| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/libm-0.2.7/src/math/pow.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>pow.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../libm/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../libm/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| <span id="545">545</span> |
| <span id="546">546</span> |
| <span id="547">547</span> |
| <span id="548">548</span> |
| <span id="549">549</span> |
| <span id="550">550</span> |
| <span id="551">551</span> |
| <span id="552">552</span> |
| <span id="553">553</span> |
| <span id="554">554</span> |
| <span id="555">555</span> |
| <span id="556">556</span> |
| <span id="557">557</span> |
| <span id="558">558</span> |
| <span id="559">559</span> |
| <span id="560">560</span> |
| <span id="561">561</span> |
| <span id="562">562</span> |
| <span id="563">563</span> |
| <span id="564">564</span> |
| <span id="565">565</span> |
| <span id="566">566</span> |
| <span id="567">567</span> |
| <span id="568">568</span> |
| <span id="569">569</span> |
| <span id="570">570</span> |
| <span id="571">571</span> |
| <span id="572">572</span> |
| <span id="573">573</span> |
| <span id="574">574</span> |
| <span id="575">575</span> |
| <span id="576">576</span> |
| <span id="577">577</span> |
| <span id="578">578</span> |
| <span id="579">579</span> |
| <span id="580">580</span> |
| <span id="581">581</span> |
| <span id="582">582</span> |
| <span id="583">583</span> |
| <span id="584">584</span> |
| <span id="585">585</span> |
| <span id="586">586</span> |
| <span id="587">587</span> |
| <span id="588">588</span> |
| <span id="589">589</span> |
| <span id="590">590</span> |
| <span id="591">591</span> |
| <span id="592">592</span> |
| <span id="593">593</span> |
| <span id="594">594</span> |
| <span id="595">595</span> |
| <span id="596">596</span> |
| <span id="597">597</span> |
| <span id="598">598</span> |
| <span id="599">599</span> |
| <span id="600">600</span> |
| <span id="601">601</span> |
| <span id="602">602</span> |
| <span id="603">603</span> |
| <span id="604">604</span> |
| <span id="605">605</span> |
| <span id="606">606</span> |
| <span id="607">607</span> |
| <span id="608">608</span> |
| <span id="609">609</span> |
| <span id="610">610</span> |
| <span id="611">611</span> |
| <span id="612">612</span> |
| <span id="613">613</span> |
| <span id="614">614</span> |
| <span id="615">615</span> |
| <span id="616">616</span> |
| <span id="617">617</span> |
| <span id="618">618</span> |
| <span id="619">619</span> |
| <span id="620">620</span> |
| <span id="621">621</span> |
| <span id="622">622</span> |
| <span id="623">623</span> |
| <span id="624">624</span> |
| <span id="625">625</span> |
| <span id="626">626</span> |
| <span id="627">627</span> |
| <span id="628">628</span> |
| <span id="629">629</span> |
| <span id="630">630</span> |
| <span id="631">631</span> |
| <span id="632">632</span> |
| <span id="633">633</span> |
| <span id="634">634</span> |
| <span id="635">635</span> |
| <span id="636">636</span> |
| <span id="637">637</span> |
| </pre><pre class="rust"><code><span class="comment">/* origin: FreeBSD /usr/src/lib/msun/src/e_pow.c */ |
| /* |
| * ==================================================== |
| * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| // pow(x,y) return x**y |
| // |
| // n |
| // Method: Let x = 2 * (1+f) |
| // 1. Compute and return log2(x) in two pieces: |
| // log2(x) = w1 + w2, |
| // where w1 has 53-24 = 29 bit trailing zeros. |
| // 2. Perform y*log2(x) = n+y' by simulating muti-precision |
| // arithmetic, where |y'|<=0.5. |
| // 3. Return x**y = 2**n*exp(y'*log2) |
| // |
| // Special cases: |
| // 1. (anything) ** 0 is 1 |
| // 2. 1 ** (anything) is 1 |
| // 3. (anything except 1) ** NAN is NAN |
| // 4. NAN ** (anything except 0) is NAN |
| // 5. +-(|x| > 1) ** +INF is +INF |
| // 6. +-(|x| > 1) ** -INF is +0 |
| // 7. +-(|x| < 1) ** +INF is +0 |
| // 8. +-(|x| < 1) ** -INF is +INF |
| // 9. -1 ** +-INF is 1 |
| // 10. +0 ** (+anything except 0, NAN) is +0 |
| // 11. -0 ** (+anything except 0, NAN, odd integer) is +0 |
| // 12. +0 ** (-anything except 0, NAN) is +INF, raise divbyzero |
| // 13. -0 ** (-anything except 0, NAN, odd integer) is +INF, raise divbyzero |
| // 14. -0 ** (+odd integer) is -0 |
| // 15. -0 ** (-odd integer) is -INF, raise divbyzero |
| // 16. +INF ** (+anything except 0,NAN) is +INF |
| // 17. +INF ** (-anything except 0,NAN) is +0 |
| // 18. -INF ** (+odd integer) is -INF |
| // 19. -INF ** (anything) = -0 ** (-anything), (anything except odd integer) |
| // 20. (anything) ** 1 is (anything) |
| // 21. (anything) ** -1 is 1/(anything) |
| // 22. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer) |
| // 23. (-anything except 0 and inf) ** (non-integer) is NAN |
| // |
| // Accuracy: |
| // pow(x,y) returns x**y nearly rounded. In particular |
| // pow(integer,integer) |
| // always returns the correct integer provided it is |
| // representable. |
| // |
| // 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. |
| // |
| </span><span class="kw">use super</span>::{fabs, get_high_word, scalbn, sqrt, with_set_high_word, with_set_low_word}; |
| |
| <span class="kw">const </span>BP: [f64; <span class="number">2</span>] = [<span class="number">1.0</span>, <span class="number">1.5</span>]; |
| <span class="kw">const </span>DP_H: [f64; <span class="number">2</span>] = [<span class="number">0.0</span>, <span class="number">5.84962487220764160156e-01</span>]; <span class="comment">/* 0x3fe2b803_40000000 */ |
| </span><span class="kw">const </span>DP_L: [f64; <span class="number">2</span>] = [<span class="number">0.0</span>, <span class="number">1.35003920212974897128e-08</span>]; <span class="comment">/* 0x3E4CFDEB, 0x43CFD006 */ |
| </span><span class="kw">const </span>TWO53: f64 = <span class="number">9007199254740992.0</span>; <span class="comment">/* 0x43400000_00000000 */ |
| </span><span class="kw">const </span>HUGE: f64 = <span class="number">1.0e300</span>; |
| <span class="kw">const </span>TINY: f64 = <span class="number">1.0e-300</span>; |
| |
| <span class="comment">// poly coefs for (3/2)*(log(x)-2s-2/3*s**3: |
| </span><span class="kw">const </span>L1: f64 = <span class="number">5.99999999999994648725e-01</span>; <span class="comment">/* 0x3fe33333_33333303 */ |
| </span><span class="kw">const </span>L2: f64 = <span class="number">4.28571428578550184252e-01</span>; <span class="comment">/* 0x3fdb6db6_db6fabff */ |
| </span><span class="kw">const </span>L3: f64 = <span class="number">3.33333329818377432918e-01</span>; <span class="comment">/* 0x3fd55555_518f264d */ |
| </span><span class="kw">const </span>L4: f64 = <span class="number">2.72728123808534006489e-01</span>; <span class="comment">/* 0x3fd17460_a91d4101 */ |
| </span><span class="kw">const </span>L5: f64 = <span class="number">2.30660745775561754067e-01</span>; <span class="comment">/* 0x3fcd864a_93c9db65 */ |
| </span><span class="kw">const </span>L6: f64 = <span class="number">2.06975017800338417784e-01</span>; <span class="comment">/* 0x3fca7e28_4a454eef */ |
| </span><span class="kw">const </span>P1: f64 = <span class="number">1.66666666666666019037e-01</span>; <span class="comment">/* 0x3fc55555_5555553e */ |
| </span><span class="kw">const </span>P2: f64 = -<span class="number">2.77777777770155933842e-03</span>; <span class="comment">/* 0xbf66c16c_16bebd93 */ |
| </span><span class="kw">const </span>P3: f64 = <span class="number">6.61375632143793436117e-05</span>; <span class="comment">/* 0x3f11566a_af25de2c */ |
| </span><span class="kw">const </span>P4: f64 = -<span class="number">1.65339022054652515390e-06</span>; <span class="comment">/* 0xbebbbd41_c5d26bf1 */ |
| </span><span class="kw">const </span>P5: f64 = <span class="number">4.13813679705723846039e-08</span>; <span class="comment">/* 0x3e663769_72bea4d0 */ |
| </span><span class="kw">const </span>LG2: f64 = <span class="number">6.93147180559945286227e-01</span>; <span class="comment">/* 0x3fe62e42_fefa39ef */ |
| </span><span class="kw">const </span>LG2_H: f64 = <span class="number">6.93147182464599609375e-01</span>; <span class="comment">/* 0x3fe62e43_00000000 */ |
| </span><span class="kw">const </span>LG2_L: f64 = -<span class="number">1.90465429995776804525e-09</span>; <span class="comment">/* 0xbe205c61_0ca86c39 */ |
| </span><span class="kw">const </span>OVT: f64 = <span class="number">8.0085662595372944372e-017</span>; <span class="comment">/* -(1024-log2(ovfl+.5ulp)) */ |
| </span><span class="kw">const </span>CP: f64 = <span class="number">9.61796693925975554329e-01</span>; <span class="comment">/* 0x3feec709_dc3a03fd =2/(3ln2) */ |
| </span><span class="kw">const </span>CP_H: f64 = <span class="number">9.61796700954437255859e-01</span>; <span class="comment">/* 0x3feec709_e0000000 =(float)cp */ |
| </span><span class="kw">const </span>CP_L: f64 = -<span class="number">7.02846165095275826516e-09</span>; <span class="comment">/* 0xbe3e2fe0_145b01f5 =tail of cp_h*/ |
| </span><span class="kw">const </span>IVLN2: f64 = <span class="number">1.44269504088896338700e+00</span>; <span class="comment">/* 0x3ff71547_652b82fe =1/ln2 */ |
| </span><span class="kw">const </span>IVLN2_H: f64 = <span class="number">1.44269502162933349609e+00</span>; <span class="comment">/* 0x3ff71547_60000000 =24b 1/ln2*/ |
| </span><span class="kw">const </span>IVLN2_L: f64 = <span class="number">1.92596299112661746887e-08</span>; <span class="comment">/* 0x3e54ae0b_f85ddf44 =1/ln2 tail*/ |
| |
| </span><span class="attribute">#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| </span><span class="kw">pub fn </span>pow(x: f64, y: f64) -> f64 { |
| <span class="kw">let </span>t1: f64; |
| <span class="kw">let </span>t2: f64; |
| |
| <span class="kw">let </span>(hx, lx): (i32, u32) = ((x.to_bits() >> <span class="number">32</span>) <span class="kw">as </span>i32, x.to_bits() <span class="kw">as </span>u32); |
| <span class="kw">let </span>(hy, ly): (i32, u32) = ((y.to_bits() >> <span class="number">32</span>) <span class="kw">as </span>i32, y.to_bits() <span class="kw">as </span>u32); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>ix: i32 = (hx & <span class="number">0x7fffffff</span>) <span class="kw">as </span>i32; |
| <span class="kw">let </span>iy: i32 = (hy & <span class="number">0x7fffffff</span>) <span class="kw">as </span>i32; |
| |
| <span class="comment">/* x**0 = 1, even if x is NaN */ |
| </span><span class="kw">if </span>((iy <span class="kw">as </span>u32) | ly) == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="number">1.0</span>; |
| } |
| |
| <span class="comment">/* 1**y = 1, even if y is NaN */ |
| </span><span class="kw">if </span>hx == <span class="number">0x3ff00000 </span>&& lx == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="number">1.0</span>; |
| } |
| |
| <span class="comment">/* NaN if either arg is NaN */ |
| </span><span class="kw">if </span>ix > <span class="number">0x7ff00000 |
| </span>|| (ix == <span class="number">0x7ff00000 </span>&& lx != <span class="number">0</span>) |
| || iy > <span class="number">0x7ff00000 |
| </span>|| (iy == <span class="number">0x7ff00000 </span>&& ly != <span class="number">0</span>) |
| { |
| <span class="kw">return </span>x + y; |
| } |
| |
| <span class="comment">/* determine if y is an odd int when x < 0 |
| * yisint = 0 ... y is not an integer |
| * yisint = 1 ... y is an odd int |
| * yisint = 2 ... y is an even int |
| */ |
| </span><span class="kw">let </span><span class="kw-2">mut </span>yisint: i32 = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>k: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>j: i32; |
| <span class="kw">if </span>hx < <span class="number">0 </span>{ |
| <span class="kw">if </span>iy >= <span class="number">0x43400000 </span>{ |
| yisint = <span class="number">2</span>; <span class="comment">/* even integer y */ |
| </span>} <span class="kw">else if </span>iy >= <span class="number">0x3ff00000 </span>{ |
| k = (iy >> <span class="number">20</span>) - <span class="number">0x3ff</span>; <span class="comment">/* exponent */ |
| |
| </span><span class="kw">if </span>k > <span class="number">20 </span>{ |
| j = (ly >> (<span class="number">52 </span>- k)) <span class="kw">as </span>i32; |
| |
| <span class="kw">if </span>(j << (<span class="number">52 </span>- k)) == (ly <span class="kw">as </span>i32) { |
| yisint = <span class="number">2 </span>- (j & <span class="number">1</span>); |
| } |
| } <span class="kw">else if </span>ly == <span class="number">0 </span>{ |
| j = iy >> (<span class="number">20 </span>- k); |
| |
| <span class="kw">if </span>(j << (<span class="number">20 </span>- k)) == iy { |
| yisint = <span class="number">2 </span>- (j & <span class="number">1</span>); |
| } |
| } |
| } |
| } |
| |
| <span class="kw">if </span>ly == <span class="number">0 </span>{ |
| <span class="comment">/* special value of y */ |
| </span><span class="kw">if </span>iy == <span class="number">0x7ff00000 </span>{ |
| <span class="comment">/* y is +-inf */ |
| |
| </span><span class="kw">return if </span>((ix - <span class="number">0x3ff00000</span>) | (lx <span class="kw">as </span>i32)) == <span class="number">0 </span>{ |
| <span class="comment">/* (-1)**+-inf is 1 */ |
| </span><span class="number">1.0 |
| </span>} <span class="kw">else if </span>ix >= <span class="number">0x3ff00000 </span>{ |
| <span class="comment">/* (|x|>1)**+-inf = inf,0 */ |
| </span><span class="kw">if </span>hy >= <span class="number">0 </span>{ |
| y |
| } <span class="kw">else </span>{ |
| <span class="number">0.0 |
| </span>} |
| } <span class="kw">else </span>{ |
| <span class="comment">/* (|x|<1)**+-inf = 0,inf */ |
| </span><span class="kw">if </span>hy >= <span class="number">0 </span>{ |
| <span class="number">0.0 |
| </span>} <span class="kw">else </span>{ |
| -y |
| } |
| }; |
| } |
| |
| <span class="kw">if </span>iy == <span class="number">0x3ff00000 </span>{ |
| <span class="comment">/* y is +-1 */ |
| </span><span class="kw">return if </span>hy >= <span class="number">0 </span>{ x } <span class="kw">else </span>{ <span class="number">1.0 </span>/ x }; |
| } |
| |
| <span class="kw">if </span>hy == <span class="number">0x40000000 </span>{ |
| <span class="comment">/* y is 2 */ |
| </span><span class="kw">return </span>x * x; |
| } |
| |
| <span class="kw">if </span>hy == <span class="number">0x3fe00000 </span>{ |
| <span class="comment">/* y is 0.5 */ |
| </span><span class="kw">if </span>hx >= <span class="number">0 </span>{ |
| <span class="comment">/* x >= +0 */ |
| </span><span class="kw">return </span>sqrt(x); |
| } |
| } |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>ax: f64 = fabs(x); |
| <span class="kw">if </span>lx == <span class="number">0 </span>{ |
| <span class="comment">/* special value of x */ |
| </span><span class="kw">if </span>ix == <span class="number">0x7ff00000 </span>|| ix == <span class="number">0 </span>|| ix == <span class="number">0x3ff00000 </span>{ |
| <span class="comment">/* x is +-0,+-inf,+-1 */ |
| </span><span class="kw">let </span><span class="kw-2">mut </span>z: f64 = ax; |
| |
| <span class="kw">if </span>hy < <span class="number">0 </span>{ |
| <span class="comment">/* z = (1/|x|) */ |
| </span>z = <span class="number">1.0 </span>/ z; |
| } |
| |
| <span class="kw">if </span>hx < <span class="number">0 </span>{ |
| <span class="kw">if </span>((ix - <span class="number">0x3ff00000</span>) | yisint) == <span class="number">0 </span>{ |
| z = (z - z) / (z - z); <span class="comment">/* (-1)**non-int is NaN */ |
| </span>} <span class="kw">else if </span>yisint == <span class="number">1 </span>{ |
| z = -z; <span class="comment">/* (x<0)**odd = -(|x|**odd) */ |
| </span>} |
| } |
| |
| <span class="kw">return </span>z; |
| } |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>s: f64 = <span class="number">1.0</span>; <span class="comment">/* sign of result */ |
| </span><span class="kw">if </span>hx < <span class="number">0 </span>{ |
| <span class="kw">if </span>yisint == <span class="number">0 </span>{ |
| <span class="comment">/* (x<0)**(non-int) is NaN */ |
| </span><span class="kw">return </span>(x - x) / (x - x); |
| } |
| |
| <span class="kw">if </span>yisint == <span class="number">1 </span>{ |
| <span class="comment">/* (x<0)**(odd int) */ |
| </span>s = -<span class="number">1.0</span>; |
| } |
| } |
| |
| <span class="comment">/* |y| is HUGE */ |
| </span><span class="kw">if </span>iy > <span class="number">0x41e00000 </span>{ |
| <span class="comment">/* if |y| > 2**31 */ |
| </span><span class="kw">if </span>iy > <span class="number">0x43f00000 </span>{ |
| <span class="comment">/* if |y| > 2**64, must o/uflow */ |
| </span><span class="kw">if </span>ix <= <span class="number">0x3fefffff </span>{ |
| <span class="kw">return if </span>hy < <span class="number">0 </span>{ HUGE * HUGE } <span class="kw">else </span>{ TINY * TINY }; |
| } |
| |
| <span class="kw">if </span>ix >= <span class="number">0x3ff00000 </span>{ |
| <span class="kw">return if </span>hy > <span class="number">0 </span>{ HUGE * HUGE } <span class="kw">else </span>{ TINY * TINY }; |
| } |
| } |
| |
| <span class="comment">/* over/underflow if x is not close to one */ |
| </span><span class="kw">if </span>ix < <span class="number">0x3fefffff </span>{ |
| <span class="kw">return if </span>hy < <span class="number">0 </span>{ |
| s * HUGE * HUGE |
| } <span class="kw">else </span>{ |
| s * TINY * TINY |
| }; |
| } |
| <span class="kw">if </span>ix > <span class="number">0x3ff00000 </span>{ |
| <span class="kw">return if </span>hy > <span class="number">0 </span>{ |
| s * HUGE * HUGE |
| } <span class="kw">else </span>{ |
| s * TINY * TINY |
| }; |
| } |
| |
| <span class="comment">/* now |1-x| is TINY <= 2**-20, suffice to compute |
| log(x) by x-x^2/2+x^3/3-x^4/4 */ |
| </span><span class="kw">let </span>t: f64 = ax - <span class="number">1.0</span>; <span class="comment">/* t has 20 trailing zeros */ |
| </span><span class="kw">let </span>w: f64 = (t * t) * (<span class="number">0.5 </span>- t * (<span class="number">0.3333333333333333333333 </span>- t * <span class="number">0.25</span>)); |
| <span class="kw">let </span>u: f64 = IVLN2_H * t; <span class="comment">/* ivln2_h has 21 sig. bits */ |
| </span><span class="kw">let </span>v: f64 = t * IVLN2_L - w * IVLN2; |
| t1 = with_set_low_word(u + v, <span class="number">0</span>); |
| t2 = v - (t1 - u); |
| } <span class="kw">else </span>{ |
| <span class="comment">// double ss,s2,s_h,s_l,t_h,t_l; |
| </span><span class="kw">let </span><span class="kw-2">mut </span>n: i32 = <span class="number">0</span>; |
| |
| <span class="kw">if </span>ix < <span class="number">0x00100000 </span>{ |
| <span class="comment">/* take care subnormal number */ |
| </span>ax <span class="kw-2">*</span>= TWO53; |
| n -= <span class="number">53</span>; |
| ix = get_high_word(ax) <span class="kw">as </span>i32; |
| } |
| |
| n += (ix >> <span class="number">20</span>) - <span class="number">0x3ff</span>; |
| j = ix & <span class="number">0x000fffff</span>; |
| |
| <span class="comment">/* determine interval */ |
| </span><span class="kw">let </span>k: i32; |
| ix = j | <span class="number">0x3ff00000</span>; <span class="comment">/* normalize ix */ |
| </span><span class="kw">if </span>j <= <span class="number">0x3988E </span>{ |
| <span class="comment">/* |x|<sqrt(3/2) */ |
| </span>k = <span class="number">0</span>; |
| } <span class="kw">else if </span>j < <span class="number">0xBB67A </span>{ |
| <span class="comment">/* |x|<sqrt(3) */ |
| </span>k = <span class="number">1</span>; |
| } <span class="kw">else </span>{ |
| k = <span class="number">0</span>; |
| n += <span class="number">1</span>; |
| ix -= <span class="number">0x00100000</span>; |
| } |
| ax = with_set_high_word(ax, ix <span class="kw">as </span>u32); |
| |
| <span class="comment">/* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ |
| </span><span class="kw">let </span>u: f64 = ax - <span class="macro">i!</span>(BP, k <span class="kw">as </span>usize); <span class="comment">/* bp[0]=1.0, bp[1]=1.5 */ |
| </span><span class="kw">let </span>v: f64 = <span class="number">1.0 </span>/ (ax + <span class="macro">i!</span>(BP, k <span class="kw">as </span>usize)); |
| <span class="kw">let </span>ss: f64 = u * v; |
| <span class="kw">let </span>s_h = with_set_low_word(ss, <span class="number">0</span>); |
| |
| <span class="comment">/* t_h=ax+bp[k] High */ |
| </span><span class="kw">let </span>t_h: f64 = with_set_high_word( |
| <span class="number">0.0</span>, |
| ((ix <span class="kw">as </span>u32 >> <span class="number">1</span>) | <span class="number">0x20000000</span>) + <span class="number">0x00080000 </span>+ ((k <span class="kw">as </span>u32) << <span class="number">18</span>), |
| ); |
| <span class="kw">let </span>t_l: f64 = ax - (t_h - <span class="macro">i!</span>(BP, k <span class="kw">as </span>usize)); |
| <span class="kw">let </span>s_l: f64 = v * ((u - s_h * t_h) - s_h * t_l); |
| |
| <span class="comment">/* compute log(ax) */ |
| </span><span class="kw">let </span>s2: f64 = ss * ss; |
| <span class="kw">let </span><span class="kw-2">mut </span>r: f64 = s2 * s2 * (L1 + s2 * (L2 + s2 * (L3 + s2 * (L4 + s2 * (L5 + s2 * L6))))); |
| r += s_l * (s_h + ss); |
| <span class="kw">let </span>s2: f64 = s_h * s_h; |
| <span class="kw">let </span>t_h: f64 = with_set_low_word(<span class="number">3.0 </span>+ s2 + r, <span class="number">0</span>); |
| <span class="kw">let </span>t_l: f64 = r - ((t_h - <span class="number">3.0</span>) - s2); |
| |
| <span class="comment">/* u+v = ss*(1+...) */ |
| </span><span class="kw">let </span>u: f64 = s_h * t_h; |
| <span class="kw">let </span>v: f64 = s_l * t_h + t_l * ss; |
| |
| <span class="comment">/* 2/(3log2)*(ss+...) */ |
| </span><span class="kw">let </span>p_h: f64 = with_set_low_word(u + v, <span class="number">0</span>); |
| <span class="kw">let </span>p_l = v - (p_h - u); |
| <span class="kw">let </span>z_h: f64 = CP_H * p_h; <span class="comment">/* cp_h+cp_l = 2/(3*log2) */ |
| </span><span class="kw">let </span>z_l: f64 = CP_L * p_h + p_l * CP + <span class="macro">i!</span>(DP_L, k <span class="kw">as </span>usize); |
| |
| <span class="comment">/* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */ |
| </span><span class="kw">let </span>t: f64 = n <span class="kw">as </span>f64; |
| t1 = with_set_low_word(((z_h + z_l) + <span class="macro">i!</span>(DP_H, k <span class="kw">as </span>usize)) + t, <span class="number">0</span>); |
| t2 = z_l - (((t1 - t) - <span class="macro">i!</span>(DP_H, k <span class="kw">as </span>usize)) - z_h); |
| } |
| |
| <span class="comment">/* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ |
| </span><span class="kw">let </span>y1: f64 = with_set_low_word(y, <span class="number">0</span>); |
| <span class="kw">let </span>p_l: f64 = (y - y1) * t1 + y * t2; |
| <span class="kw">let </span><span class="kw-2">mut </span>p_h: f64 = y1 * t1; |
| <span class="kw">let </span>z: f64 = p_l + p_h; |
| <span class="kw">let </span><span class="kw-2">mut </span>j: i32 = (z.to_bits() >> <span class="number">32</span>) <span class="kw">as </span>i32; |
| <span class="kw">let </span>i: i32 = z.to_bits() <span class="kw">as </span>i32; |
| <span class="comment">// let (j, i): (i32, i32) = ((z.to_bits() >> 32) as i32, z.to_bits() as i32); |
| |
| </span><span class="kw">if </span>j >= <span class="number">0x40900000 </span>{ |
| <span class="comment">/* z >= 1024 */ |
| </span><span class="kw">if </span>(j - <span class="number">0x40900000</span>) | i != <span class="number">0 </span>{ |
| <span class="comment">/* if z > 1024 */ |
| </span><span class="kw">return </span>s * HUGE * HUGE; <span class="comment">/* overflow */ |
| </span>} |
| |
| <span class="kw">if </span>p_l + OVT > z - p_h { |
| <span class="kw">return </span>s * HUGE * HUGE; <span class="comment">/* overflow */ |
| </span>} |
| } <span class="kw">else if </span>(j & <span class="number">0x7fffffff</span>) >= <span class="number">0x4090cc00 </span>{ |
| <span class="comment">/* z <= -1075 */ |
| // FIXME: instead of abs(j) use unsigned j |
| |
| </span><span class="kw">if </span>(((j <span class="kw">as </span>u32) - <span class="number">0xc090cc00</span>) | (i <span class="kw">as </span>u32)) != <span class="number">0 </span>{ |
| <span class="comment">/* z < -1075 */ |
| </span><span class="kw">return </span>s * TINY * TINY; <span class="comment">/* underflow */ |
| </span>} |
| |
| <span class="kw">if </span>p_l <= z - p_h { |
| <span class="kw">return </span>s * TINY * TINY; <span class="comment">/* underflow */ |
| </span>} |
| } |
| |
| <span class="comment">/* compute 2**(p_h+p_l) */ |
| </span><span class="kw">let </span>i: i32 = j & (<span class="number">0x7fffffff </span><span class="kw">as </span>i32); |
| k = (i >> <span class="number">20</span>) - <span class="number">0x3ff</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>n: i32 = <span class="number">0</span>; |
| |
| <span class="kw">if </span>i > <span class="number">0x3fe00000 </span>{ |
| <span class="comment">/* if |z| > 0.5, set n = [z+0.5] */ |
| </span>n = j + (<span class="number">0x00100000 </span>>> (k + <span class="number">1</span>)); |
| k = ((n & <span class="number">0x7fffffff</span>) >> <span class="number">20</span>) - <span class="number">0x3ff</span>; <span class="comment">/* new k for n */ |
| </span><span class="kw">let </span>t: f64 = with_set_high_word(<span class="number">0.0</span>, (n & !(<span class="number">0x000fffff </span>>> k)) <span class="kw">as </span>u32); |
| n = ((n & <span class="number">0x000fffff</span>) | <span class="number">0x00100000</span>) >> (<span class="number">20 </span>- k); |
| <span class="kw">if </span>j < <span class="number">0 </span>{ |
| n = -n; |
| } |
| p_h -= t; |
| } |
| |
| <span class="kw">let </span>t: f64 = with_set_low_word(p_l + p_h, <span class="number">0</span>); |
| <span class="kw">let </span>u: f64 = t * LG2_H; |
| <span class="kw">let </span>v: f64 = (p_l - (t - p_h)) * LG2 + t * LG2_L; |
| <span class="kw">let </span><span class="kw-2">mut </span>z: f64 = u + v; |
| <span class="kw">let </span>w: f64 = v - (z - u); |
| <span class="kw">let </span>t: f64 = z * z; |
| <span class="kw">let </span>t1: f64 = z - t * (P1 + t * (P2 + t * (P3 + t * (P4 + t * P5)))); |
| <span class="kw">let </span>r: f64 = (z * t1) / (t1 - <span class="number">2.0</span>) - (w + z * w); |
| z = <span class="number">1.0 </span>- (r - z); |
| j = get_high_word(z) <span class="kw">as </span>i32; |
| j += n << <span class="number">20</span>; |
| |
| <span class="kw">if </span>(j >> <span class="number">20</span>) <= <span class="number">0 </span>{ |
| <span class="comment">/* subnormal output */ |
| </span>z = scalbn(z, n); |
| } <span class="kw">else </span>{ |
| z = with_set_high_word(z, j <span class="kw">as </span>u32); |
| } |
| |
| s * z |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">extern crate </span>core; |
| |
| <span class="kw">use </span><span class="self">self</span>::core::f64::consts::{E, PI}; |
| <span class="kw">use </span><span class="self">self</span>::core::f64::{EPSILON, INFINITY, MAX, MIN, MIN_POSITIVE, NAN, NEG_INFINITY}; |
| <span class="kw">use </span><span class="kw">super</span>::pow; |
| |
| <span class="kw">const </span>POS_ZERO: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[<span class="number">0.0</span>]; |
| <span class="kw">const </span>NEG_ZERO: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[-<span class="number">0.0</span>]; |
| <span class="kw">const </span>POS_ONE: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[<span class="number">1.0</span>]; |
| <span class="kw">const </span>NEG_ONE: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[-<span class="number">1.0</span>]; |
| <span class="kw">const </span>POS_FLOATS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[<span class="number">99.0 </span>/ <span class="number">70.0</span>, E, PI]; |
| <span class="kw">const </span>NEG_FLOATS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[-<span class="number">99.0 </span>/ <span class="number">70.0</span>, -E, -PI]; |
| <span class="kw">const </span>POS_SMALL_FLOATS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[(<span class="number">1.0 </span>/ <span class="number">2.0</span>), MIN_POSITIVE, EPSILON]; |
| <span class="kw">const </span>NEG_SMALL_FLOATS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[-(<span class="number">1.0 </span>/ <span class="number">2.0</span>), -MIN_POSITIVE, -EPSILON]; |
| <span class="kw">const </span>POS_EVENS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[<span class="number">2.0</span>, <span class="number">6.0</span>, <span class="number">8.0</span>, <span class="number">10.0</span>, <span class="number">22.0</span>, <span class="number">100.0</span>, MAX]; |
| <span class="kw">const </span>NEG_EVENS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[MIN, -<span class="number">100.0</span>, -<span class="number">22.0</span>, -<span class="number">10.0</span>, -<span class="number">8.0</span>, -<span class="number">6.0</span>, -<span class="number">2.0</span>]; |
| <span class="kw">const </span>POS_ODDS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[<span class="number">3.0</span>, <span class="number">7.0</span>]; |
| <span class="kw">const </span>NEG_ODDS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[-<span class="number">7.0</span>, -<span class="number">3.0</span>]; |
| <span class="kw">const </span>NANS: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[NAN]; |
| <span class="kw">const </span>POS_INF: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[INFINITY]; |
| <span class="kw">const </span>NEG_INF: <span class="kw-2">&</span>[f64] = <span class="kw-2">&</span>[NEG_INFINITY]; |
| |
| <span class="kw">const </span>ALL: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]] = <span class="kw-2">&</span>[ |
| POS_ZERO, |
| NEG_ZERO, |
| NANS, |
| NEG_SMALL_FLOATS, |
| POS_SMALL_FLOATS, |
| NEG_FLOATS, |
| POS_FLOATS, |
| NEG_EVENS, |
| POS_EVENS, |
| NEG_ODDS, |
| POS_ODDS, |
| NEG_INF, |
| POS_INF, |
| NEG_ONE, |
| POS_ONE, |
| ]; |
| <span class="kw">const </span>POS: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]] = <span class="kw-2">&</span>[POS_ZERO, POS_ODDS, POS_ONE, POS_FLOATS, POS_EVENS, POS_INF]; |
| <span class="kw">const </span>NEG: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]] = <span class="kw-2">&</span>[NEG_ZERO, NEG_ODDS, NEG_ONE, NEG_FLOATS, NEG_EVENS, NEG_INF]; |
| |
| <span class="kw">fn </span>pow_test(base: f64, exponent: f64, expected: f64) { |
| <span class="kw">let </span>res = pow(base, exponent); |
| <span class="macro">assert!</span>( |
| <span class="kw">if </span>expected.is_nan() { |
| res.is_nan() |
| } <span class="kw">else </span>{ |
| pow(base, exponent) == expected |
| }, |
| <span class="string">"{} ** {} was {} instead of {}"</span>, |
| base, |
| exponent, |
| res, |
| expected |
| ); |
| } |
| |
| <span class="kw">fn </span>test_sets_as_base(sets: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]], exponent: f64, expected: f64) { |
| sets.iter() |
| .for_each(|s| s.iter().for_each(|val| pow_test(<span class="kw-2">*</span>val, exponent, expected))); |
| } |
| |
| <span class="kw">fn </span>test_sets_as_exponent(base: f64, sets: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]], expected: f64) { |
| sets.iter() |
| .for_each(|s| s.iter().for_each(|val| pow_test(base, <span class="kw-2">*</span>val, expected))); |
| } |
| |
| <span class="kw">fn </span>test_sets(sets: <span class="kw-2">&</span>[<span class="kw-2">&</span>[f64]], computed: <span class="kw-2">&</span><span class="kw">dyn </span>Fn(f64) -> f64, expected: <span class="kw-2">&</span><span class="kw">dyn </span>Fn(f64) -> f64) { |
| sets.iter().for_each(|s| { |
| s.iter().for_each(|val| { |
| <span class="kw">let </span>exp = expected(<span class="kw-2">*</span>val); |
| <span class="kw">let </span>res = computed(<span class="kw-2">*</span>val); |
| |
| <span class="attribute">#[cfg(all(target_arch = <span class="string">"x86"</span>, not(target_feature = <span class="string">"sse2"</span>)))] |
| </span><span class="kw">let </span>exp = <span class="macro">force_eval!</span>(exp); |
| <span class="attribute">#[cfg(all(target_arch = <span class="string">"x86"</span>, not(target_feature = <span class="string">"sse2"</span>)))] |
| </span><span class="kw">let </span>res = <span class="macro">force_eval!</span>(res); |
| <span class="macro">assert!</span>( |
| <span class="kw">if </span>exp.is_nan() { |
| res.is_nan() |
| } <span class="kw">else </span>{ |
| exp == res |
| }, |
| <span class="string">"test for {} was {} instead of {}"</span>, |
| val, |
| res, |
| exp |
| ); |
| }) |
| }); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>zero_as_exponent() { |
| test_sets_as_base(ALL, <span class="number">0.0</span>, <span class="number">1.0</span>); |
| test_sets_as_base(ALL, -<span class="number">0.0</span>, <span class="number">1.0</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>one_as_base() { |
| test_sets_as_exponent(<span class="number">1.0</span>, ALL, <span class="number">1.0</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>nan_inputs() { |
| <span class="comment">// NAN as the base: |
| // (NAN ^ anything *but 0* should be NAN) |
| </span>test_sets_as_exponent(NAN, <span class="kw-2">&</span>ALL[<span class="number">2</span>..], NAN); |
| |
| <span class="comment">// NAN as the exponent: |
| // (anything *but 1* ^ NAN should be NAN) |
| </span>test_sets_as_base(<span class="kw-2">&</span>ALL[..(ALL.len() - <span class="number">2</span>)], NAN, NAN); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>infinity_as_base() { |
| <span class="comment">// Positive Infinity as the base: |
| // (+Infinity ^ positive anything but 0 and NAN should be +Infinity) |
| </span>test_sets_as_exponent(INFINITY, <span class="kw-2">&</span>POS[<span class="number">1</span>..], INFINITY); |
| |
| <span class="comment">// (+Infinity ^ negative anything except 0 and NAN should be 0.0) |
| </span>test_sets_as_exponent(INFINITY, <span class="kw-2">&</span>NEG[<span class="number">1</span>..], <span class="number">0.0</span>); |
| |
| <span class="comment">// Negative Infinity as the base: |
| // (-Infinity ^ positive odd ints should be -Infinity) |
| </span>test_sets_as_exponent(NEG_INFINITY, <span class="kw-2">&</span>[POS_ODDS], NEG_INFINITY); |
| |
| <span class="comment">// (-Infinity ^ anything but odd ints should be == -0 ^ (-anything)) |
| // We can lump in pos/neg odd ints here because they don't seem to |
| // cause panics (div by zero) in release mode (I think). |
| </span>test_sets(ALL, <span class="kw-2">&</span>|v: f64| pow(NEG_INFINITY, v), <span class="kw-2">&</span>|v: f64| pow(-<span class="number">0.0</span>, -v)); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>infinity_as_exponent() { |
| <span class="comment">// Positive/Negative base greater than 1: |
| // (pos/neg > 1 ^ Infinity should be Infinity - note this excludes NAN as the base) |
| </span>test_sets_as_base(<span class="kw-2">&</span>ALL[<span class="number">5</span>..(ALL.len() - <span class="number">2</span>)], INFINITY, INFINITY); |
| |
| <span class="comment">// (pos/neg > 1 ^ -Infinity should be 0.0) |
| </span>test_sets_as_base(<span class="kw-2">&</span>ALL[<span class="number">5</span>..ALL.len() - <span class="number">2</span>], NEG_INFINITY, <span class="number">0.0</span>); |
| |
| <span class="comment">// Positive/Negative base less than 1: |
| </span><span class="kw">let </span>base_below_one = <span class="kw-2">&</span>[POS_ZERO, NEG_ZERO, NEG_SMALL_FLOATS, POS_SMALL_FLOATS]; |
| |
| <span class="comment">// (pos/neg < 1 ^ Infinity should be 0.0 - this also excludes NAN as the base) |
| </span>test_sets_as_base(base_below_one, INFINITY, <span class="number">0.0</span>); |
| |
| <span class="comment">// (pos/neg < 1 ^ -Infinity should be Infinity) |
| </span>test_sets_as_base(base_below_one, NEG_INFINITY, INFINITY); |
| |
| <span class="comment">// Positive/Negative 1 as the base: |
| // (pos/neg 1 ^ Infinity should be 1) |
| </span>test_sets_as_base(<span class="kw-2">&</span>[NEG_ONE, POS_ONE], INFINITY, <span class="number">1.0</span>); |
| |
| <span class="comment">// (pos/neg 1 ^ -Infinity should be 1) |
| </span>test_sets_as_base(<span class="kw-2">&</span>[NEG_ONE, POS_ONE], NEG_INFINITY, <span class="number">1.0</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>zero_as_base() { |
| <span class="comment">// Positive Zero as the base: |
| // (+0 ^ anything positive but 0 and NAN should be +0) |
| </span>test_sets_as_exponent(<span class="number">0.0</span>, <span class="kw-2">&</span>POS[<span class="number">1</span>..], <span class="number">0.0</span>); |
| |
| <span class="comment">// (+0 ^ anything negative but 0 and NAN should be Infinity) |
| // (this should panic because we're dividing by zero) |
| </span>test_sets_as_exponent(<span class="number">0.0</span>, <span class="kw-2">&</span>NEG[<span class="number">1</span>..], INFINITY); |
| |
| <span class="comment">// Negative Zero as the base: |
| // (-0 ^ anything positive but 0, NAN, and odd ints should be +0) |
| </span>test_sets_as_exponent(-<span class="number">0.0</span>, <span class="kw-2">&</span>POS[<span class="number">3</span>..], <span class="number">0.0</span>); |
| |
| <span class="comment">// (-0 ^ anything negative but 0, NAN, and odd ints should be Infinity) |
| // (should panic because of divide by zero) |
| </span>test_sets_as_exponent(-<span class="number">0.0</span>, <span class="kw-2">&</span>NEG[<span class="number">3</span>..], INFINITY); |
| |
| <span class="comment">// (-0 ^ positive odd ints should be -0) |
| </span>test_sets_as_exponent(-<span class="number">0.0</span>, <span class="kw-2">&</span>[POS_ODDS], -<span class="number">0.0</span>); |
| |
| <span class="comment">// (-0 ^ negative odd ints should be -Infinity) |
| // (should panic because of divide by zero) |
| </span>test_sets_as_exponent(-<span class="number">0.0</span>, <span class="kw-2">&</span>[NEG_ODDS], NEG_INFINITY); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>special_cases() { |
| <span class="comment">// One as the exponent: |
| // (anything ^ 1 should be anything - i.e. the base) |
| </span>test_sets(ALL, <span class="kw-2">&</span>|v: f64| pow(v, <span class="number">1.0</span>), <span class="kw-2">&</span>|v: f64| v); |
| |
| <span class="comment">// Negative One as the exponent: |
| // (anything ^ -1 should be 1/anything) |
| </span>test_sets(ALL, <span class="kw-2">&</span>|v: f64| pow(v, -<span class="number">1.0</span>), <span class="kw-2">&</span>|v: f64| <span class="number">1.0 </span>/ v); |
| |
| <span class="comment">// Factoring -1 out: |
| // (negative anything ^ integer should be (-1 ^ integer) * (positive anything ^ integer)) |
| </span>(<span class="kw-2">&</span>[POS_ZERO, NEG_ZERO, POS_ONE, NEG_ONE, POS_EVENS, NEG_EVENS]) |
| .iter() |
| .for_each(|int_set| { |
| int_set.iter().for_each(|int| { |
| test_sets(ALL, <span class="kw-2">&</span>|v: f64| pow(-v, <span class="kw-2">*</span>int), <span class="kw-2">&</span>|v: f64| { |
| pow(-<span class="number">1.0</span>, <span class="kw-2">*</span>int) * pow(v, <span class="kw-2">*</span>int) |
| }); |
| }) |
| }); |
| |
| <span class="comment">// Negative base (imaginary results): |
| // (-anything except 0 and Infinity ^ non-integer should be NAN) |
| </span>(<span class="kw-2">&</span>NEG[<span class="number">1</span>..(NEG.len() - <span class="number">1</span>)]).iter().for_each(|set| { |
| set.iter().for_each(|val| { |
| test_sets(<span class="kw-2">&</span>ALL[<span class="number">3</span>..<span class="number">7</span>], <span class="kw-2">&</span>|v: f64| pow(<span class="kw-2">*</span>val, v), <span class="kw-2">&</span>|<span class="kw">_</span>| NAN); |
| }) |
| }); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>normal_cases() { |
| <span class="macro">assert_eq!</span>(pow(<span class="number">2.0</span>, <span class="number">20.0</span>), (<span class="number">1 </span><< <span class="number">20</span>) <span class="kw">as </span>f64); |
| <span class="macro">assert_eq!</span>(pow(-<span class="number">1.0</span>, <span class="number">9.0</span>), -<span class="number">1.0</span>); |
| <span class="macro">assert!</span>(pow(-<span class="number">1.0</span>, <span class="number">2.2</span>).is_nan()); |
| <span class="macro">assert!</span>(pow(-<span class="number">1.0</span>, -<span class="number">1.14</span>).is_nan()); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="libm" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
