Abdelrahman Said
119 lines
3.6 KiB
C
119 lines
3.6 KiB
C
/* -- translated by f2c (version 20240504).
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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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#include "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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DOUBLE PRECISION LARGE, SMALL
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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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> \date November 2011
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> \ingroup auxOTHERauxiliary
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=====================================================================
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Subroutine */ int igraphdlabad_(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 (version 3.4.0) --
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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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November 2011
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=====================================================================
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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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} /* igraphdlabad_ */
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