndTime 1 2 1101 1105 1,2 1101 and 1105 are tab delimited and it means Device 1 interacted with Device 2 at 1101 ms and ended the interaction at 1105ms. I have a trace data sets that compile thousands of such interactions and my job is to analyze these interactions. The first step is to parse the file. The language of choice is C++. The approach I was thinking of taking was to read the file, for every line that's read create a Device Object. This Device object will contain the property DeviceId and an array/vector of structs, that will contain a list of all the devices the given DeviceId interacted with over the course of the simulation.The struct will contain the Interacting Device Id, Interaction Start Time and Interaction End Time. I have a two fold question here: Is my approach correct? If I am on the right track, how do I rapidly parse these tab delimited data files and create Device objects without excessive memory overhead using C++? A push in the right direction will be much appreciated. Thanks

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  • Trouble with applying a nested loop on a list

    - by user1665355
    I have a list consisting of 3 elements: datalist=list(a=datanew1,b=datanew2,c=datanew3) datalist$a : Inv_ret Firm size leverage Risk Liquidity Equity 17 0.04555968 17.34834 0.1323199 0.011292273 0.02471489 0 48 0.01405835 15.86315 0.6931730 0.002491093 0.12054914 0 109 0.04556252 16.91602 0.1714068 0.006235836 0.01194579 0 159 0.04753472 14.77039 0.3885720 0.007126830 0.06373028 0 301 0.03941040 16.94377 0.1805346 0.005450653 0.01723319 0 datalist$b : Inv_ret Firm size leverage Risk Liquidity Equity 31 0.04020832 18.13300 0.09326265 0.015235240 0.01579559 0.005025379 62 0.04439078 17.84086 0.11016402 0.005486982 0.01266566 0.006559096 123 0.04543250 18.00517 0.12215307 0.011154742 0.01531451 0.002282790 173 0.03960613 16.45457 0.10828643 0.011506857 0.02385191 0.009003780 180 0.03139643 17.57671 0.40063094 0.003447233 0.04530395 0.000000000 datalist$c : Inv_ret Firm size leverage Risk Liquidity Equity 92 0.03081029 19.25359 0.10513159 0.01635201 0.025760806 0.000119744 153 0.03280746 19.90229 0.11731517 0.01443786 0.006769735 0.011999005 210 0.04655847 20.12543 0.11622403 0.01418010 0.003125632 0.003802365 250 0.03301018 20.67197 0.13208234 0.01262499 0.009418828 0.021400052 282 0.04355975 20.03012 0.08588316 0.01918129 0.004213846 0.023657440 I am trying to create a cor.test on the datalist above : Cor.tests=sapply(datalist,function(x){ for(h in 1:length(names(x))){ for(i in 1:length(names(x$h[i]))){ for(j in 1:length(names(x$h[j]))){ cor.test(x$h[,i],x$h[,j])$p.value }}}}) But I get an error : Error in cor.test.default(x$h[, i], x$h[, j]) : 'x' must be a numeric vector Any suggestions about what I am doing wrong? P.S. If I simply have one dataframe, datanew1 : Inv_ret Firm size leverage Risk Liquidity Equity 17 0.04555968 17.34834 0.1323199 0.011292273 0.02471489 0 48 0.01405835 15.86315 0.6931730 0.002491093 0.12054914 0 109 0.04556252 16.91602 0.1714068 0.006235836 0.01194579 0 159 0.04753472 14.77039 0.3885720 0.007126830 0.06373028 0 301 0.03941040 16.94377 0.1805346 0.005450653 0.01723319 0 I use this loop : results=matrix(NA,nrow=6,ncol=6) for(i in 1:length(names(datanew1))){ for(j in 1:length(names(datanew1))){ results[i,j]<-cor.test(datanew1[,i],datanew1[,j])$p.value }} And the output is: results : [,1] [,2] [,3] [,4] [,5] [,6] [1,] 0.000000e+00 7.085663e-09 3.128975e-10 3.018239e-02 4.806400e-10 0.475139526 [2,] 7.085663e-09 0.000000e+00 2.141581e-21 0.000000e+00 2.247825e-20 0.454032499 [3,] 3.128975e-10 2.141581e-21 0.000000e+00 2.485924e-25 2.220446e-16 0.108643838 [4,] 3.018239e-02 0.000000e+00 2.485924e-25 0.000000e+00 5.870007e-15 0.006783324 [5,] 4.806400e-10 2.247825e-20 2.220446e-16 5.870007e-15 0.000000e+00 0.558827862 [6,] 4.751395e-01 4.540325e-01 1.086438e-01 6.783324e-03 5.588279e-01 0.000000000 Which is exactly what I want. But I want to get 3 matrices, one for each element of the datalist above.

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