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Diffstat (limited to 'src/math/e_acosh.c')
-rw-r--r-- | src/math/e_acosh.c | 59 |
1 files changed, 0 insertions, 59 deletions
diff --git a/src/math/e_acosh.c b/src/math/e_acosh.c deleted file mode 100644 index 8b454e75..00000000 --- a/src/math/e_acosh.c +++ /dev/null @@ -1,59 +0,0 @@ - -/* @(#)e_acosh.c 1.3 95/01/18 */ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunSoft, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - * - */ - -/* acosh(x) - * Method : - * Based on - * acosh(x) = log [ x + sqrt(x*x-1) ] - * we have - * acosh(x) := log(x)+ln2, if x is large; else - * acosh(x) := log(2x-1/(sqrt(x*x-1)+x)) if x>2; else - * acosh(x) := log1p(t+sqrt(2.0*t+t*t)); where t=x-1. - * - * Special cases: - * acosh(x) is NaN with signal if x<1. - * acosh(NaN) is NaN without signal. - */ - -#include <math.h> -#include "math_private.h" - -static const double -one = 1.0, -ln2 = 6.93147180559945286227e-01; /* 0x3FE62E42, 0xFEFA39EF */ - -double -acosh(double x) -{ - double t; - int32_t hx; - uint32_t lx; - EXTRACT_WORDS(hx,lx,x); - if(hx<0x3ff00000) { /* x < 1 */ - return (x-x)/(x-x); - } else if(hx >=0x41b00000) { /* x > 2**28 */ - if(hx >=0x7ff00000) { /* x is inf of NaN */ - return x+x; - } else - return log(x)+ln2; /* acosh(huge)=log(2x) */ - } else if(((hx-0x3ff00000)|lx)==0) { - return 0.0; /* acosh(1) = 0 */ - } else if (hx > 0x40000000) { /* 2**28 > x > 2 */ - t=x*x; - return log(2.0*x-one/(x+sqrt(t-one))); - } else { /* 1<x<2 */ - t = x-one; - return log1p(t+sqrt(2.0*t+t*t)); - } -} |