[Boost-users] Mystery exception.

25 Mar 2012

      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

[Boost-users] Mystery exception.

Ted Byers