agent_compositor_test/references/igraph-1.0.1/vendor/lapack/ieeeck.c

/*  -- translated by f2c (version 20240504).
   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 IEEECK   

    =========== DOCUMENTATION ===========   

   Online html documentation available at   
              http://www.netlib.org/lapack/explore-html/   

   > \htmlonly   
   > Download IEEECK + dependencies   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ieeeck.
f">   
   > [TGZ]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ieeeck.
f">   
   > [ZIP]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ieeeck.
f">   
   > [TXT]</a>   
   > \endhtmlonly   

    Definition:   
    ===========   

         INTEGER          FUNCTION IEEECK( ISPEC, ZERO, ONE )   

         INTEGER            ISPEC   
         REAL               ONE, ZERO   


   > \par Purpose:   
    =============   
   >   
   > \verbatim   
   >   
   > IEEECK is called from the ILAENV to verify that Infinity and   
   > possibly NaN arithmetic is safe (i.e. will not trap).   
   > \endverbatim   

    Arguments:   
    ==========   

   > \param[in] ISPEC   
   > \verbatim   
   >          ISPEC is INTEGER   
   >          Specifies whether to test just for inifinity arithmetic   
   >          or whether to test for infinity and NaN arithmetic.   
   >          = 0: Verify infinity arithmetic only.   
   >          = 1: Verify infinity and NaN arithmetic.   
   > \endverbatim   
   >   
   > \param[in] ZERO   
   > \verbatim   
   >          ZERO is REAL   
   >          Must contain the value 0.0   
   >          This is passed to prevent the compiler from optimizing   
   >          away this code.   
   > \endverbatim   
   >   
   > \param[in] ONE   
   > \verbatim   
   >          ONE is REAL   
   >          Must contain the value 1.0   
   >          This is passed to prevent the compiler from optimizing   
   >          away this code.   
   >   
   >  RETURN VALUE:  INTEGER   
   >          = 0:  Arithmetic failed to produce the correct answers   
   >          = 1:  Arithmetic produced the correct answers   
   > \endverbatim   

    Authors:   
    ========   

   > \author Univ. of Tennessee   
   > \author Univ. of California Berkeley   
   > \author Univ. of Colorado Denver   
   > \author NAG Ltd.   

   > \date November 2011   

   > \ingroup auxOTHERauxiliary   

    ===================================================================== */
integer igraphieeeck_(integer *ispec, real *zero, real *one)
{
    /* System generated locals */
    integer ret_val;

    /* Local variables */
    real nan1, nan2, nan3, nan4, nan5, nan6, neginf, posinf, negzro, newzro;


/*  -- 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   


    ===================================================================== */

    ret_val = 1;

    posinf = *one / *zero;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }

    neginf = -(*one) / *zero;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    negzro = *one / (neginf + *one);
    if (negzro != *zero) {
	ret_val = 0;
	return ret_val;
    }

    neginf = *one / negzro;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    newzro = negzro + *zero;
    if (newzro != *zero) {
	ret_val = 0;
	return ret_val;
    }

    posinf = *one / newzro;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }

    neginf *= posinf;
    if (neginf >= *zero) {
	ret_val = 0;
	return ret_val;
    }

    posinf *= posinf;
    if (posinf <= *one) {
	ret_val = 0;
	return ret_val;
    }




/*     Return if we were only asked to check infinity arithmetic */

    if (*ispec == 0) {
	return ret_val;
    }

    nan1 = posinf + neginf;

    nan2 = posinf / neginf;

    nan3 = posinf / posinf;

    nan4 = posinf * *zero;

    nan5 = neginf * negzro;

    nan6 = nan5 * *zero;

    if (nan1 == nan1) {
	ret_val = 0;
	return ret_val;
    }

    if (nan2 == nan2) {
	ret_val = 0;
	return ret_val;
    }

    if (nan3 == nan3) {
	ret_val = 0;
	return ret_val;
    }

    if (nan4 == nan4) {
	ret_val = 0;
	return ret_val;
    }

    if (nan5 == nan5) {
	ret_val = 0;
	return ret_val;
    }

    if (nan6 == nan6) {
	ret_val = 0;
	return ret_val;
    }

    return ret_val;
} /* igraphieeeck_ */