dscal.c

SuperLU is a general purpose library for the direct solution of large, sparse, nonsymmetric systems

/*  -- translated by f2c (version 19940927).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* Subroutine */ int dscal_(integer *n, doublereal *da, doublereal *dx, 
	integer *incx)
{


    /* System generated locals */
    integer i__1, i__2;

    /* Local variables */
    static integer i, m, nincx, mp1;


/*     scales a vector by a constant.   
       uses unrolled loops for increment equal to one.   
       jack dongarra, linpack, 3/11/78.   
       modified 3/93 to return if incx .le. 0.   
       modified 12/3/93, array(1) declarations changed to array(*)   


    
   Parameter adjustments   
       Function Body */
#define DX(I) dx[(I)-1]


    if (*n <= 0 || *incx <= 0) {
	return 0;
    }
    if (*incx == 1) {
	goto L20;
    }

/*        code for increment not equal to 1 */

    nincx = *n * *incx;
    i__1 = nincx;
    i__2 = *incx;
    for (i = 1; *incx < 0 ? i >= nincx : i <= nincx; i += *incx) {
	DX(i) = *da * DX(i);
/* L10: */
    }
    return 0;

/*        code for increment equal to 1   


          clean-up loop */

L20:
    m = *n % 5;
    if (m == 0) {
	goto L40;
    }
    i__2 = m;
    for (i = 1; i <= m; ++i) {
	DX(i) = *da * DX(i);
/* L30: */
    }
    if (*n < 5) {
	return 0;
    }
L40:
    mp1 = m + 1;
    i__2 = *n;
    for (i = mp1; i <= *n; i += 5) {
	DX(i) = *da * DX(i);
	DX(i + 1) = *da * DX(i + 1);
	DX(i + 2) = *da * DX(i + 2);
	DX(i + 3) = *da * DX(i + 3);
	DX(i + 4) = *da * DX(i + 4);
/* L50: */
    }
    return 0;
} /* dscal_ */