129 lines
3.9 KiB
C++
129 lines
3.9 KiB
C++
/* fortran/dlabad.f -- translated by f2c (version 20200916).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "lmp_f2c.h"
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/* > \brief \b DLABAD */
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/* =========== DOCUMENTATION =========== */
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/* Online html documentation available at */
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/* http://www.netlib.org/lapack/explore-html/ */
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/* > \htmlonly */
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/* > Download DLABAD + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlabad.
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f"> */
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/* > [TGZ]</a> */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlabad.
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f"> */
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/* > [ZIP]</a> */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlabad.
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f"> */
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/* > [TXT]</a> */
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/* > \endhtmlonly */
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/* Definition: */
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/* =========== */
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/* SUBROUTINE DLABAD( SMALL, LARGE ) */
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/* .. Scalar Arguments .. */
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/* DOUBLE PRECISION LARGE, SMALL */
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/* .. */
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/* > \par Purpose: */
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/* ============= */
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/* > */
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/* > \verbatim */
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/* > */
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/* > DLABAD takes as input the values computed by DLAMCH for underflow and */
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/* > overflow, and returns the square root of each of these values if the */
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/* > log of LARGE is sufficiently large. This subroutine is intended to */
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/* > identify machines with a large exponent range, such as the Crays, and */
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/* > redefine the underflow and overflow limits to be the square roots of */
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/* > the values computed by DLAMCH. This subroutine is needed because */
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/* > DLAMCH does not compensate for poor arithmetic in the upper half of */
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/* > the exponent range, as is found on a Cray. */
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/* > \endverbatim */
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/* Arguments: */
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/* ========== */
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/* > \param[in,out] SMALL */
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/* > \verbatim */
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/* > SMALL is DOUBLE PRECISION */
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/* > On entry, the underflow threshold as computed by DLAMCH. */
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/* > On exit, if LOG10(LARGE) is sufficiently large, the square */
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/* > root of SMALL, otherwise unchanged. */
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/* > \endverbatim */
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/* > */
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/* > \param[in,out] LARGE */
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/* > \verbatim */
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/* > LARGE is DOUBLE PRECISION */
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/* > On entry, the overflow threshold as computed by DLAMCH. */
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/* > On exit, if LOG10(LARGE) is sufficiently large, the square */
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/* > root of LARGE, otherwise unchanged. */
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/* > \endverbatim */
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/* Authors: */
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/* ======== */
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/* > \author Univ. of Tennessee */
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/* > \author Univ. of California Berkeley */
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/* > \author Univ. of Colorado Denver */
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/* > \author NAG Ltd. */
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/* > \ingroup OTHERauxiliary */
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/* ===================================================================== */
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/* Subroutine */ int dlabad_(doublereal *small, doublereal *large)
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{
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/* Builtin functions */
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double d_lg10(doublereal *), sqrt(doublereal);
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/* -- LAPACK auxiliary routine -- */
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/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
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/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
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/* .. Scalar Arguments .. */
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/* .. */
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/* ===================================================================== */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* If it looks like we're on a Cray, take the square root of */
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/* SMALL and LARGE to avoid overflow and underflow problems. */
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if (d_lg10(large) > 2e3) {
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*small = sqrt(*small);
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*large = sqrt(*large);
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}
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return 0;
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/* End of DLABAD */
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} /* dlabad_ */
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#ifdef __cplusplus
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}
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#endif
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