matfileTutorial.cc

Introduction

This Tutorials shows the general use of matfiles in Concepts. A tool that allows yourself to store concepts::DenseMatrix<T> and concepts::SparseMatrix<T> in a binary format, which can be read with Matlab/Octave or MatfileInput to regain matrices in Concepts.

Contents

1. Commented Program
   1. Preparations
   2. MatfileOutput
   3. MatfileInput
   4. Output
2. Complete Source Code

Commented Program

Include files for input/output handling and matrices.

#include "matfile.hh"
#include "operator.hh"

Preparations

In the first lines some matrices for later handling are initialisized.

    uint ddimX = 3;
    uint ddimY = 3;
    uint sdimX = 4;
    uint sdimY = 5;
  
    concepts::DenseMatrix<Cmplx> dCmplx(ddimX,ddimY);
    concepts::SparseMatrix<Real> sReal(sdimX,sdimY);
  
    for(uint i=0; i<ddimX; ++i){
      for(uint j=0; j<ddimY; ++j){
        dCmplx(i,j) = std::complex<double>(1,1);
      }
    }
  
    for(uint i=0;i<sdimX;++i)
      sReal(i,i)=i;

MatfileOutput

First one has to create a concepts::MatfileOutput with a string as input, that will be the name of the matfile. The methods addDense and addSparse expect a reference of a matrix and a string, which will be the name of the matrix in the matfile.

    concepts::MatfileOutput mo("File");
    mo.addDense(&dCmplx,"dense_cmplx");
    mo.addSparse(&sReal, "sparse_real");
    mo.closeMatfile();

MatfileInput

In order to regain matrices one has to create a concepts::MatfileInput with a string as input, that is the name of the matfile. The methods getDense<T> and getSparse<T> expect a type T, that is either real or complex. As input the name of the matrix in the matfile is needed. Methods return pointers to the matrices.

    concepts::MatfileInput mi("File");
    concepts::DenseMatrix<Cmplx>* 
      dCmplx_correct_ptr = mi.getDense<Cmplx>("dense_cmplx");
    concepts::SparseMatrix<Real>* 
      sReal_ptr          = mi.getSparse<Real>("sparse_real");

Be sure to know the field over which the matrices are defined. Else some data will be lost (compare to Output ).

    concepts::DenseMatrix<Real>* 
      dcmplx_wrong_ptr = mi.getDense<Real>("dense_cmplx");

Output

Output of the main. Notice the lost data in the second matrix.

$ ./matfileTutorial
DenseMatrix (correct) Output:
DenseMatrix(3x3, [
1.000000e+00+i  1.000000e+00+i  1.000000e+00+i
1.000000e+00+i  1.000000e+00+i  1.000000e+00+i
1.000000e+00+i  1.000000e+00+i  1.000000e+00+i])
DenseMatrix (wrong) Output:
DenseMatrix(3x3, [
1.000000e+00  1.000000e+00  1.000000e+00
1.000000e+00  1.000000e+00  1.000000e+00
1.000000e+00  1.000000e+00  1.000000e+00])
SparseMatrix Output:
1.000000e+00,   2.000000e+00,   3.000000e+00,   

Complete Source Code

Author:

Christian Heier, Robert Gruhlke, 2011

#include "basics/exceptions.hh"
#include "matfile.hh"
#include "operator.hh"


using concepts::Real;
using concepts::Cmplx;

int main(int argc, char** argv) {

  concepts::Stacktrace::doit() = false;

  try {
    
    // ** preparations **
    uint ddimX = 3;
    uint ddimY = 3;
    uint sdimX = 4;
    uint sdimY = 5;
  
    concepts::DenseMatrix<Cmplx> dCmplx(ddimX,ddimY);
    concepts::SparseMatrix<Real> sReal(sdimX,sdimY);
  
    for(uint i=0; i<ddimX; ++i){
      for(uint j=0; j<ddimY; ++j){
        dCmplx(i,j) = std::complex<double>(1,1);
      }
    }
  
    for(uint i=0;i<sdimX;++i)
      sReal(i,i)=i;
    
    // ** write matrices to matfile **
    concepts::MatfileOutput mo("File");
    mo.addDense(&dCmplx,"dense_cmplx");
    mo.addSparse(&sReal, "sparse_real");
    mo.closeMatfile();
    
    // ** read matrices from matfile **
    concepts::MatfileInput mi("File");
    concepts::DenseMatrix<Cmplx>* 
      dCmplx_correct_ptr = mi.getDense<Cmplx>("dense_cmplx");
    concepts::SparseMatrix<Real>* 
      sReal_ptr          = mi.getSparse<Real>("sparse_real");
    
    // ** read matrices from matfile incorrectly **
    concepts::DenseMatrix<Real>* 
      dcmplx_wrong_ptr = mi.getDense<Real>("dense_cmplx");
    
    // ** output of program **
    std::cout << "DenseMatrix (correct) Output:" << std::endl;
    std::cout << *dCmplx_correct_ptr << std::endl;  
    std::cout << "DenseMatrix (wrong) Output:" << std::endl;
    std::cout << *dcmplx_wrong_ptr << std::endl;  
   
    std::cout << "SparseMatrix Output:" << std::endl;
    for(concepts::SparseMatrix<Real>::const_iterator iter=sReal_ptr->begin();iter!=sReal_ptr->end();++iter)
      std::cout << *iter << ",   ";
    std::cout << std::endl;

  }
  catch(concepts::ExceptionBase& e) {
    std::cout << e << std::endl;
    return 1;
  }
}