From ef24de24a82fe681581cc130f342363c47c0969a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 7 Jun 2024 07:48:48 +0200 Subject: Merging upstream version 1.75.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/libm-0.1.4/src/math/log1p.rs | 144 ------------------------------------ 1 file changed, 144 deletions(-) delete mode 100644 vendor/libm-0.1.4/src/math/log1p.rs (limited to 'vendor/libm-0.1.4/src/math/log1p.rs') diff --git a/vendor/libm-0.1.4/src/math/log1p.rs b/vendor/libm-0.1.4/src/math/log1p.rs deleted file mode 100644 index cd7045ac9..000000000 --- a/vendor/libm-0.1.4/src/math/log1p.rs +++ /dev/null @@ -1,144 +0,0 @@ -/* origin: FreeBSD /usr/src/lib/msun/src/s_log1p.c */ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunPro, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ -/* double log1p(double x) - * Return the natural logarithm of 1+x. - * - * Method : - * 1. Argument Reduction: find k and f such that - * 1+x = 2^k * (1+f), - * where sqrt(2)/2 < 1+f < sqrt(2) . - * - * Note. If k=0, then f=x is exact. However, if k!=0, then f - * may not be representable exactly. In that case, a correction - * term is need. Let u=1+x rounded. Let c = (1+x)-u, then - * log(1+x) - log(u) ~ c/u. Thus, we proceed to compute log(u), - * and add back the correction term c/u. - * (Note: when x > 2**53, one can simply return log(x)) - * - * 2. Approximation of log(1+f): See log.c - * - * 3. Finally, log1p(x) = k*ln2 + log(1+f) + c/u. See log.c - * - * Special cases: - * log1p(x) is NaN with signal if x < -1 (including -INF) ; - * log1p(+INF) is +INF; log1p(-1) is -INF with signal; - * log1p(NaN) is that NaN with no signal. - * - * Accuracy: - * according to an error analysis, the error is always less than - * 1 ulp (unit in the last place). - * - * Constants: - * The hexadecimal values are the intended ones for the following - * constants. The decimal values may be used, provided that the - * compiler will convert from decimal to binary accurately enough - * to produce the hexadecimal values shown. - * - * Note: Assuming log() return accurate answer, the following - * algorithm can be used to compute log1p(x) to within a few ULP: - * - * u = 1+x; - * if(u==1.0) return x ; else - * return log(u)*(x/(u-1.0)); - * - * See HP-15C Advanced Functions Handbook, p.193. - */ - -use core::f64; - -const LN2_HI: f64 = 6.93147180369123816490e-01; /* 3fe62e42 fee00000 */ -const LN2_LO: f64 = 1.90821492927058770002e-10; /* 3dea39ef 35793c76 */ -const LG1: f64 = 6.666666666666735130e-01; /* 3FE55555 55555593 */ -const LG2: f64 = 3.999999999940941908e-01; /* 3FD99999 9997FA04 */ -const LG3: f64 = 2.857142874366239149e-01; /* 3FD24924 94229359 */ -const LG4: f64 = 2.222219843214978396e-01; /* 3FCC71C5 1D8E78AF */ -const LG5: f64 = 1.818357216161805012e-01; /* 3FC74664 96CB03DE */ -const LG6: f64 = 1.531383769920937332e-01; /* 3FC39A09 D078C69F */ -const LG7: f64 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */ - -#[inline] -#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] -pub fn log1p(x: f64) -> f64 { - let mut ui: u64 = x.to_bits(); - let hfsq: f64; - let mut f: f64 = 0.; - let mut c: f64 = 0.; - let s: f64; - let z: f64; - let r: f64; - let w: f64; - let t1: f64; - let t2: f64; - let dk: f64; - let hx: u32; - let mut hu: u32; - let mut k: i32; - - hx = (ui >> 32) as u32; - k = 1; - if hx < 0x3fda827a || (hx >> 31) > 0 { - /* 1+x < sqrt(2)+ */ - if hx >= 0xbff00000 { - /* x <= -1.0 */ - if x == -1. { - return x / 0.0; /* log1p(-1) = -inf */ - } - return (x - x) / 0.0; /* log1p(x<-1) = NaN */ - } - if hx << 1 < 0x3ca00000 << 1 { - /* |x| < 2**-53 */ - /* underflow if subnormal */ - if (hx & 0x7ff00000) == 0 { - force_eval!(x as f32); - } - return x; - } - if hx <= 0xbfd2bec4 { - /* sqrt(2)/2- <= 1+x < sqrt(2)+ */ - k = 0; - c = 0.; - f = x; - } - } else if hx >= 0x7ff00000 { - return x; - } - if k > 0 { - ui = (1. + x).to_bits(); - hu = (ui >> 32) as u32; - hu += 0x3ff00000 - 0x3fe6a09e; - k = (hu >> 20) as i32 - 0x3ff; - /* correction term ~ log(1+x)-log(u), avoid underflow in c/u */ - if k < 54 { - c = if k >= 2 { - 1. - (f64::from_bits(ui) - x) - } else { - x - (f64::from_bits(ui) - 1.) - }; - c /= f64::from_bits(ui); - } else { - c = 0.; - } - /* reduce u into [sqrt(2)/2, sqrt(2)] */ - hu = (hu & 0x000fffff) + 0x3fe6a09e; - ui = (hu as u64) << 32 | (ui & 0xffffffff); - f = f64::from_bits(ui) - 1.; - } - hfsq = 0.5 * f * f; - s = f / (2.0 + f); - z = s * s; - w = z * z; - t1 = w * (LG2 + w * (LG4 + w * LG6)); - t2 = z * (LG1 + w * (LG3 + w * (LG5 + w * LG7))); - r = t2 + t1; - dk = k as f64; - s * (hfsq + r) + (dk * LN2_LO + c) - hfsq + f + dk * LN2_HI -} -- cgit v1.2.3