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Diffstat (limited to 'library/compiler-builtins/libm/src/math/pow.rs')
| -rw-r--r-- | library/compiler-builtins/libm/src/math/pow.rs | 607 |
1 files changed, 607 insertions, 0 deletions
diff --git a/library/compiler-builtins/libm/src/math/pow.rs b/library/compiler-builtins/libm/src/math/pow.rs new file mode 100644 index 00000000000..80b2a24999c --- /dev/null +++ b/library/compiler-builtins/libm/src/math/pow.rs @@ -0,0 +1,607 @@ +/* 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 multi-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. +// +use super::{fabs, get_high_word, scalbn, sqrt, with_set_high_word, with_set_low_word}; + +const BP: [f64; 2] = [1.0, 1.5]; +const DP_H: [f64; 2] = [0.0, 5.84962487220764160156e-01]; /* 0x3fe2b803_40000000 */ +const DP_L: [f64; 2] = [0.0, 1.35003920212974897128e-08]; /* 0x3E4CFDEB, 0x43CFD006 */ +const TWO53: f64 = 9007199254740992.0; /* 0x43400000_00000000 */ +const HUGE: f64 = 1.0e300; +const TINY: f64 = 1.0e-300; + +// poly coefs for (3/2)*(log(x)-2s-2/3*s**3: +const L1: f64 = 5.99999999999994648725e-01; /* 0x3fe33333_33333303 */ +const L2: f64 = 4.28571428578550184252e-01; /* 0x3fdb6db6_db6fabff */ +const L3: f64 = 3.33333329818377432918e-01; /* 0x3fd55555_518f264d */ +const L4: f64 = 2.72728123808534006489e-01; /* 0x3fd17460_a91d4101 */ +const L5: f64 = 2.30660745775561754067e-01; /* 0x3fcd864a_93c9db65 */ +const L6: f64 = 2.06975017800338417784e-01; /* 0x3fca7e28_4a454eef */ +const P1: f64 = 1.66666666666666019037e-01; /* 0x3fc55555_5555553e */ +const P2: f64 = -2.77777777770155933842e-03; /* 0xbf66c16c_16bebd93 */ +const P3: f64 = 6.61375632143793436117e-05; /* 0x3f11566a_af25de2c */ +const P4: f64 = -1.65339022054652515390e-06; /* 0xbebbbd41_c5d26bf1 */ +const P5: f64 = 4.13813679705723846039e-08; /* 0x3e663769_72bea4d0 */ +const LG2: f64 = 6.93147180559945286227e-01; /* 0x3fe62e42_fefa39ef */ +const LG2_H: f64 = 6.93147182464599609375e-01; /* 0x3fe62e43_00000000 */ +const LG2_L: f64 = -1.90465429995776804525e-09; /* 0xbe205c61_0ca86c39 */ +const OVT: f64 = 8.0085662595372944372e-017; /* -(1024-log2(ovfl+.5ulp)) */ +const CP: f64 = 9.61796693925975554329e-01; /* 0x3feec709_dc3a03fd =2/(3ln2) */ +const CP_H: f64 = 9.61796700954437255859e-01; /* 0x3feec709_e0000000 =(float)cp */ +const CP_L: f64 = -7.02846165095275826516e-09; /* 0xbe3e2fe0_145b01f5 =tail of cp_h*/ +const IVLN2: f64 = 1.44269504088896338700e+00; /* 0x3ff71547_652b82fe =1/ln2 */ +const IVLN2_H: f64 = 1.44269502162933349609e+00; /* 0x3ff71547_60000000 =24b 1/ln2*/ +const IVLN2_L: f64 = 1.92596299112661746887e-08; /* 0x3e54ae0b_f85ddf44 =1/ln2 tail*/ + +/// Returns `x` to the power of `y` (f64). +#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] +pub fn pow(x: f64, y: f64) -> f64 { + let t1: f64; + let t2: f64; + + let (hx, lx): (i32, u32) = ((x.to_bits() >> 32) as i32, x.to_bits() as u32); + let (hy, ly): (i32, u32) = ((y.to_bits() >> 32) as i32, y.to_bits() as u32); + + let mut ix: i32 = hx & 0x7fffffff_i32; + let iy: i32 = hy & 0x7fffffff_i32; + + /* x**0 = 1, even if x is NaN */ + if ((iy as u32) | ly) == 0 { + return 1.0; + } + + /* 1**y = 1, even if y is NaN */ + if hx == 0x3ff00000 && lx == 0 { + return 1.0; + } + + /* NaN if either arg is NaN */ + if ix > 0x7ff00000 + || (ix == 0x7ff00000 && lx != 0) + || iy > 0x7ff00000 + || (iy == 0x7ff00000 && ly != 0) + { + return x + y; + } + + /* 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 + */ + let mut yisint: i32 = 0; + let mut k: i32; + let mut j: i32; + if hx < 0 { + if iy >= 0x43400000 { + yisint = 2; /* even integer y */ + } else if iy >= 0x3ff00000 { + k = (iy >> 20) - 0x3ff; /* exponent */ + + if k > 20 { + j = (ly >> (52 - k)) as i32; + + if (j << (52 - k)) == (ly as i32) { + yisint = 2 - (j & 1); + } + } else if ly == 0 { + j = iy >> (20 - k); + + if (j << (20 - k)) == iy { + yisint = 2 - (j & 1); + } + } + } + } + + if ly == 0 { + /* special value of y */ + if iy == 0x7ff00000 { + /* y is +-inf */ + + return if ((ix - 0x3ff00000) | (lx as i32)) == 0 { + /* (-1)**+-inf is 1 */ + 1.0 + } else if ix >= 0x3ff00000 { + /* (|x|>1)**+-inf = inf,0 */ + if hy >= 0 { y } else { 0.0 } + } else { + /* (|x|<1)**+-inf = 0,inf */ + if hy >= 0 { 0.0 } else { -y } + }; + } + + if iy == 0x3ff00000 { + /* y is +-1 */ + return if hy >= 0 { x } else { 1.0 / x }; + } + + if hy == 0x40000000 { + /* y is 2 */ + return x * x; + } + + if hy == 0x3fe00000 { + /* y is 0.5 */ + if hx >= 0 { + /* x >= +0 */ + return sqrt(x); + } + } + } + + let mut ax: f64 = fabs(x); + if lx == 0 { + /* special value of x */ + if ix == 0x7ff00000 || ix == 0 || ix == 0x3ff00000 { + /* x is +-0,+-inf,+-1 */ + let mut z: f64 = ax; + + if hy < 0 { + /* z = (1/|x|) */ + z = 1.0 / z; + } + + if hx < 0 { + if ((ix - 0x3ff00000) | yisint) == 0 { + z = (z - z) / (z - z); /* (-1)**non-int is NaN */ + } else if yisint == 1 { + z = -z; /* (x<0)**odd = -(|x|**odd) */ + } + } + + return z; + } + } + + let mut s: f64 = 1.0; /* sign of result */ + if hx < 0 { + if yisint == 0 { + /* (x<0)**(non-int) is NaN */ + return (x - x) / (x - x); + } + + if yisint == 1 { + /* (x<0)**(odd int) */ + s = -1.0; + } + } + + /* |y| is HUGE */ + if iy > 0x41e00000 { + /* if |y| > 2**31 */ + if iy > 0x43f00000 { + /* if |y| > 2**64, must o/uflow */ + if ix <= 0x3fefffff { + return if hy < 0 { HUGE * HUGE } else { TINY * TINY }; + } + + if ix >= 0x3ff00000 { + return if hy > 0 { HUGE * HUGE } else { TINY * TINY }; + } + } + + /* over/underflow if x is not close to one */ + if ix < 0x3fefffff { + return if hy < 0 { s * HUGE * HUGE } else { s * TINY * TINY }; + } + if ix > 0x3ff00000 { + return if hy > 0 { s * HUGE * HUGE } else { s * TINY * TINY }; + } + + /* now |1-x| is TINY <= 2**-20, suffice to compute + log(x) by x-x^2/2+x^3/3-x^4/4 */ + let t: f64 = ax - 1.0; /* t has 20 trailing zeros */ + let w: f64 = (t * t) * (0.5 - t * (0.3333333333333333333333 - t * 0.25)); + let u: f64 = IVLN2_H * t; /* ivln2_h has 21 sig. bits */ + let v: f64 = t * IVLN2_L - w * IVLN2; + t1 = with_set_low_word(u + v, 0); + t2 = v - (t1 - u); + } else { + // double ss,s2,s_h,s_l,t_h,t_l; + let mut n: i32 = 0; + + if ix < 0x00100000 { + /* take care subnormal number */ + ax *= TWO53; + n -= 53; + ix = get_high_word(ax) as i32; + } + + n += (ix >> 20) - 0x3ff; + j = ix & 0x000fffff; + + /* determine interval */ + let k: i32; + ix = j | 0x3ff00000; /* normalize ix */ + if j <= 0x3988E { + /* |x|<sqrt(3/2) */ + k = 0; + } else if j < 0xBB67A { + /* |x|<sqrt(3) */ + k = 1; + } else { + k = 0; + n += 1; + ix -= 0x00100000; + } + ax = with_set_high_word(ax, ix as u32); + + /* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ + let u: f64 = ax - i!(BP, k as usize); /* bp[0]=1.0, bp[1]=1.5 */ + let v: f64 = 1.0 / (ax + i!(BP, k as usize)); + let ss: f64 = u * v; + let s_h = with_set_low_word(ss, 0); + + /* t_h=ax+bp[k] High */ + let t_h: f64 = with_set_high_word( + 0.0, + ((ix as u32 >> 1) | 0x20000000) + 0x00080000 + ((k as u32) << 18), + ); + let t_l: f64 = ax - (t_h - i!(BP, k as usize)); + let s_l: f64 = v * ((u - s_h * t_h) - s_h * t_l); + + /* compute log(ax) */ + let s2: f64 = ss * ss; + let mut r: f64 = s2 * s2 * (L1 + s2 * (L2 + s2 * (L3 + s2 * (L4 + s2 * (L5 + s2 * L6))))); + r += s_l * (s_h + ss); + let s2: f64 = s_h * s_h; + let t_h: f64 = with_set_low_word(3.0 + s2 + r, 0); + let t_l: f64 = r - ((t_h - 3.0) - s2); + + /* u+v = ss*(1+...) */ + let u: f64 = s_h * t_h; + let v: f64 = s_l * t_h + t_l * ss; + + /* 2/(3log2)*(ss+...) */ + let p_h: f64 = with_set_low_word(u + v, 0); + let p_l = v - (p_h - u); + let z_h: f64 = CP_H * p_h; /* cp_h+cp_l = 2/(3*log2) */ + let z_l: f64 = CP_L * p_h + p_l * CP + i!(DP_L, k as usize); + + /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */ + let t: f64 = n as f64; + t1 = with_set_low_word(((z_h + z_l) + i!(DP_H, k as usize)) + t, 0); + t2 = z_l - (((t1 - t) - i!(DP_H, k as usize)) - z_h); + } + + /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ + let y1: f64 = with_set_low_word(y, 0); + let p_l: f64 = (y - y1) * t1 + y * t2; + let mut p_h: f64 = y1 * t1; + let z: f64 = p_l + p_h; + let mut j: i32 = (z.to_bits() >> 32) as i32; + let i: i32 = z.to_bits() as i32; + // let (j, i): (i32, i32) = ((z.to_bits() >> 32) as i32, z.to_bits() as i32); + + if j >= 0x40900000 { + /* z >= 1024 */ + if (j - 0x40900000) | i != 0 { + /* if z > 1024 */ + return s * HUGE * HUGE; /* overflow */ + } + + if p_l + OVT > z - p_h { + return s * HUGE * HUGE; /* overflow */ + } + } else if (j & 0x7fffffff) >= 0x4090cc00 { + /* z <= -1075 */ + // FIXME: instead of abs(j) use unsigned j + + if (((j as u32) - 0xc090cc00) | (i as u32)) != 0 { + /* z < -1075 */ + return s * TINY * TINY; /* underflow */ + } + + if p_l <= z - p_h { + return s * TINY * TINY; /* underflow */ + } + } + + /* compute 2**(p_h+p_l) */ + let i: i32 = j & 0x7fffffff_i32; + k = (i >> 20) - 0x3ff; + let mut n: i32 = 0; + + if i > 0x3fe00000 { + /* if |z| > 0.5, set n = [z+0.5] */ + n = j + (0x00100000 >> (k + 1)); + k = ((n & 0x7fffffff) >> 20) - 0x3ff; /* new k for n */ + let t: f64 = with_set_high_word(0.0, (n & !(0x000fffff >> k)) as u32); + n = ((n & 0x000fffff) | 0x00100000) >> (20 - k); + if j < 0 { + n = -n; + } + p_h -= t; + } + + let t: f64 = with_set_low_word(p_l + p_h, 0); + let u: f64 = t * LG2_H; + let v: f64 = (p_l - (t - p_h)) * LG2 + t * LG2_L; + let mut z: f64 = u + v; + let w: f64 = v - (z - u); + let t: f64 = z * z; + let t1: f64 = z - t * (P1 + t * (P2 + t * (P3 + t * (P4 + t * P5)))); + let r: f64 = (z * t1) / (t1 - 2.0) - (w + z * w); + z = 1.0 - (r - z); + j = get_high_word(z) as i32; + j += n << 20; + + if (j >> 20) <= 0 { + /* subnormal output */ + z = scalbn(z, n); + } else { + z = with_set_high_word(z, j as u32); + } + + s * z +} + +#[cfg(test)] +mod tests { + extern crate core; + + use self::core::f64::consts::{E, PI}; + use super::pow; + + const POS_ZERO: &[f64] = &[0.0]; + const NEG_ZERO: &[f64] = &[-0.0]; + const POS_ONE: &[f64] = &[1.0]; + const NEG_ONE: &[f64] = &[-1.0]; + const POS_FLOATS: &[f64] = &[99.0 / 70.0, E, PI]; + const NEG_FLOATS: &[f64] = &[-99.0 / 70.0, -E, -PI]; + const POS_SMALL_FLOATS: &[f64] = &[(1.0 / 2.0), f64::MIN_POSITIVE, f64::EPSILON]; + const NEG_SMALL_FLOATS: &[f64] = &[-(1.0 / 2.0), -f64::MIN_POSITIVE, -f64::EPSILON]; + const POS_EVENS: &[f64] = &[2.0, 6.0, 8.0, 10.0, 22.0, 100.0, f64::MAX]; + const NEG_EVENS: &[f64] = &[f64::MIN, -100.0, -22.0, -10.0, -8.0, -6.0, -2.0]; + const POS_ODDS: &[f64] = &[3.0, 7.0]; + const NEG_ODDS: &[f64] = &[-7.0, -3.0]; + const NANS: &[f64] = &[f64::NAN]; + const POS_INF: &[f64] = &[f64::INFINITY]; + const NEG_INF: &[f64] = &[f64::NEG_INFINITY]; + + const ALL: &[&[f64]] = &[ + 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, + ]; + const POS: &[&[f64]] = &[POS_ZERO, POS_ODDS, POS_ONE, POS_FLOATS, POS_EVENS, POS_INF]; + const NEG: &[&[f64]] = &[NEG_ZERO, NEG_ODDS, NEG_ONE, NEG_FLOATS, NEG_EVENS, NEG_INF]; + + fn pow_test(base: f64, exponent: f64, expected: f64) { + let res = pow(base, exponent); + assert!( + if expected.is_nan() { res.is_nan() } else { pow(base, exponent) == expected }, + "{} ** {} was {} instead of {}", + base, + exponent, + res, + expected + ); + } + + fn test_sets_as_base(sets: &[&[f64]], exponent: f64, expected: f64) { + sets.iter().for_each(|s| s.iter().for_each(|val| pow_test(*val, exponent, expected))); + } + + fn test_sets_as_exponent(base: f64, sets: &[&[f64]], expected: f64) { + sets.iter().for_each(|s| s.iter().for_each(|val| pow_test(base, *val, expected))); + } + + fn test_sets(sets: &[&[f64]], computed: &dyn Fn(f64) -> f64, expected: &dyn Fn(f64) -> f64) { + sets.iter().for_each(|s| { + s.iter().for_each(|val| { + let exp = expected(*val); + let res = computed(*val); + + #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] + let exp = force_eval!(exp); + #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] + let res = force_eval!(res); + assert!( + if exp.is_nan() { res.is_nan() } else { exp == res }, + "test for {} was {} instead of {}", + val, + res, + exp + ); + }) + }); + } + + #[test] + fn zero_as_exponent() { + test_sets_as_base(ALL, 0.0, 1.0); + test_sets_as_base(ALL, -0.0, 1.0); + } + + #[test] + fn one_as_base() { + test_sets_as_exponent(1.0, ALL, 1.0); + } + + #[test] + fn nan_inputs() { + // NAN as the base: + // (f64::NAN ^ anything *but 0* should be f64::NAN) + test_sets_as_exponent(f64::NAN, &ALL[2..], f64::NAN); + + // f64::NAN as the exponent: + // (anything *but 1* ^ f64::NAN should be f64::NAN) + test_sets_as_base(&ALL[..(ALL.len() - 2)], f64::NAN, f64::NAN); + } + + #[test] + fn infinity_as_base() { + // Positive Infinity as the base: + // (+Infinity ^ positive anything but 0 and f64::NAN should be +Infinity) + test_sets_as_exponent(f64::INFINITY, &POS[1..], f64::INFINITY); + + // (+Infinity ^ negative anything except 0 and f64::NAN should be 0.0) + test_sets_as_exponent(f64::INFINITY, &NEG[1..], 0.0); + + // Negative Infinity as the base: + // (-Infinity ^ positive odd ints should be -Infinity) + test_sets_as_exponent(f64::NEG_INFINITY, &[POS_ODDS], f64::NEG_INFINITY); + + // (-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). + test_sets(ALL, &|v: f64| pow(f64::NEG_INFINITY, v), &|v: f64| pow(-0.0, -v)); + } + + #[test] + fn infinity_as_exponent() { + // Positive/Negative base greater than 1: + // (pos/neg > 1 ^ Infinity should be Infinity - note this excludes f64::NAN as the base) + test_sets_as_base(&ALL[5..(ALL.len() - 2)], f64::INFINITY, f64::INFINITY); + + // (pos/neg > 1 ^ -Infinity should be 0.0) + test_sets_as_base(&ALL[5..ALL.len() - 2], f64::NEG_INFINITY, 0.0); + + // Positive/Negative base less than 1: + let base_below_one = &[POS_ZERO, NEG_ZERO, NEG_SMALL_FLOATS, POS_SMALL_FLOATS]; + + // (pos/neg < 1 ^ Infinity should be 0.0 - this also excludes f64::NAN as the base) + test_sets_as_base(base_below_one, f64::INFINITY, 0.0); + + // (pos/neg < 1 ^ -Infinity should be Infinity) + test_sets_as_base(base_below_one, f64::NEG_INFINITY, f64::INFINITY); + + // Positive/Negative 1 as the base: + // (pos/neg 1 ^ Infinity should be 1) + test_sets_as_base(&[NEG_ONE, POS_ONE], f64::INFINITY, 1.0); + + // (pos/neg 1 ^ -Infinity should be 1) + test_sets_as_base(&[NEG_ONE, POS_ONE], f64::NEG_INFINITY, 1.0); + } + + #[test] + fn zero_as_base() { + // Positive Zero as the base: + // (+0 ^ anything positive but 0 and f64::NAN should be +0) + test_sets_as_exponent(0.0, &POS[1..], 0.0); + + // (+0 ^ anything negative but 0 and f64::NAN should be Infinity) + // (this should panic because we're dividing by zero) + test_sets_as_exponent(0.0, &NEG[1..], f64::INFINITY); + + // Negative Zero as the base: + // (-0 ^ anything positive but 0, f64::NAN, and odd ints should be +0) + test_sets_as_exponent(-0.0, &POS[3..], 0.0); + + // (-0 ^ anything negative but 0, f64::NAN, and odd ints should be Infinity) + // (should panic because of divide by zero) + test_sets_as_exponent(-0.0, &NEG[3..], f64::INFINITY); + + // (-0 ^ positive odd ints should be -0) + test_sets_as_exponent(-0.0, &[POS_ODDS], -0.0); + + // (-0 ^ negative odd ints should be -Infinity) + // (should panic because of divide by zero) + test_sets_as_exponent(-0.0, &[NEG_ODDS], f64::NEG_INFINITY); + } + + #[test] + fn special_cases() { + // One as the exponent: + // (anything ^ 1 should be anything - i.e. the base) + test_sets(ALL, &|v: f64| pow(v, 1.0), &|v: f64| v); + + // Negative One as the exponent: + // (anything ^ -1 should be 1/anything) + test_sets(ALL, &|v: f64| pow(v, -1.0), &|v: f64| 1.0 / v); + + // Factoring -1 out: + // (negative anything ^ integer should be (-1 ^ integer) * (positive anything ^ integer)) + [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, &|v: f64| pow(-v, *int), &|v: f64| pow(-1.0, *int) * pow(v, *int)); + }) + }); + + // Negative base (imaginary results): + // (-anything except 0 and Infinity ^ non-integer should be NAN) + NEG[1..(NEG.len() - 1)].iter().for_each(|set| { + set.iter().for_each(|val| { + test_sets(&ALL[3..7], &|v: f64| pow(*val, v), &|_| f64::NAN); + }) + }); + } + + #[test] + fn normal_cases() { + assert_eq!(pow(2.0, 20.0), (1 << 20) as f64); + assert_eq!(pow(-1.0, 9.0), -1.0); + assert!(pow(-1.0, 2.2).is_nan()); + assert!(pow(-1.0, -1.14).is_nan()); + } +} |