/* fortran/dlapy3.f -- translated by f2c (version 20200916). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib; on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */ #ifdef __cplusplus extern "C" { #endif #include "lmp_f2c.h" /* > \brief \b DLAPY3 returns sqrt(x2+y2+z2). */ /* =========== DOCUMENTATION =========== */ /* Online html documentation available at */ /* http://www.netlib.org/lapack/explore-html/ */ /* > \htmlonly */ /* > Download DLAPY3 + dependencies */ /* > */ /* > [TGZ] */ /* > */ /* > [ZIP] */ /* > */ /* > [TXT] */ /* > \endhtmlonly */ /* Definition: */ /* =========== */ /* DOUBLE PRECISION FUNCTION DLAPY3( X, Y, Z ) */ /* .. Scalar Arguments .. */ /* DOUBLE PRECISION X, Y, Z */ /* .. */ /* > \par Purpose: */ /* ============= */ /* > */ /* > \verbatim */ /* > */ /* > DLAPY3 returns sqrt(x**2+y**2+z**2), taking care not to cause */ /* > unnecessary overflow and unnecessary underflow. */ /* > \endverbatim */ /* Arguments: */ /* ========== */ /* > \param[in] X */ /* > \verbatim */ /* > X is DOUBLE PRECISION */ /* > \endverbatim */ /* > */ /* > \param[in] Y */ /* > \verbatim */ /* > Y is DOUBLE PRECISION */ /* > \endverbatim */ /* > */ /* > \param[in] Z */ /* > \verbatim */ /* > Z is DOUBLE PRECISION */ /* > X, Y and Z specify the values x, y and z. */ /* > \endverbatim */ /* Authors: */ /* ======== */ /* > \author Univ. of Tennessee */ /* > \author Univ. of California Berkeley */ /* > \author Univ. of Colorado Denver */ /* > \author NAG Ltd. */ /* > \ingroup OTHERauxiliary */ /* ===================================================================== */ doublereal dlapy3_(doublereal *x, doublereal *y, doublereal *z__) { /* System generated locals */ doublereal ret_val, d__1, d__2, d__3; /* Builtin functions */ double sqrt(doublereal); /* Local variables */ doublereal w, xabs, yabs, zabs; extern doublereal dlamch_(char *, ftnlen); doublereal hugeval; /* -- LAPACK auxiliary routine -- */ /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */ /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */ /* .. Scalar Arguments .. */ /* .. */ /* ===================================================================== */ /* .. Parameters .. */ /* .. */ /* .. Local Scalars .. */ /* .. */ /* .. External Subroutines .. */ /* .. */ /* .. Intrinsic Functions .. */ /* .. */ /* .. Executable Statements .. */ hugeval = dlamch_((char *)"Overflow", (ftnlen)8); xabs = abs(*x); yabs = abs(*y); zabs = abs(*z__); /* Computing MAX */ d__1 = max(xabs,yabs); w = max(d__1,zabs); if (w == 0. || w > hugeval) { /* W can be zero for max(0,nan,0) */ /* adding all three entries together will make sure */ /* NaN will not disappear. */ ret_val = xabs + yabs + zabs; } else { /* Computing 2nd power */ d__1 = xabs / w; /* Computing 2nd power */ d__2 = yabs / w; /* Computing 2nd power */ d__3 = zabs / w; ret_val = w * sqrt(d__1 * d__1 + d__2 * d__2 + d__3 * d__3); } return ret_val; /* End of DLAPY3 */ } /* dlapy3_ */ #ifdef __cplusplus } #endif