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/* d9lgmc.f -- translated by f2c (version 20041007).
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
*/
/** This routine has been editted to be thread safe **/
#define V3P_NETLIB_SRC
#include "v3p_netlib.h"
/* Table of constant values */
static integer c__15 = 15;
static integer c__3 = 3;
static integer c__1 = 1;
static integer c__2 = 2;
/* DECK D9LGMC */
doublereal d9lgmc_(doublereal *x)
{
/* Initialized data */
static doublereal algmcs[15] = { .1666389480451863247205729650822,
-1.384948176067563840732986059135e-5,
9.810825646924729426157171547487e-9,
-1.809129475572494194263306266719e-11,
6.221098041892605227126015543416e-14,
-3.399615005417721944303330599666e-16,
2.683181998482698748957538846666e-18,
-2.868042435334643284144622399999e-20,
3.962837061046434803679306666666e-22,
-6.831888753985766870111999999999e-24,
1.429227355942498147573333333333e-25,
-3.547598158101070547199999999999e-27,1.025680058010470912e-28,
-3.401102254316748799999999999999e-30,
1.276642195630062933333333333333e-31 };
// static logical first = TRUE_;
/* System generated locals */
real r__1;
doublereal ret_val, d__1, d__2;
/* Builtin functions */
double sqrt(doublereal), log(doublereal), exp(doublereal);
/* Local variables */
/* static */ doublereal xbig, xmax;
/* static */ integer nalgm;
extern doublereal d1mach_(integer *), dcsevl_(doublereal *, doublereal *,
integer *);
extern integer initds_(doublereal *, integer *, real *);
extern /* Subroutine */ int xermsg_(char *, char *, char *, integer *,
integer *, ftnlen, ftnlen, ftnlen);
/* ***BEGIN PROLOGUE D9LGMC */
/* ***SUBSIDIARY */
/* ***PURPOSE Compute the log Gamma correction factor so that */
/* LOG(DGAMMA(X)) = LOG(SQRT(2*PI)) + (X-5.)*LOG(X) - X */
/* + D9LGMC(X). */
/* ***LIBRARY SLATEC (FNLIB) */
/* ***CATEGORY C7E */
/* ***TYPE DOUBLE PRECISION (R9LGMC-S, D9LGMC-D, C9LGMC-C) */
/* ***KEYWORDS COMPLETE GAMMA FUNCTION, CORRECTION TERM, FNLIB, */
/* LOG GAMMA, LOGARITHM, SPECIAL FUNCTIONS */
/* ***AUTHOR Fullerton, W., (LANL) */
/* ***DESCRIPTION */
/* Compute the log gamma correction factor for X .GE. 10. so that */
/* LOG (DGAMMA(X)) = LOG(SQRT(2*PI)) + (X-.5)*LOG(X) - X + D9lGMC(X) */
/* Series for ALGM on the interval 0. to 1.00000E-02 */
/* with weighted error 1.28E-31 */
/* log weighted error 30.89 */
/* significant figures required 29.81 */
/* decimal places required 31.48 */
/* ***REFERENCES (NONE) */
/* ***ROUTINES CALLED D1MACH, DCSEVL, INITDS, XERMSG */
/* ***REVISION HISTORY (YYMMDD) */
/* 770601 DATE WRITTEN */
/* 890531 Changed all specific intrinsics to generic. (WRB) */
/* 890531 REVISION DATE from Version 3.2 */
/* 891214 Prologue converted to Version 4.0 format. (BAB) */
/* 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ) */
/* 900720 Routine changed from user-callable to subsidiary. (WRB) */
/* ***END PROLOGUE D9LGMC */
/* ***FIRST EXECUTABLE STATEMENT D9LGMC */
// d1mach has been made thread safe, so there is no need for the
// statics in determining these values
// if (first) {
// r__1 = (real) d1mach_(&c__3);
// nalgm = initds_(algmcs, &c__15, &r__1);
// xbig = 1. / sqrt(d1mach_(&c__3));
// /* Computing MIN */
// d__1 = log(d1mach_(&c__2) / 12.), d__2 = -log(d1mach_(&c__1) * 12.);
// xmax = exp((min(d__1,d__2)));
// }
// first = FALSE_;
r__1 = (real) d1mach_(&c__3);
nalgm = initds_(algmcs, &c__15, &r__1);
xbig = 1. / sqrt(d1mach_(&c__3));
/* Computing MIN */
d__1 = log(d1mach_(&c__2) / 12.), d__2 = -log(d1mach_(&c__1) * 12.);
xmax = exp((min(d__1,d__2)));
if (*x < 10.) {
xermsg_("SLATEC", "D9LGMC", "X MUST BE GE 10", &c__1, &c__2, (ftnlen)
6, (ftnlen)6, (ftnlen)15);
}
if (*x >= xmax) {
goto L20;
}
ret_val = 1. / (*x * 12.);
if (*x < xbig) {
/* Computing 2nd power */
d__2 = 10. / *x;
d__1 = d__2 * d__2 * 2. - 1.;
ret_val = dcsevl_(&d__1, algmcs, &nalgm) / *x;
}
return ret_val;
L20:
ret_val = 0.;
xermsg_("SLATEC", "D9LGMC", "X SO BIG D9LGMC UNDERFLOWS", &c__2, &c__1, (
ftnlen)6, (ftnlen)6, (ftnlen)26);
return ret_val;
} /* d9lgmc_ */
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