/* -- translated by f2c (version 20100827). 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 */ #include "f2c.h" /* > \brief \b DLABAD =========== DOCUMENTATION =========== Online html documentation available at http://www.netlib.org/lapack/explore-html/ > \htmlonly > Download DLABAD + dependencies > > [TGZ] > > [ZIP] > > [TXT] > \endhtmlonly Definition: =========== SUBROUTINE DLABAD( SMALL, LARGE ) DOUBLE PRECISION LARGE, SMALL > \par Purpose: ============= > > \verbatim > > DLABAD takes as input the values computed by DLAMCH for underflow and > overflow, and returns the square root of each of these values if the > log of LARGE is sufficiently large. This subroutine is intended to > identify machines with a large exponent range, such as the Crays, and > redefine the underflow and overflow limits to be the square roots of > the values computed by DLAMCH. This subroutine is needed because > DLAMCH does not compensate for poor arithmetic in the upper half of > the exponent range, as is found on a Cray. > \endverbatim Arguments: ========== > \param[in,out] SMALL > \verbatim > SMALL is DOUBLE PRECISION > On entry, the underflow threshold as computed by DLAMCH. > On exit, if LOG10(LARGE) is sufficiently large, the square > root of SMALL, otherwise unchanged. > \endverbatim > > \param[in,out] LARGE > \verbatim > LARGE is DOUBLE PRECISION > On entry, the overflow threshold as computed by DLAMCH. > On exit, if LOG10(LARGE) is sufficiently large, the square > root of LARGE, otherwise unchanged. > \endverbatim Authors: ======== > \author Univ. of Tennessee > \author Univ. of California Berkeley > \author Univ. of Colorado Denver > \author NAG Ltd. > \date November 2011 > \ingroup auxOTHERauxiliary ===================================================================== Subroutine */ int igraphdlabad_(doublereal *small, doublereal *large) { /* Builtin functions */ double d_lg10(doublereal *), sqrt(doublereal); /* -- LAPACK auxiliary routine (version 3.4.0) -- -- LAPACK is a software package provided by Univ. of Tennessee, -- -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- November 2011 ===================================================================== If it looks like we're on a Cray, take the square root of SMALL and LARGE to avoid overflow and underflow problems. */ if (d_lg10(large) > 2e3) { *small = sqrt(*small); *large = sqrt(*large); } return 0; /* End of DLABAD */ } /* igraphdlabad_ */