Name

Double reading (Scilab gateway) — How to read matrices of double in a gateway.

Calling Sequence

Input argument profile:

SciErr getMatrixOfDouble(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, double** _pdblReal)
SciErr getComplexMatrixOfDouble(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, double** _pdblReal, double** _pdblImg)

Named variable profile:

SciErr readNamedMatrixOfDouble(void* _pvCtx, char* _pstName, int* _piRows, int* _piCols, double* _pdblReal)
SciErr readNamedComplexMatrixOfDouble(void* _pvCtx, char* _pstName, int* _piRows, int* _piCols, double* _pdblReal, double* _pdblImg)

Parameters

_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.

_pdblReal

Return address of real data array (size: _iCols * _iRows).

_pdblImg

Return address of imaginary data array (size: _iCols * _iRows).

This argument does not exist with getMatrixOfDouble and readNamedMatrixOfDouble.

SciErr

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

Description

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

Gateway Source

	 
int read_double(char *fname,unsigned long fname_len)
{
	int i;
	//first variable info : real matrix of double
	int iType			= 0;
	int iRows			= 0;
	int iCols			= 0;
	int iComplex		= 0;
	int *piAddr			= NULL;
	double* pdblReal	= NULL;
	double* pdblImg		= NULL;

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


	/************************
	*    First variable    *
	************************/

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

	//check type
	sciErr = getVarType(pvApiCtx, piAddr, &iType);
	if(sciErr.iErr || iType != sci_matrix)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//get complexity
	iComplex	= isVarComplex(pvApiCtx, piAddr);

	//check complexity
	if(iComplex)
	{
		//get size and data from Scilab memory
		sciErr = getComplexMatrixOfDouble(pvApiCtx, piAddr, &iRows, &iCols, &pdblReal, &pdblImg);
	}
	else
	{
		//get size and data from Scilab memory
		sciErr = getMatrixOfDouble(pvApiCtx, piAddr, &iRows, &iCols, &pdblReal);
	}

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

	//Do something with data
	//if variable is complex, switch real part and imaginary part otherwise multiply by -1

	if(iComplex)
	{
		sciErr = createComplexMatrixOfDouble(pvApiCtx, Rhs + 1, iRows, iCols, pdblImg, pdblReal);
	}
	else
	{
		for(i = 0 ; i < iRows * iCols ; i++)
		{
			pdblReal[i] = pdblReal[i] * -1;
		}
		sciErr = createMatrixOfDouble(pvApiCtx, Rhs + 1, iRows, iCols, pdblReal);
	}

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

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

Scilab test script

 
a = [   0 1 2 3; ..
        4 5 6 7; ..
        8 9 10 11];
b = [   23*%i,      1+22*%i,    2+21*%i,    3+20*%i,    4+19*%i,    5+18*%i; ..
        6+17*%i,    7+16*%i,    8+15*%i,    9+14*%i,     10+13*%i,  11+12*%i; ..
        12+11*%i,   13+10*%i,   14+9*%i,    15+8*%i,    16+7*%i,    17+6*%i; ..
        18+5*%i,    19+4*%i,    20+3*%i,    21+2*%i,    22+1*%i,    23];

a2 = read_double(a);
b2 = read_double(b);

if or(a2 <> a * -1) then error("failed"), end
if or(b2 <> (imag(b) + real(b) * %i)) then error("failed"), end