User`s guide

3 Writing S-Functions As C-MEX files
3-92
if (den0 == 0.0) {
den0 = mxGetPr(DEN(S))[0];
}
/*
* Grab the numerator.
*/
allZero = 1;
for (i = 0; (i < nCoeffs) && allZero; i++) {
allZero &= *uPtrs[uIdx+i] == 0.0;
}
if (allZero) { /* if numerator is all zero */
const real_T *numParam = mxGetPr(NUM(S));
int_T numParamLen = mxGetNumberOfElements(NUM(S));
/*
* Move the input to the denominator input and
* get the denominator from the input parameter.
*/
uIdx += nCoeffs;
num += nCoeffs - numParamLen;
for (i = 0; i < numParamLen; i++) {
*num++ = *numParam++ / den0;
}
} else {
for (i = 0; i < nCoeffs; i++) {
*num++ = *uPtrs[uIdx++] / den0;
}
}
/*
* Grab the denominator.
*/
allZero = 1;
for (i = 0; (i < nCoeffs) && allZero; i++) {
allZero &= *uPtrs[uIdx+i] == 0.0;
}
if (allZero) { /* If denominator is all zero. */
const real_T *denParam = mxGetPr(DEN(S));
int_T denParamLen = mxGetNumberOfElements(DEN(S));
den0 = denParam[0];
for (i = 0; i < denParamLen; i++) {
*den++ = *denParam++ / den0;
}
} else {
for (i = 0; i < nCoeffs; i++) {
*den++ = *uPtrs[uIdx++] / den0;
}
}
/*