Mercurial > octave-nkf
view libcruft/slatec-fn/gamr.f @ 7789:82be108cc558
First attempt at single precision tyeps
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corrections to qrupdate single precision routines
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prefer demotion to single over promotion to double
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Add single precision support to log2 function
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Trivial PROJECT file update
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Cache optimized hermitian/transpose methods
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Add tests for tranpose/hermitian and ChangeLog entry for new transpose code
author | David Bateman <dbateman@free.fr> |
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date | Sun, 27 Apr 2008 22:34:17 +0200 |
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*DECK GAMR FUNCTION GAMR (X) C***BEGIN PROLOGUE GAMR C***PURPOSE Compute the reciprocal of the Gamma function. C***LIBRARY SLATEC (FNLIB) C***CATEGORY C7A C***TYPE SINGLE PRECISION (GAMR-S, DGAMR-D, CGAMR-C) C***KEYWORDS FNLIB, RECIPROCAL GAMMA FUNCTION, SPECIAL FUNCTIONS C***AUTHOR Fullerton, W., (LANL) C***DESCRIPTION C C GAMR is a single precision function that evaluates the reciprocal C of the gamma function for single precision argument X. C C***REFERENCES (NONE) C***ROUTINES CALLED ALGAMS, GAMMA, XERCLR, XGETF, XSETF C***REVISION HISTORY (YYMMDD) C 770701 DATE WRITTEN C 861211 REVISION DATE from Version 3.2 C 891214 Prologue converted to Version 4.0 format. (BAB) C 900727 Added EXTERNAL statement. (WRB) C***END PROLOGUE GAMR EXTERNAL GAMMA C***FIRST EXECUTABLE STATEMENT GAMR GAMR = 0.0 IF (X.LE.0.0 .AND. AINT(X).EQ.X) RETURN C CALL XGETF (IROLD) CALL XSETF (1) IF (ABS(X).GT.10.0) GO TO 10 GAMR = 1.0/GAMMA(X) CALL XERCLR CALL XSETF (IROLD) RETURN C 10 CALL ALGAMS (X, ALNGX, SGNGX) CALL XERCLR CALL XSETF (IROLD) GAMR = SGNGX * EXP(-ALNGX) RETURN C END