Daniel@0: /* CREATED:2010-01-08 17:25:37 by Brian McFee <bmcfee@cs.ucsd.edu> */
Daniel@0: /* cummax.c
Daniel@0:  *
Daniel@0:  *  cumulative maximum (analogous to cumsum)
Daniel@0:  *
Daniel@0:  * Compile: 
Daniel@0:  *  mex -DNAN_EQUALS_ZERO cummax.c
Daniel@0:  */
Daniel@0: 
Daniel@0: #include "mex.h"
Daniel@0: 
Daniel@0: 
Daniel@0: #if NAN_EQUALS_ZERO
Daniel@0: #define IsNonZero(d) ((d) != 0.0 || mxIsNan(d))
Daniel@0: #else
Daniel@0: #define IsNonZero(d) ((d) != 0.0)
Daniel@0: #endif
Daniel@0: 
Daniel@0: void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
Daniel@0: {
Daniel@0:     /* Declare variables */
Daniel@0:     int n;      /* number of elements */
Daniel@0:     double *pi; /* input array */
Daniel@0:     double *po1, *po2; /* output array(s) */
Daniel@0:     double currentMax;
Daniel@0:     double currentMaxPointer;
Daniel@0:     int i;
Daniel@0: 
Daniel@0:     if (nrhs != 1) {
Daniel@0:         mexErrMsgTxt("Only one input argument is required.");
Daniel@0:     }
Daniel@0:     if (nlhs > 2) {
Daniel@0:         mexErrMsgTxt("Too many output arguments.");
Daniel@0:     }
Daniel@0: 
Daniel@0:     if (!(mxIsDouble(prhs[0]))) {
Daniel@0:         mexErrMsgTxt("Input array must be of type double.");
Daniel@0:     }
Daniel@0: 
Daniel@0:     n       = mxGetNumberOfElements(prhs[0]);
Daniel@0:     pi      = (double *)mxGetPr(prhs[0]);
Daniel@0:     
Daniel@0:     plhs[0] = mxCreateDoubleMatrix(1, n, mxREAL);
Daniel@0:     po1     = mxGetPr(plhs[0]);
Daniel@0: 
Daniel@0:     plhs[1] = mxCreateDoubleMatrix(1, n, mxREAL);
Daniel@0:     po2     = mxGetPr(plhs[1]);
Daniel@0: 
Daniel@0:     /* Now for the meat */
Daniel@0: 
Daniel@0:     currentMax = pi[0];
Daniel@0:     currentMaxPointer = 1;
Daniel@0:     for (i = 0; i < n; i++) {
Daniel@0:         if (pi[i] > currentMax) {
Daniel@0:             currentMax          = pi[i];
Daniel@0:             currentMaxPointer   = i + 1;
Daniel@0:         }
Daniel@0:         po1[i] = currentMax;
Daniel@0:         po2[i] = currentMaxPointer;
Daniel@0:     }
Daniel@0: 
Daniel@0:     mxSetN(plhs[0], n);
Daniel@0:     mxSetN(plhs[1], n);
Daniel@0: 
Daniel@0: }