Double management

How to manage Scilab’s variable read and write process using call_scilab and api_scilab

Description

This help describes how doubles and matrix of doubles can be handle through the `Call Scilab API`_ and api Scilab.

There are several functions which can be used to read / write from the memory of Scilab. These functions are described in dedicated pages.

Note that the default type of a numeric value in Scilab is double. For example, in a=1 or a=[1,2], a will be consider as a double.

Note: Access to variables is done through api Scilab (named variable).

Examples

/*
 * Write a `matrix`_ into Scilab
 * B=[1 4 2 3;
 *    3 9 8 2 ]
 * Note that it is done column by column
 */
`double`_ B[] = {1,3,4,9,2,8,3,2};   /* Declare the `matrix`_ */
`int`_ rowB = 2, colB = 4; /* Size of the `matrix`_ */
`char`_ variableNameB[] = "B";
SciErr sciErr;

/*
 * Write it into Scilab's memory
 */
sciErr = createNamedMatrixOfDouble(pvApiCtx,variableNameB,rowB,colB, B); /* pvApiCtx is a `global`_ variable */
if(sciErr.iErr)
{
    printError(&sciErr, 0);
}

/*
 * Prior to Scilab 5.2:
 * C2F(cwritemat)(variableNameB, &rowB, &colB, B, strlen(variableNameB));
*/

printf("\n");
printf("Display from Scilab of B:\n");
SendScilabJob("disp(B);"); /* Display B */

/* Read the previously declared `matrix`_ of double B */
`int`_ rowB_ = 0, colB_ = 0, lp_ = 0;
`double`_ *matrixOfDoubleB = NULL;
`int`_ i = 0, j = 0;
`char`_ variableToBeRetrievedB[] = "B";
SciErr sciErr;

/* First, retrieve the `size`_ of the matrix */
sciErr = readNamedMatrixOfDouble(pvApiCtx, variableToBeRetrievedB, &rowB_, &colB_, NULL);
if(sciErr.iErr)
{
    printError(&sciErr, 0);
}

/*
 * Prior to Scilab 5.2:
 * C2F(cmatptr)(variableToBeRetrievedB, &rowB_, &colB_, &lp_, strlen(variableToBeRetrievedB));
 */

/* Alloc the memory */
matrixOfDoubleB = (`double`_*)malloc((rowB_*colB_)*sizeof(`double`_));

/* Load the `matrix`_ */
sciErr = readNamedMatrixOfDouble(pvApiCtx, variableToBeRetrievedB, &rowB_, &colB_, matrixOfDoubleB);
if(sciErr.iErr)
{
    printError(&sciErr, 0);
}

/*
 * Prior to Scilab 5.2:
 * C2F(creadmat)(variableToBeRetrievedB,&rowB_,&colB_,matrixOfDoubleB,strlen(variableToBeRetrievedB) );
 */

printf("\n");
printf("Display from B formated (size: %d, %d):\n",rowB_, colB_);
for(j = 0 ; j < rowB_ ; j++)
 {
  for(i = 0 ; i < colB_ ; i++)
   {
    /* Display the formated `matrix`_ ... the way the user
     * expect */
    printf("%5.2f ",matrixOfDoubleB[i * rowB_ + j]);
   }
  printf("\n"); /* New row of the `matrix`_ */
 }

See Also

• `Call_Scilab`_ call_scilab is an interface which provides the ability to call Scilab engine from C/C++ code
• api Scilab api_scilab is the Scilab interface to read/write data from/to Scilab memory
• `API_Scilab: Double reading`_ How to read matrices of double in a gateway.
• `API_Scilab: Double writing`_ How to write matrices of doubles in a gateway.
• SendScilabJob Send a Scilab task from a C/C++ code (call_scilab)
• StartScilab Initializes and starts Scilab engine in Call Scilab
• `Call_Scilab: BooleanManagement`_ How to manage Scilab’s boolean read and write process using call_scilab and api_scilab
• `Call_Scilab: ComplexManagement`_ How to manage Scilab’s complex variable read and write process using call_scilab
• `Call_Scilab: StringManagement`_ How to manage Scilab’s String read and write process using call_scilab and api_scilab
• `API_Scilab: Boolean Reading`_ How to read matrix of boolean.
• `API_Scilab: Boolean Writing`_ How to write matrices of boolean.
• `API_Scilab: String Reading`_ How to read matrices of strings in a gateway.
• `API_Scilab: String Writing`_ How to write matrices of string in a gateway.