--- /dev/null
+#include "clapack.h"
+
+doublereal dasum_(integer *n, doublereal *dx, integer *incx)
+{
+ /* System generated locals */
+ integer i__1, i__2;
+ doublereal ret_val, d__1, d__2, d__3, d__4, d__5, d__6;
+
+ /* Local variables */
+ integer i__, m, mp1;
+ doublereal dtemp;
+ integer nincx;
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* takes the sum of the absolute values. */
+/* 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(*) */
+
+
+/* .. Local Scalars .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+ /* Parameter adjustments */
+ --dx;
+
+ /* Function Body */
+ ret_val = 0.;
+ dtemp = 0.;
+ if (*n <= 0 || *incx <= 0) {
+ return ret_val;
+ }
+ if (*incx == 1) {
+ goto L20;
+ }
+
+/* code for increment not equal to 1 */
+
+ nincx = *n * *incx;
+ i__1 = nincx;
+ i__2 = *incx;
+ for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
+ dtemp += (d__1 = dx[i__], abs(d__1));
+/* L10: */
+ }
+ ret_val = dtemp;
+ return ret_val;
+
+/* code for increment equal to 1 */
+
+
+/* clean-up loop */
+
+L20:
+ m = *n % 6;
+ if (m == 0) {
+ goto L40;
+ }
+ i__2 = m;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+ dtemp += (d__1 = dx[i__], abs(d__1));
+/* L30: */
+ }
+ if (*n < 6) {
+ goto L60;
+ }
+L40:
+ mp1 = m + 1;
+ i__2 = *n;
+ for (i__ = mp1; i__ <= i__2; i__ += 6) {
+ dtemp = dtemp + (d__1 = dx[i__], abs(d__1)) + (d__2 = dx[i__ + 1],
+ abs(d__2)) + (d__3 = dx[i__ + 2], abs(d__3)) + (d__4 = dx[i__
+ + 3], abs(d__4)) + (d__5 = dx[i__ + 4], abs(d__5)) + (d__6 =
+ dx[i__ + 5], abs(d__6));
+/* L50: */
+ }
+L60:
+ ret_val = dtemp;
+ return ret_val;
+} /* dasum_ */