March 2012 - Boost-users - lists.preview.boost.org

Boost.Factory argument by reference
by gast128 26 Mar '12

26 Mar '12

Hello all, does anyone know if Boost.Factory can be tweaked to use const& instead of references, e.g.: struct Bla { Bla(int n){} }; void Foo() { boost::factory<Bla*> fac; int i = 1; boost::scoped_ptr<KTestBase> ptr2(fac(i)); boost::scoped_ptr<KTestBase> ptr2(fac(2)); //compile error }

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Mystery exception.
by Ted Byers 26 Mar '12

26 Mar '12

Here is a simple unit test. #include <iostream> #include <vector> #include "data.generator.h" #include "reg.class.h" #include <boost/smart_ptr/shared_ptr.hpp> int main(int argc, char* argv[]) { basicGenerator bg; std::cout << "Sample size: " << bg.get_sampleSize() << std::endl; bg.makeData(); std::vector<std::vector<double> > x; std::vector<double> y; bg.getDataForRegression(x,y); unsigned int imax = y.size(); for (unsigned int i = 0 ; i < imax ; i++) { std::cout << i << "\t" << y[i] << "\t" << x[i][0] << "\t" << x[i][1] << std::endl; } std::cout << "==================================================================" << std::endl; regressionPCA rpca(x,y); std::cout << "==================================================================" << std::endl; boost::shared_ptr<regressionPCA> prpca; for (unsigned int j = 0 ; j < 25 ; j++) { std::cout << std::endl << std::endl << "Run #: " << (j + 1) << std::endl; bg.makeData(); bg.getDataForRegression(x,y); /* for (unsigned int i = 0 ; i < imax ; i++) { std::cout << i << "\t" << y[i] << "\t" << x[i][0] << "\t" << x[i][1] << std::endl; }*/ prpca.reset(new regressionPCA(x,y)); std::cout << "==================================================================" << std::endl; } return 0; } The mystery is why I get the following output: 86 -0.727354 -0.252937 -0.841919 87 2.46787 2.13614 1.48789 88 1.79373 1.49828 1.25923 89 0.416356 0.565407 -0.114605 90 -0.258883 -0.585597 -0.183372 91 0.833355 0.914344 0.81171 92 -0.0338814 -0.00264442 -0.118973 93 1.13764 0.41599 1.33175 94 -1.86323 -1.90867 -1.35118 95 0.907604 1.14917 0.621669 96 2.1166 1.06194 1.1703 97 0.159543 0.14446 -0.665135 98 -0.508617 -0.370597 -0.703225 99 2.69086 2.75267 1.40633 ================================================================== r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Sv = 18.3225 4.69155 V = 0.695362 -0.718659 0.718659 0.695362 Beta = 0.693195 0.627794 ================================================================== Run #: 1 r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Sv = 14.1699 10.7091 V = 0.49497 -0.86891 0.86891 0.49497 Beta = 0.476181 0.391545 Aborted (core dumped) Ted@Ted-acer-i7w7 ~/New.System/tests $ I do not know if it is something peculiar to GSL or to my use of either the boost::shared_ptr or the boost::shared_array, but for whatever reason, I get only one analysis out if a given instance of my PCA regression class. Here is how it is declared: #ifndef REG_CLASS_H #define REG_CLASS_H #include <iosfwd> #include <vector> #include <gsl/gsl_linalg.h> class regressionPCA { private: unsigned int nrows, ncols; regressionPCA(void) {}; // makes default construction impossible public: regressionPCA(const std::vector<std::vector<double> >&, const std::vector<double>&); void Reset(const std::vector<std::vector<double> >&, const std::vector<double>&); inline void setNrows(unsigned int v) { nrows = v;}; inline void setNcols(unsigned int v) { ncols = v;}; inline unsigned int getNrows(void) const { return nrows; }; inline unsigned int getNcols(void) const { return ncols; }; }; #endif And here is how it is implemented: #include "reg.class.h" #include <iostream> #include <algorithm> #include <gsl/gsl_linalg.h> #include <boost/smart_ptr/shared_array.hpp> regressionPCA::regressionPCA(const std::vector<std::vector<double> >&data, const std::vector<double>& Ydata) { Reset(data,Ydata); } void regressionPCA::Reset(const std::vector<std::vector<double> >&data, const std::vector<double>& Ydata) { unsigned int r(0),c(0),n(0); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; r = data.size(); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; c = data[0].size(); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; setNrows(r); setNcols(c); n = r * c; std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; /* */ boost::shared_array<double> Btmp(new double[c]), Ytmp(new double[r]), Utmp(new double[n]), Vtmp(new double[c*c]), Stmp(new double[c]); double* B = Btmp.get(); double* Y = Ytmp.get(); double* U = Utmp.get(); double* V = Vtmp.get(); double* S = Stmp.get(); /* */ /* double* B = new double[c]; double* Y = new double[r]; double* U = new double[n]; double* V = new double[c*c]; double* S = new double[c]; */ // double *bptr = U.get(); double *bptr = U; std::vector<std::vector<double> >::const_iterator it = data.begin(), end = data.end(); while (it != end) { bptr = std::copy(it->begin(), it->end(),bptr); ++it; } bptr = Y; std::copy(Ydata.begin(),Ydata.end(),bptr); gsl_matrix_view Um = gsl_matrix_view_array(U, getNrows(), getNcols()); gsl_vector_view Ym = gsl_vector_view_array(Y, getNrows()); gsl_vector_view Bm = gsl_vector_view_array(B, getNcols()); gsl_vector_view Sm = gsl_vector_view_array(S, getNcols()); gsl_matrix_view Vm = gsl_matrix_view_array(V, getNcols(), getNcols()); gsl_linalg_SV_decomp_jacobi(&Um.matrix,&Vm.matrix,&Sm.vector); gsl_linalg_SV_solve(&Um.matrix,&Vm.matrix,&Sm.vector,&Ym.vector,&Bm.vector); std::cout << std::endl << std::endl << "Sv = " << gsl_vector_get(&Sm.vector,0) << "\t" << gsl_vector_get(&Sm.vector,1) << std::endl; std::cout << std::endl << std::endl << "V = " << std::endl; std::cout << "\t" << gsl_matrix_get(&Vm.matrix,0,0) << "\t" << gsl_matrix_get(&Vm.matrix,0,1) << std::endl; std::cout << "\t" << gsl_matrix_get(&Vm.matrix,1,0) << "\t" << gsl_matrix_get(&Vm.matrix,1,1) << std::endl; std::cout << std::endl << std::endl << "Beta = " << gsl_vector_get(&Bm.vector,0) << "\t" << gsl_vector_get(&Bm.vector,1) << std::endl; /* delete[] B; delete[] Y; delete[] U; delete[] V; delete[] S; */ }; NB: It does not matter whether I use naked arrays (and explicitly use operator delete[], or boost::array. Nor does it matter whether I have the instance of it in the loop on the stack or heap (I did make all the work inReset so that the same instance could be used to do all of a series of regressions, but there is little point if I get a core dump). Since I am working with a system that may be non-autonomous, I was going to modify it to work with a boost:: circular_buffer, and then use the std::copy on that container's begin and end iterators in exactly the same way that I use it with the std:;vector above, so I can doing a moving analysis with a fixed length sample temporal period. And I can't stop here, as I need not only the regression coefficients, but the residuals. Since this core dump is happening after the last executable line of function reset, and before the last executable line in my for loop in function main (and I don't have any lines of code to eb executed between the two), I wonder if this is due to an unfortunate interaction between the boost::shared_array and the gsl code. Do the gsl matrix and vector views have to be cleaned up before the memory they're configured to use is freed? Or is there something odd with boost::shared_array (I have only used boost::shared_ptr before - so I am not entirely comfortable with my knowledge of boost::shared_array)? If so, how? Or is it the case I have abused the shared_array? If so, how do I fix it? Any insights as to what may be awry would be appreciated. Cheers Ted

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[spirit, phoenix] grammars and phoenix actions
by Brian Budge 26 Mar '12

26 Mar '12

Hi all - I'm trying to transition my grammar from something like this: simple_expr = _int | '(' >> full_expr >> ')' ; sum_expr = simple_expr | (simple_expr >> '+' >> simple_expr)[_ret = _1 + _2] ; ... to something like sum_expr = simple_expr >> *(sum_expr >> '+' >> sum_expr) ; I have full grammars coded up for essentially all integer operations that could be done in C. I extended one of the simple AST examples that Joel de Guzman has written, by adding the bitwise ops and ternary operations. I'm not entirely sure why (not a grammar/parser guru), but the latter grammer is far more efficient to parse using spirit than the former. I remember writing grammars more like the first back when I used bison, but I understand the kind of parser is different (LR vs recursive descent). Anyway, on to my question. I am fine using the second type of grammar, but I've timed the parsing and evaluation of my little calculator, and AST creation and desctruction actually dwarfs parsing time. I wonder if using phoenix could speed up evaluation, and also how exactly something like the "plus" operator could be evaluated in this curried context? I've tried many searches in google, but haven't found the magic example. Thanks, Brian

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Is it possible to store a list in an interval map?
by Rajalakshmi Iyer 25 Mar '12

25 Mar '12

Hello, I have code like: int c1 = 1; set<int> s1; s1.insert(c1); // Add a number to a set interval_map< date, set<int> > cmap; // Declare an interval_map discrete_interval<date> range1 = discrete_interval<date>::closed(from_string("2012-01-01"), from_string("2012-01-30")); // Define the interval cmap += make_pair(range1, s1); // Associate the interval with the set This works well. But boost complains if I change the 'set' to a 'list' in the above code. Is only the 'set' supported as a value? Thanks! -- Twitter: @Blismobile <http://twitter.com/#!/blismobile> BlisMobile Media 32 Percy Street, London W1T 2DE www.blismobile.com [image: BlisMobile] <http://www.blismobile.com/>[image: Follow on Twitter]<http://twitter.com/#!/blismobile>[image: Blis Website] <http://www.blismobile.com/> This communication is from BlisMobile Media, which is a trading name of Breeze Tech (UK) Ltd, a company registered in England and Wales with registered number 06455773. Its registered office is 32 Percy Street, London W1T 2DE, United Kingdom. This communication contains information that is confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). If you are not the intended recipient(s), please (1) notify info(a)blismobile.com by forwarding this email and delete all copies from your system and (2) note that disclosure, distribution, copying or use of this communication is strictly prohibited. Email communications cannot be guaranteed to be secure or free from error or viruses. All emails sent to or from a Blismobile email account are securely archived and stored by an external supplier. This email does not constitute a contractual agreement; such agreements are in specified contractual or Insertion Order (IO) form only and exclusively contain all the terms to which Breeze Tech )UK) Ltd will be bound. To the extent permitted by law, Breeze Tech (UK) Ltd does not accept any liability for use of or reliance on the contents of this email by any person save by the intended recipient(s) to the extent agreed in a contract or Insertion Order. Opinions, conclusions and other information in this email which have not been delivered by way of the business of Breeze Tech (UK) Ltd are neither given nor endorsed by it.

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Re: [Boost-users] Mystery exception.
by Ted Byers 25 Mar '12

25 Mar '12

I have heard of it, but the last I checked, it didn't support Windows. I'll do a quick search and see if that has changed at all. Cheers Ted From: Sven Steckmann [mailto:sven@steckmann.de] Sent: March-25-12 4:27 PM To: boost-users(a)lists.boost.org Cc: Ted Byers Subject: Re: [Boost-users] Mystery exception. Hi Ted, I had a long look to your sources, but I am unable to find any problems there. But I think there is still one, maybe also inside the gsl if something has the wrong size. Speaking from my experience, I would not look for problems with the shared_ptr stuff. I am using it very often and as long as I had problems, these problems had their source in my program :) Do you know valgrind? In cases of memory corruption, this can be a valuable tool too. Cheers, Sven On 03/25/2012 08:00 PM, Ted Byers wrote: Hi Sven, Thanks for this. Second, in my first post, the problem was due to some unpleasant behaviour of Gnu make I wasn't aware of that resulting in a certain object file not being remade even though the source for it had changed (actually, I don't know if it is in make itself or a bug in my suite of make files - something to be investigated further - doing make realclean followed by make solved that). My current problem is something else, probably due to how memory is handled either in GSL or in boost::shared_array, but maybe something more subtle. I had left the comments in place to show alternatives I had tried. It is no surprise that compiling would fail if they were uncommented. I have now changed regressionPCA back to the way I had intended it to be in the first place. Here is the header: #ifndef REG_CLASS_H #define REG_CLASS_H #include <iosfwd> #include <vector> #include <gsl/gsl_linalg.h> #include <boost/smart_ptr/shared_array.hpp> class regressionPCA { private: unsigned int nrows, ncols; boost::shared_array<double> B, Y, U, V, S; regressionPCA(void) {}; // makes default construction impossible public: regressionPCA(const std::vector<std::vector<double> >&, const std::vector<double>&); void Reset(const std::vector<std::vector<double> >&, const std::vector<double>&); inline void setNrows(unsigned int v) { nrows = v;}; inline void setNcols(unsigned int v) { ncols = v;}; inline unsigned int getNrows(void) const { return nrows; }; inline unsigned int getNcols(void) const { return ncols; }; }; #endif And here is the implementation: #include "reg.class.h" #include <iostream> #include <algorithm> #include <gsl/gsl_linalg.h> regressionPCA::regressionPCA(const std::vector<std::vector<double> >&data, const std::vector<double>& Ydata) { Reset(data,Ydata); } void regressionPCA::Reset(const std::vector<std::vector<double> >&data, const std::vector<double>& Ydata) { unsigned int r(0),c(0),n(0); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; r = data.size(); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; c = data[0].size(); std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; setNrows(r); setNcols(c); n = r * c; std::cout << "r: " << r << "\tc: " << c << "\tn: " << n << std::endl; B.reset(new double[c]); Y.reset(new double[r]); U.reset(new double[n]); V.reset(new double[c*c]); S.reset(new double[c]); double* Btmp = B.get(); double* Ytmp = Y.get(); double* Utmp = U.get(); double* Vtmp = V.get(); double* Stmp = S.get(); double *bptr = Utmp; std::vector<std::vector<double> >::const_iterator it = data.begin(), end = data.end(); while (it != end) { bptr = std::copy(it->begin(), it->end(),bptr); ++it; } bptr = Ytmp; std::copy(Ydata.begin(),Ydata.end(),bptr); gsl_matrix_view Um = gsl_matrix_view_array(Utmp, getNrows(), getNcols()); gsl_vector_view Ym = gsl_vector_view_array(Ytmp, getNrows()); gsl_vector_view Bm = gsl_vector_view_array(Btmp, getNcols()); gsl_vector_view Sm = gsl_vector_view_array(Stmp, getNcols()); gsl_matrix_view Vm = gsl_matrix_view_array(Vtmp, getNcols(), getNcols()); gsl_linalg_SV_decomp_jacobi(&Um.matrix,&Vm.matrix,&Sm.vector); gsl_linalg_SV_solve(&Um.matrix,&Vm.matrix,&Sm.vector,&Ym.vector,&Bm.vector); std::cout << std::endl << std::endl << "Sv = " << gsl_vector_get(&Sm.vector,0) << "\t" << gsl_vector_get(&Sm.vector,1) << std::endl; std::cout << std::endl << std::endl << "V = " << std::endl; std::cout << "\t" << gsl_matrix_get(&Vm.matrix,0,0) << "\t" << gsl_matrix_get(&Vm.matrix,0,1) << std::endl; std::cout << "\t" << gsl_matrix_get(&Vm.matrix,1,0) << "\t" << gsl_matrix_get(&Vm.matrix,1,1) << std::endl; std::cout << std::endl << std::endl << "Beta = " << gsl_vector_get(&Bm.vector,0) << "\t" << gsl_vector_get(&Bm.vector,1) << std::endl; }; Obviously a work in progress as I need to create data members to store the result of the analysis, and member functions to pass the results back to the calling code. I also need to get and analyse the residuals.. Here is function main: #include <iostream> #include <vector> #include "data.generator.h" #include "reg.class.h" #include <boost/smart_ptr/shared_ptr.hpp> int main(int argc, char* argv[]) { basicGenerator bg; std::cout << "Sample size: " << bg.get_sampleSize() << std::endl; bg.makeData(); std::vector<std::vector<double> > x; std::vector<double> y; bg.getDataForRegression(x,y); unsigned int imax = y.size(); for (unsigned int i = 0 ; i < imax ; i++) { std::cout << i << "\t" << y[i] << "\t" << x[i][0] << "\t" << x[i][1] << std::endl; } std::cout << "==================================================================" << std::endl; regressionPCA rpca(x,y); std::cout << "==================================================================" << std::endl; boost::shared_ptr<regressionPCA> prpca; for (unsigned int j = 0 ; j < 25 ; j++) { std::cout << std::endl << std::endl << "Run #: " << (j + 1) << std::endl; bg.makeData(); bg.getDataForRegression(x,y); /* for (unsigned int i = 0 ; i < imax ; i++) { std::cout << i << "\t" << y[i] << "\t" << x[i][0] << "\t" << x[i][1] << std::endl; }*/ prpca.reset(new regressionPCA(x,y)); std::cout << "==================================================================" << std::endl; } return 0; } The following output shows that cleaning up the declaration and definition has not changed anything: 94 -1.86323 -1.90867 -1.35118 95 0.907604 1.14917 0.621669 96 2.1166 1.06194 1.1703 97 0.159543 0.14446 -0.665135 98 -0.508617 -0.370597 -0.703225 99 2.69086 2.75267 1.40633 ================================================================== r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Sv = 18.3225 4.69155 V = 0.695362 -0.718659 0.718659 0.695362 Beta = 0.693195 0.627794 ================================================================== Run #: 1 r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Sv = 14.1699 10.7091 V = 0.49497 -0.86891 0.86891 0.49497 Beta = 0.476181 0.391545 ================================================================== Run #: 2 r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Sv = 18.3225 4.69155 V = 0.695362 -0.718659 0.718659 0.695362 Beta = 0.693195 0.627794 Aborted (core dumped) Ted@Ted-acer-i7w7 ~/New.System/tests $ There are a couple things I see. 1) the last statement successfully executed was the last statement of my Reset function. It then returns to function main, and it's nect statement produces the line of '+' symbols, and this is not successfully executed. So, something bad is happening between the end of the function and the return to function main. 2) if I uncomment the inner loop, over I, and comment out ' prpca.reset(new regressionPCA(x,y));', that loop runs to completion. Thus, we can exclude bg from having any role in this core dump. It must be something in either gsl or boost::shared_array, or maybe boost::shared_ptr (but the core dump happens too soon to be in shared_ptr's reset, unless the output to std::cout is buffered and contents of the buffer are lost in the core dump before they can be printed, but this is unlikely). 3) It must be something subtle, as I get one execution of the analysis done in Reset, as shown in the first analysis reported by 'rpca', and then I get two complete passes through my loop over j before it crashes. I am baffled as to even how I determine whether it is something I have done wrong with GSL or with boost::shared_array. But here is an experiment I tried, let's see what you make of this. I changed my main loop to use: rpca.Reset(x,y); instead of prpca.reset(new regressionPCA(x,y)); That is, I used the object I'd made on the stack, instead of the one(s) made on the heap. I then added " std::cout << "Flag 1" << std::endl << std::flush;" right after I invoked boost::shared_array's reset, and " std::cout << "Flag 2" << std::endl << std::flush;" right after I copy new data to these arrays. Here is the result: 98 -0.508617 -0.370597 -0.703225 99 2.69086 2.75267 1.40633 ================================================================== r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Flag 1 Flag 2 Sv = 18.3225 4.69155 V = 0.695362 -0.718659 0.718659 0.695362 Beta = 0.693195 0.627794 ================================================================== Run #: 1 r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 Flag 1 Flag 2 Sv = 14.1699 10.7091 V = 0.49497 -0.86891 0.86891 0.49497 Beta = 0.476181 0.391545 ================================================================== Run #: 2 r: 0 c: 0 n: 0 r: 100 c: 0 n: 0 r: 100 c: 2 n: 0 r: 100 c: 2 n: 200 0 [main] test.pca.reg.gsl 7888 exception::handle: Error while dumping state (probably corrupted stack) Segmentation fault (core dumped) Ted@Ted-acer-i7w7 ~/New.System/tests $ Do you notice the change? Instead of finishing the second analysis in the loop, it crashes after I print the dimensions of the input matrix and vector, at some point in resetting one of the boost::shared_array objects. How do I determine whether this is a bug in boost::shared_array or some bad interaction between boost::shared_array and GSL? Cheers Ted From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Sven Steckmann Sent: March-25-12 4:13 AM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Mystery exception. Hi Ted, _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Condition Variable Notify
by Matt Fair 25 Mar '12

25 Mar '12

Hello, I'm using a condition variable to notify when I get an ack message back. For the most part it is working like it is suppose to, but I have a situation where it doesn't work. Luckly the problem is repeatable and seems to be specific to my condition variable being notified, I've included a simplified version of the code, are there any outstanding issues? I have two threads, waitForAck() is called in one and receiveAck() is called in another. class Foo { public: void waitForAck(); void receiveAck(); private: boost::mutex m_ackMutex; boost::condition_variable m_ackCond; bool m_receivedAck; }; void Foo::waitForAck() { boost::mutex::scoped_lock lock(m_ackMutex); m_receivedAck=false; //wait 8 seconds for ack boost::system_time const waitingTime=boost::get_system_time()+boost::posix_time::seconds(8); do { if(m_receivedAck) { //got ack, break out of loop break; } //Waiting for ack... } while (m_ackCond.timed_wait(lock, waitingTime)); if(!m_receivedAck) { //wait for ack timed out } } void Foo::receiveAck() { boost::mutex::scoped_lock lock(m_ackMutex); m_receivedAck = true; lock.unlock(); m_ackCond.notify_one(); } So for most of the time, this works as expected. However, at a particular part of my code waitForAck is called, then receiveAck is called in the other thread, notify is sent out but for some reason even though i'm waiting in the timed_wait in thread 1 it waits for 8 seconds and then says there was a timeout. So my questions are: 1. Does anything look off, am I using the condition variable and mutex correctly? 2. In waitForAck, I have a scope_lock that is locked, when I enter into timed_wait, does this unlock the mutex and the re-locks it when m_ackCond.notify_one() is called? 3. Are there any special circumstances with condition variable (besides receive happens before wait) where this code shouldn't behave as it should? Thanks for your help, I've been banging my head against the wall here with this! Matt

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use of boost::noncopyable ?
by John M. Dlugosz 24 Mar '12

24 Mar '12

1>V:\Trunk\stable\src\Include\Tools/unique_RAII.h(61): error C2248: 'boost::noncopyable_::noncopyable::operator =' : cannot access private member declared in class 'boost::noncopyable_::noncopyable' .... This diagnostic occurred in the compiler generated function (the normal copy constructor) That kind of defeats the purpose, doesn't it? I have to declare a dummy copy constructor to get the class to compile.

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implementing custom iterators
by MM 24 Mar '12

24 Mar '12

Hello, Can you help choosing between boost/operators.hpp(iterator_helper) and boost::iterator_facade for the implementation of a number of custom c++11-compliant iterators? What questions are to be asked? How to choose between the 2 libraries? rds, MM

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[Statechart] Does Statechart require updating?
by Dick Bridges 24 Mar '12

24 Mar '12

I used Statechart quite a bit 3-5 years ago to great advantage. Having not used it since the adoption of C++11 and seeing only a few recent related mail items, I wonder if it can still be used "as-is" or is it going to require 'adjustments' (e.g., from boost::threads to C++11 threads, etc.)? Any opinions, observations, search terms or guidelines would be greatly appreciated. In the meantime, since the projects tend to be anything but simple so I'm going to start using it as if I needn't care. Maybe I'll be able to provide some answers to my own question. 8:P Regards, Dick Bridges The opinions and data in this missive are my own and do not necessarily represent the positions, strategies, or opinions of Western Digital Corporation. [Description: Description: glenda_planet] IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses. Glenda: http://glenda.cat-v.org/gallery/

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spherical bessel functions
by David Bergman 24 Mar '12

24 Mar '12

I am using boost spherical bessel functions and get an overflow error for the following call. double ytest; double x = 12.6; int n = 8; ytest = boost::math::sph_neumann(n, x); the value of x in not relevant as long as you're away from 0. it's the index that causes the problems, for n = 8, the call to cyl_neumann(n,x) causes the overflow. I tested this with other index values less than 8 and they all work fine. I have not tried greater than 8. MATLAB is well defined for these values and I can see no reason why this case would be special. Any ideas? Thanks, David

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