Sparse matrix reading (Scilab gateway)

How to read sparse matrices in a gateway.

Calling Sequence

Input argument profile:

SciErr getSparseMatrix(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int* _piNbItem, int** _piNbItemRow, int** _piColPos, double** _pdblReal)

SciErr getComplexSparseMatrix(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int* _piNbItem, int** _piNbItemRow, int** _piColPos, double** _pdblReal, double** _pdblImg)

Named variable profile:

SciErr readNamedSparseMatrix(void* _pvCtx, const char* _pstName, int* _piRows, int* _piCols, int* _piNbItem, int* _piNbItemRow, int* _piColPos, double* _pdblReal)

SciErr readNamedComplexSparseMatrix(void* _pvCtx, const char* _pstName, int* _piRows, int* _piCols, int* _piNbItem, int* _piNbItemRow, int* _piColPos, double* _pdblReal, double* _pdblImg)

Arguments

:_pvCtx Scilab environment pointer, pass in “pvApiCtx” provided by

api_scilab.h.

: :_piAddress Address of the Scilab variable. : :_pstName Name of the variable for “named” functions. : :_piRows Return number of rows. : :_piCols Return number of columns. : :_piNbItem Return number of non zero value. : :_piNbItemRow Return number of item in each rows (size: _iRows). : :_piColPos Return column position for each item (size: _iNbItem). : :_pdblReal Return address of real data array (size: _iCols * _iRows)

For “Named” function, _pdblReal must be allocated before calling function.

: :_pdblImg Return address of imaginary data array (size: _iCols *

_iRows) For “Named” function, _pdblImg must be allocated before calling function.

: :SciErr Error structure where is stored errors messages history and

first error number.

:

Description

This help describes how sparse matrix can be handled through the Scilab API.

Gateway Source

#include "api_scilab.h"
int read_sparse(char *fname,unsigned long fname_len)
{
    SciErr sciErr;
    int i,j,k;
    int* piAddr                     = NULL;
    int iRows                       = 0;
    int iCols                       = 0;
    int iNbItem                     = 0;
    int* piNbItemRow        = NULL;
    int* piColPos           = NULL;
    double* pdblReal        = NULL;
    double* pdblImg         = NULL;

    CheckInputArgument(pvApiCtx, 1, 1);

    sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddr);
    if(sciErr.iErr)
    {
            printError(&sciErr, 0);
            return 0;
    }

    if(isVarComplex(pvApiCtx, piAddr))
    {
            sciErr = getComplexSparseMatrix(pvApiCtx, piAddr, &iRows, &iCols, &iNbItem, &piNbItemRow, &piColPos, &pdblReal, &pdblImg);
    }
    else
    {
            sciErr = getSparseMatrix(pvApiCtx, piAddr, &iRows, &iCols, &iNbItem, &piNbItemRow, &piColPos, &pdblReal);
    }

    if(sciErr.iErr)
    {
            printError(&sciErr, 0);
            return 0;
    }

    sciprint("Sparse %d item(s)\n", iNbItem);
    k = 0;

    for(i = 0 ; i < iRows ; i++)
    {
            for(j = 0 ; j < piNbItemRow[i] ; j++)
            {
                    sciprint("(%d,%d) = %f", i+1, piColPos[k], pdblReal[k]);
                    if(isVarComplex(pvApiCtx, piAddr))
                    {
                            sciprint(" %+fi", pdblImg[k]);
                    }

                    sciprint("\n");
                    k++;
            }
    }

    //assign allocated variables to Lhs position
    AssignOutputVariable(1) = 0;
    return 0;
}

Scilab test script

sp=`sparse`_([1,2;4,5;3,10],[1 + 2*%i,2 - 3*%i,-3 + 4*%i]);
read_sparse(sp);