biterrfast.c

来自「空时编码源代码」· C语言 代码 · 共 61 行

/* Bit or symbol error rate calculator. 
 * July 08, 2003
 * B. Nugroho */

#include "mex.h"

void bit_err(double num[], double rat[], double a[], double b[], int L)
{
    int err = 0;
    int i;
    
    for(i=0; i<L; i++)
    {
        if(a[i] != b[i])
            err++;
    }
    /* Return the total number of errors. */    
    num[0] = err;
    
    /* Return the error ratio. */
    rat[0] = err/L;
}
              
void mexFunction( int nlhs, mxArray *plhs[],
                  int nrhs, const mxArray *prhs[])
{
    double *a,*b;    
    int K, L1, L2;
    double *num, *rat;
    
    /* Get the input vector length */
    K = mxGetM(prhs[0]);
    L1 = mxGetN(prhs[0]);
    L2 = mxGetN(prhs[1]);
    
    /* Check whether both vectors have the same length */
    if( L1 != L2) {
       mexErrMsgTxt("Vector length must be the same");
    }
    
    /* Check vector dimension */
    if( K > 1) {
       mexErrMsgTxt("Dimension must be (1,length)");
    }
    
    /* Create 1x1 matrix for return arguments */
    plhs[0] = mxCreateDoubleMatrix(1,1,mxREAL);
    plhs[1] = mxCreateDoubleMatrix(1,1,mxREAL);
    
    /* Get the vectors value of the inputs a and b. */   
    a = mxGetPr(prhs[0]);
    b = mxGetPr(prhs[1]);
   
    /* Assign pointer to the output. */
    num = mxGetPr(plhs[0]);
    rat = mxGetPr(plhs[1]);
   
    /* Call the subroutine */
    bit_err(num,rat,a,b,L1);
}