spdot.c

来自「speech signal process tools」· C语言 代码 · 共 24 行

double
spdot(a,na,b,nb,n)/* dot product of double and short */
/* short is one or zero or minus one */
register double *a;
register short *b;
register int n,na,nb;
{
	register int i;
	register double dot;

	dot=0;
	for(i=0;i<n;i++,a+=na,b+=nb)
		{
		if(*b)
			{
			if(*b>0)/* *b == 1 */
				dot+=(*a);
			else/* *b == -1 */
				dot-=(*a);
			}
		}
	return(dot);
}