Mercurial > octave-nkf

comparison libcruft/slatec-fn/asinh.f @ 7789:82be108cc558

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
First attempt at single precision tyeps * * * corrections to qrupdate single precision routines * * * prefer demotion to single over promotion to double * * * Add single precision support to log2 function * * * Trivial PROJECT file update * * * Cache optimized hermitian/transpose methods * * * Add tests for tranpose/hermitian and ChangeLog entry for new transpose code
author David Bateman <dbateman@free.fr>
date Sun, 27 Apr 2008 22:34:17 +0200
parents
children
comparison
equal deleted inserted replaced
7788:45f5faba05a2 7789:82be108cc558
1 *DECK ASINH
2 FUNCTION ASINH (X)
3 C***BEGIN PROLOGUE ASINH
4 C***PURPOSE Compute the arc hyperbolic sine.
5 C***LIBRARY SLATEC (FNLIB)
6 C***CATEGORY C4C
7 C***TYPE SINGLE PRECISION (ASINH-S, DASINH-D, CASINH-C)
8 C***KEYWORDS ARC HYPERBOLIC SINE, ASINH, ELEMENTARY FUNCTIONS, FNLIB,
9 C INVERSE HYPERBOLIC SINE
10 C***AUTHOR Fullerton, W., (LANL)
11 C***DESCRIPTION
12 C
13 C ASINH(X) computes the arc hyperbolic sine of X.
14 C
15 C Series for ASNH on the interval 0. to 1.00000D+00
16 C with weighted error 2.19E-17
17 C log weighted error 16.66
18 C significant figures required 15.60
19 C decimal places required 17.31
20 C
21 C***REFERENCES (NONE)
22 C***ROUTINES CALLED CSEVL, INITS, R1MACH
23 C***REVISION HISTORY (YYMMDD)
24 C 770401 DATE WRITTEN
25 C 890531 Changed all specific intrinsics to generic. (WRB)
26 C 890531 REVISION DATE from Version 3.2
27 C 891214 Prologue converted to Version 4.0 format. (BAB)
28 C***END PROLOGUE ASINH
29 DIMENSION ASNHCS(20)
30 LOGICAL FIRST
31 SAVE ALN2, ASNHCS, NTERMS, XMAX, SQEPS, FIRST
32 DATA ALN2 /0.6931471805 5994530942E0/
33 DATA ASNHCS( 1) / -.1282003991 1738186E0 /
34 DATA ASNHCS( 2) / -.0588117611 89951768E0 /
35 DATA ASNHCS( 3) / .0047274654 32212481E0 /
36 DATA ASNHCS( 4) / -.0004938363 16265361E0 /
37 DATA ASNHCS( 5) / .0000585062 07058557E0 /
38 DATA ASNHCS( 6) / -.0000074669 98328931E0 /
39 DATA ASNHCS( 7) / .0000010011 69358355E0 /
40 DATA ASNHCS( 8) / -.0000001390 35438587E0 /
41 DATA ASNHCS( 9) / .0000000198 23169483E0 /
42 DATA ASNHCS(10) / -.0000000028 84746841E0 /
43 DATA ASNHCS(11) / .0000000004 26729654E0 /
44 DATA ASNHCS(12) / -.0000000000 63976084E0 /
45 DATA ASNHCS(13) / .0000000000 09699168E0 /
46 DATA ASNHCS(14) / -.0000000000 01484427E0 /
47 DATA ASNHCS(15) / .0000000000 00229037E0 /
48 DATA ASNHCS(16) / -.0000000000 00035588E0 /
49 DATA ASNHCS(17) / .0000000000 00005563E0 /
50 DATA ASNHCS(18) / -.0000000000 00000874E0 /
51 DATA ASNHCS(19) / .0000000000 00000138E0 /
52 DATA ASNHCS(20) / -.0000000000 00000021E0 /
53 DATA FIRST /.TRUE./
54 C***FIRST EXECUTABLE STATEMENT ASINH
55 IF (FIRST) THEN
56 NTERMS = INITS (ASNHCS, 20, 0.1*R1MACH(3))
57 SQEPS = SQRT (R1MACH(3))
58 XMAX = 1.0/SQEPS
59 ENDIF
60 FIRST = .FALSE.
61 C
62 Y = ABS(X)
63 IF (Y.GT.1.0) GO TO 20
64 C
65 ASINH = X
66 IF (Y.GT.SQEPS) ASINH = X*(1.0 + CSEVL (2.*X*X-1., ASNHCS,NTERMS))
67 RETURN
68 C
69 20 IF (Y.LT.XMAX) ASINH = LOG (Y + SQRT(Y**2+1.))
70 IF (Y.GE.XMAX) ASINH = ALN2 + LOG(Y)
71 ASINH = SIGN (ASINH, X)
72 C
73 RETURN
74 END