/*
 * xvvvtm(): z = w - x * y
 */

void dvvvtm(int n, double *w, int incw, double *x, int incx,
                   double *y, int incy, double *z, int incz)
{
  while( n-- ) {
    *z = (*w) - (*x) * (*y);
    w += incw;
    x += incx;
    y += incy;
    z += incz;
  }
  return;
}
