00001 /* dlapy2.f -- translated by f2c (version 20061008). 00002 You must link the resulting object file with libf2c: 00003 on Microsoft Windows system, link with libf2c.lib; 00004 on Linux or Unix systems, link with .../path/to/libf2c.a -lm 00005 or, if you install libf2c.a in a standard place, with -lf2c -lm 00006 -- in that order, at the end of the command line, as in 00007 cc *.o -lf2c -lm 00008 Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., 00009 00010 http://www.netlib.org/f2c/libf2c.zip 00011 */ 00012 00013 #include "f2c.h" 00014 #include "blaswrap.h" 00015 00016 doublereal dlapy2_(doublereal *x, doublereal *y) 00017 { 00018 /* System generated locals */ 00019 doublereal ret_val, d__1; 00020 00021 /* Builtin functions */ 00022 double sqrt(doublereal); 00023 00024 /* Local variables */ 00025 doublereal w, z__, xabs, yabs; 00026 00027 00028 /* -- LAPACK auxiliary routine (version 3.2) -- */ 00029 /* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ 00030 /* November 2006 */ 00031 00032 /* .. Scalar Arguments .. */ 00033 /* .. */ 00034 00035 /* Purpose */ 00036 /* ======= */ 00037 00038 /* DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary */ 00039 /* overflow. */ 00040 00041 /* Arguments */ 00042 /* ========= */ 00043 00044 /* X (input) DOUBLE PRECISION */ 00045 /* Y (input) DOUBLE PRECISION */ 00046 /* X and Y specify the values x and y. */ 00047 00048 /* ===================================================================== */ 00049 00050 /* .. Parameters .. */ 00051 /* .. */ 00052 /* .. Local Scalars .. */ 00053 /* .. */ 00054 /* .. Intrinsic Functions .. */ 00055 /* .. */ 00056 /* .. Executable Statements .. */ 00057 00058 xabs = abs(*x); 00059 yabs = abs(*y); 00060 w = max(xabs,yabs); 00061 z__ = min(xabs,yabs); 00062 if (z__ == 0.) { 00063 ret_val = w; 00064 } else { 00065 /* Computing 2nd power */ 00066 d__1 = z__ / w; 00067 ret_val = w * sqrt(d__1 * d__1 + 1.); 00068 } 00069 return ret_val; 00070 00071 /* End of DLAPY2 */ 00072 00073 } /* dlapy2_ */