--- /dev/null
+#include "clapack.h"
+
+doublereal dlapy2_(doublereal *x, doublereal *y)
+{
+ /* System generated locals */
+ doublereal ret_val, d__1;
+
+ /* Builtin functions */
+ double sqrt(doublereal);
+
+ /* Local variables */
+ doublereal w, z__, xabs, yabs;
+
+
+/* -- LAPACK auxiliary routine (version 3.1) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary */
+/* overflow. */
+
+/* Arguments */
+/* ========= */
+
+/* X (input) DOUBLE PRECISION */
+/* Y (input) DOUBLE PRECISION */
+/* X and Y specify the values x and y. */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+ xabs = abs(*x);
+ yabs = abs(*y);
+ w = max(xabs,yabs);
+ z__ = min(xabs,yabs);
+ if (z__ == 0.) {
+ ret_val = w;
+ } else {
+/* Computing 2nd power */
+ d__1 = z__ / w;
+ ret_val = w * sqrt(d__1 * d__1 + 1.);
+ }
+ return ret_val;
+
+/* End of DLAPY2 */
+
+} /* dlapy2_ */