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/* eispack/epslon.f -- translated by f2c (version 20050501).
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 "v3p_netlib.h"
/*< double precision function epslon (x) >*/
doublereal epslon_(doublereal *x)
{
/* System generated locals */
doublereal ret_val, d__1;
/* Local variables */
doublereal a, b, c__, eps;
/*< double precision x >*/
/* estimate unit roundoff in quantities of size x. */
/*< double precision a,b,c,eps >*/
/* this program should function properly on all systems */
/* satisfying the following two assumptions, */
/* 1. the base used in representing floating point */
/* numbers is not a power of three. */
/* 2. the quantity a in statement 10 is represented to */
/* the accuracy used in floating point variables */
/* that are stored in memory. */
/* the statement number 10 and the go to 10 are intended to */
/* force optimizing compilers to generate code satisfying */
/* assumption 2. */
/* under these assumptions, it should be true that, */
/* a is not exactly equal to four-thirds, */
/* b has a zero for its last bit or digit, */
/* c is not exactly equal to one, */
/* eps measures the separation of 1.0 from */
/* the next larger floating point number. */
/* the developers of eispack would appreciate being informed */
/* about any systems where these assumptions do not hold. */
/* this version dated 4/6/83. */
/*< a = 4.0d0/3.0d0 >*/
a = 1.3333333333333333;
/*< 10 b = a - 1.0d0 >*/
L10:
b = a - 1.;
/*< c = b + b + b >*/
c__ = b + b + b;
/*< eps = dabs(c-1.0d0) >*/
eps = (d__1 = c__ - 1., abs(d__1));
/*< if (eps .eq. 0.0d0) go to 10 >*/
if (eps == 0.) {
goto L10;
}
/*< epslon = eps*dabs(x) >*/
ret_val = eps * abs(*x);
/*< return >*/
return ret_val;
/*< end >*/
} /* epslon_ */
#ifdef __cplusplus
}
#endif
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