Mercurial > octave-nkf
view examples/mypow2.c @ 14169:c0ca47ab7641 stable
doc: Better explain which complex result is chosen by .^
* expr.txi: Explain which complex root is chosen and how to choose a
real one if preferred.
* data.cc (power): Ditto.
* help.cc (.^, .**): Ditto. (^, **): Suggest using real-valued functions.
author | Jordi Gutiérrez Hermoso <jordigh@octave.org> |
---|---|
date | Sun, 08 Jan 2012 15:24:53 -0500 |
parents | 6cb30a539481 |
children | be41c30bcb44 |
line wrap: on
line source
#include "mex.h" void mexFunction (int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) { mwIndex i; mwSize n; double *vri, *vro; if (nrhs != 1 || ! mxIsNumeric (prhs[0])) mexErrMsgTxt ("expects matrix"); n = mxGetNumberOfElements (prhs[0]); plhs[0] = (mxArray *) mxCreateNumericArray (mxGetNumberOfDimensions (prhs[0]), mxGetDimensions (prhs[0]), mxGetClassID (prhs[0]), mxIsComplex (prhs[0])); vri = mxGetPr (prhs[0]); vro = mxGetPr (plhs[0]); if (mxIsComplex (prhs[0])) { double *vii, *vio; vii = mxGetPi (prhs[0]); vio = mxGetPi (plhs[0]); for (i = 0; i < n; i++) { vro [i] = vri [i] * vri [i] - vii [i] * vii [i]; vio [i] = 2 * vri [i] * vii [i]; } } else { for (i = 0; i < n; i++) vro [i] = vri [i] * vri [i]; } }