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Scilab help >> API Scilab > Low level functions > Boolean sparse reading (Scilab gateway)

Boolean sparse reading (Scilab gateway)

How to read boolean sparse in a gateway.

Calling Sequence

Input argument profile:

SciErr getBooleanSparseMatrix(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int* _piNbItem, int** _piNbItemRow, int** _piColPos)

Named variable profile:

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

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 of the variable.

_piCols

Return number of columns of the variable.

_piNbItem

Return number of non zero value.

_piNbItemRow

Return number of item in each rows (size: _iRows). For "Named" function, _piNbItemRow must be allocated before calling function.

_piColPos

Return column position for each item (size: _iNbItem). For "Named" function, _piColPos must be allocated before calling function.

SciErr

Error structure where is stored errors messages history and first error number.

Description

This help describes how to read boolean sparse.

Gateway Source

int read_write_bsparse(char *fname,unsigned long fname_len)
{
    SciErr sciErr;
    int i                   = 0;
    int j                   = 0;
    int k                   = 0;

    //first variable info : real matrix of double
    int iRows               = 0;
    int iCols               = 0;
    int *piAddr             = NULL;
    int iNbItem             = 0;
    int* piNbItemRow        = NULL;
    int* piColPos           = NULL;

    int iCol                = 0;
    int iNewCol             = 0;

    int iNewItem            = 0;
    int* piNewRow           = NULL;
    int* piNewCol           = NULL;
    

    //check input and output arguments
    CheckRhs(1,1);
    CheckLhs(1,1);

    //get variable address of the first input argument
    sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddr);
    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    }

    //get size and data from Scilab memory
    sciErr = getBooleanSparseMatrix(pvApiCtx, piAddr, &iRows, &iCols, &iNbItem, &piNbItemRow, &piColPos);
    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    }

    //Do something with data
    //convert %T -> %F and %F -> %T

    iNewItem = (iRows * iCols) - iNbItem;
    piNewRow = (int*)MALLOC(sizeof(int) * iRows);
    piNewCol = (int*)MALLOC(sizeof(int) * iNewItem);

    for(i = 0 ; i < iRows ; i++)
    {
        piNewRow[i] = iCols - piNbItemRow[i];
        for(j = 0 ; j < iCols ; j++)
        {
            int iFind = 0;
            for(k = 0 ; k < piNbItemRow[i] ; k++)
            {
                if(piColPos[iCol + k] == (j + 1))
                {
                    iFind = 1;
                    break;
                }
            }
            if(iFind == 0)
            {
                piNewCol[iNewCol++] = (j + 1);
            }
        }
        iCol += piNbItemRow[i];
    }

    sciErr = createBooleanSparseMatrix(pvApiCtx, Rhs + 1, iRows, iCols, iNewItem, piNewRow, piNewCol);
    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    }

    LhsVar(1) = Rhs + 1;
    return 0;
}

Scilab test script

a = sparse([%t, %f, %t ; %f, %t, %f ; %t, %f, %t]);
a_ref = sparse([%f, %t, %f ; %t, %f, %t ; %f, %t, %f]);

b = read_write_bsparse(a);
if or(b <> a_ref) then error("failed");end
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with contributors 		Last updated:
Wed Oct 05 12:10:05 CEST 2011