snrm2r.c

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/* Euclidean norm of the n-vector stored in sx()
   with storage -- row vector version
   Ver.1.0, July,1,1988.                         */
 
#include "arith.h"
 
REAL snrm2r(n,sx,isx,jsx,incx)
int n,isx,jsx,incx;
MATRIX sx;
{
    int i;
    REAL sum,enorm;
 
    if(n <=0)
        return(0.0);
 
    sum=0.0e0;
 
    for(i=0; i<n; i += incx){
        sum += sx[isx][jsx+i]*sx[isx][jsx+i];
    }
 
    enorm= sqrt(fabs(sum));
 
    if(enorm < EPS)
        enorm= 0.0e0;
 
    return(enorm);
}