#include "hypre_lapack.h" #include "f2c.h" doublereal dlapy2_(doublereal *x, doublereal *y) { /* -- LAPACK auxiliary routine (version 3.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University October 31, 1992 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. ===================================================================== */ /* System generated locals */ doublereal ret_val, d__1; /* Builtin functions */ double sqrt(doublereal); /* Local variables */ static doublereal xabs, yabs, w, z__; 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_ */