zig/lib/std/math/acos.zig

627 lines
29 KiB
Zig

// Ported from musl, which is licensed under the MIT license:
// https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
//
// https://git.musl-libc.org/cgit/musl/tree/src/math/acosf.c
// https://git.musl-libc.org/cgit/musl/tree/src/math/acos.c
// https://git.musl-libc.org/cgit/musl/tree/src/math/acosl.c
//
// Ported from ARM-software, which is licensed under the MIT license:
// https://github.com/ARM-software/optimized-routines/blob/master/LICENSE
//
// https://github.com/ARM-software/optimized-routines/blob/master/math/aarch64/advsimd/acosf.c
// https://github.com/ARM-software/optimized-routines/blob/master/math/aarch64/advsimd/acos.c
const std = @import("../std.zig");
const math = std.math;
const testing = std.testing;
const builtin = @import("builtin");
const native_endian = builtin.cpu.arch.endian();
/// Returns the arc-cosine of x.
///
/// Special cases:
/// - acos(x) = nan if x < -1 or x > 1
pub fn acos(x: anytype) @TypeOf(x) {
const T = @TypeOf(x);
switch (@typeInfo(T)) {
.float => |info| switch (info.bits) {
16 => return acosBinary16(x),
32 => return acosBinary32(x),
64 => return acosBinary64(x),
80 => return acosExtended80(x),
128 => return acosBinary128(x),
else => comptime unreachable,
},
.vector => |info| switch (info.child) {
f32 => return acosBinary32Vec(info.len, x),
f64 => return acosBinary64Vec(info.len, x),
else => @compileError("unimplemented"),
},
else => comptime unreachable,
}
}
fn approxBinary16(z: f32) f32 {
const S0: f32 = 1.0000001e0;
const S1: f32 = 1.6664918e-1;
const S2: f32 = 7.55022e-2;
const S3: f32 = 3.9513987e-2;
const S4: f32 = 5.0883885e-2;
return S0 + z * (S1 + z * (S2 + z * (S3 + z * S4)));
}
fn acosBinary16(x: f16) f16 {
const pio2: f32 = math.pi / 2.0;
const hx: u16 = @bitCast(x);
const ix: u16 = hx & 0x7fff;
// |x| >= 1 or nan
if (ix >= 0x3c00) {
if (ix == 0x3c00) {
if (hx >> 15 != 0) {
return @floatCast(2.0 * pio2 + 0x1p-120);
}
return 0.0;
}
return 0.0 / (x - x);
}
const xf: f32 = @floatCast(x);
// |x| < 0.5
if (ix < 0x3800) {
return @floatCast(pio2 - xf * approxBinary16(xf * xf));
}
// x < -0.5
if (hx >> 15 != 0) {
const z = (1.0 + xf) * 0.5;
const s = @sqrt(z);
const w = approxBinary16(z) * s;
return @floatCast(2.0 * (pio2 - w));
}
// x > 0.5
const z = (1.0 - xf) * 0.5;
const s = @sqrt(z);
const w = approxBinary16(z) * s;
return @floatCast(2.0 * w);
}
fn rationalApproxBinary32(z: f32) f32 {
const pS0: f32 = 1.6666586697e-01;
const pS1: f32 = -4.2743422091e-02;
const pS2: f32 = -8.6563630030e-03;
const qS1: f32 = -7.0662963390e-01;
// f64 is used instead of f32 to avoid
// a vectorization on x86_64. The vectorization
// causes extra floating point execeptions
// that are prohibited by libc-test.
const p: f64 = @as(f64, @floatCast(z)) * (pS0 + z * (pS1 + z * pS2));
const q: f64 = 1.0 + z * qS1;
return @floatCast(p / q);
}
fn acosBinary32(x: f32) f32 {
const pio2_hi: f32 = 1.5707962513e+00;
const pio2_lo: f32 = 7.5497894159e-08;
const hx: u32 = @bitCast(x);
const ix: u32 = hx & 0x7fff_ffff;
// |x| >= 1 or nan
if (ix >= 0x3f800000) {
if (ix == 0x3f800000) {
if (hx >> 31 != 0) {
return 2.0 * pio2_hi + 0x1.0p-120;
}
return 0.0;
}
return 0.0 / (x - x);
}
// |x| < 0.5
if (ix < 0x3f00_0000) {
// |x| < 2^(-26)
if (ix <= 0x3280_0000) {
return pio2_hi + 0x1.0p-120;
}
return pio2_hi - (x - (pio2_lo - x * rationalApproxBinary32(x * x)));
}
// x < -0.5
if (hx >> 31 != 0) {
const z = (1 + x) * 0.5;
const s = @sqrt(z);
const w = rationalApproxBinary32(z) * s - pio2_lo;
return 2.0 * (pio2_hi - (s + w));
}
// x > 0.5
const z = (1.0 - x) * 0.5;
const s = @sqrt(z);
const hs: u32 = @bitCast(s);
const df: f32 = @bitCast(hs & 0xffff_f000);
const c = (z - df * df) / (s + df);
const w = rationalApproxBinary32(z) * s + c;
return 2.0 * (df + w);
}
fn rationalApproxBinary64(z: f64) f64 {
const pS0: f64 = 1.66666666666666657415e-01;
const pS1: f64 = -3.25565818622400915405e-01;
const pS2: f64 = 2.01212532134862925881e-01;
const pS3: f64 = -4.00555345006794114027e-02;
const pS4: f64 = 7.91534994289814532176e-04;
const pS5: f64 = 3.47933107596021167570e-05;
const qS1: f64 = -2.40339491173441421878e+00;
const qS2: f64 = 2.02094576023350569471e+00;
const qS3: f64 = -6.88283971605453293030e-01;
const qS4: f64 = 7.70381505559019352791e-02;
const p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
const q = 1.0 + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
return p / q;
}
fn acosBinary64(x: f64) f64 {
const pio2_hi: f64 = 1.57079632679489655800e+00;
const pio2_lo: f64 = 6.12323399573676603587e-17;
const hx: u32 = @intCast(@as(u64, @bitCast(x)) >> 32);
const ix: u32 = hx & 0x7fff_ffff;
// |x| >= 1 or nan
if (ix >= 0x3ff0_0000) {
const lx: u32 = @truncate(@as(u64, @bitCast(x)));
if ((ix - 0x3ff0_0000 | lx) == 0) {
if (hx >> 31 != 0) {
return 2.0 * pio2_hi + 0x1.0p-120;
}
return 0.0;
}
return 0.0 / (x - x);
}
// |x| < 0.5
if (ix < 0x3fe0_0000) {
// |x| < 2^(-57)
if (ix <= 0x3c60_0000) {
return pio2_hi + 0x1.0p-120;
}
return pio2_hi - (x - (pio2_lo - x * rationalApproxBinary64(x * x)));
}
// x < -0.5
if (hx >> 31 != 0) {
const z = (1.0 + x) * 0.5;
const s = @sqrt(z);
const w = rationalApproxBinary64(z) * s - pio2_lo;
return 2 * (pio2_hi - (s + w));
}
// x > 0.5
const z = (1.0 - x) * 0.5;
const s = @sqrt(z);
const df: f64 = @bitCast(@as(u64, @bitCast(s)) & 0xffff_ffff_0000_0000);
const c = (z - df * df) / (s + df);
const w = rationalApproxBinary64(z) * s + c;
return 2.0 * (df + w);
}
fn rationalApproxExtended80(z: f80) f80 {
const pS0: f80 = 1.66666666666666666631e-01;
const pS1: f80 = -4.16313987993683104320e-01;
const pS2: f80 = 3.69068046323246813704e-01;
const pS3: f80 = -1.36213932016738603108e-01;
const pS4: f80 = 1.78324189708471965733e-02;
const pS5: f80 = -2.19216428382605211588e-04;
const pS6: f80 = -7.10526623669075243183e-06;
const qS1: f80 = -2.94788392796209867269e+00;
const qS2: f80 = 3.27309890266528636716e+00;
const qS3: f80 = -1.68285799854822427013e+00;
const qS4: f80 = 3.90699412641738801874e-01;
const qS5: f80 = -3.14365703596053263322e-02;
const p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * (pS5 + z * pS6))))));
const q = 1.0 + z * (qS1 + z * (qS2 + z * (qS3 + z * (qS4 + z * qS5))));
return p / q;
}
fn acosExtended80(x: f80) f80 {
const pio2_hi: f80 = 1.57079632679489661926;
const pio2_lo: f80 = -2.50827880633416601173e-20;
const hx: u80 = @bitCast(x);
const se: u16 = @truncate(hx >> 64);
const e = se & 0x7fff;
// |x| >= 1 or nan
if (e >= 0x3fff) {
if (x == 1.0) {
return 0.0;
}
if (x == -1.0) {
return 2.0 * pio2_hi + 0x1p-120;
}
return 0.0 / (x - x);
}
// |x| < 0.5
if (e < 0x3fff - 1) {
if (e < 0x3fff - math.floatFractionalBits(f80)) {
return pio2_hi + 0x1p-120;
}
return pio2_hi - (rationalApproxExtended80(x * x) * x - pio2_lo + x);
}
// x < -0.5
if (se >> 15 != 0) {
const z = (1 + x) * 0.5;
const s = @sqrt(z);
return 2.0 * (pio2_hi - (rationalApproxExtended80(z) * s - pio2_lo + s));
}
// x > 0.5
const z = (1.0 - x) * 0.5;
const s = @sqrt(z);
const hs: u80 = @bitCast(s);
const f: f80 = @bitCast(hs & 0xffff_ffff_ffff_0000_0000);
const c = (z - f * f) / (s + f);
return 2.0 * (rationalApproxExtended80(z) * s + c + f);
}
fn rationalApproxBinary128(z: f128) f128 {
const pS0: f128 = 1.66666666666666666666666666666700314e-01;
const pS1: f128 = -7.32816946414566252574527475428622708e-01;
const pS2: f128 = 1.34215708714992334609030036562143589e+00;
const pS3: f128 = -1.32483151677116409805070261790752040e+00;
const pS4: f128 = 7.61206183613632558824485341162121989e-01;
const pS5: f128 = -2.56165783329023486777386833928147375e-01;
const pS6: f128 = 4.80718586374448793411019434585413855e-02;
const pS7: f128 = -4.42523267167024279410230886239774718e-03;
const pS8: f128 = 1.44551535183911458253205638280410064e-04;
const pS9: f128 = -2.10558957916600254061591040482706179e-07;
const qS1: f128 = -4.84690167848739751544716485245697428e+00;
const qS2: f128 = 9.96619113536172610135016921140206980e+00;
const qS3: f128 = -1.13177895428973036660836798461641458e+01;
const qS4: f128 = 7.74004374389488266169304117714658761e+00;
const qS5: f128 = -3.25871986053534084709023539900339905e+00;
const qS6: f128 = 8.27830318881232209752469022352928864e-01;
const qS7: f128 = -1.18768052702942805423330715206348004e-01;
const qS8: f128 = 8.32600764660522313269101537926539470e-03;
const qS9: f128 = -1.99407384882605586705979504567947007e-04;
const p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * (pS5 + z * (pS6 + z * (pS7 + z * (pS8 + z * pS9)))))))));
const q = 1.0 + z * (qS1 + z * (qS2 + z * (qS3 + z * (qS4 + z * (qS5 + z * (qS6 + z * (qS7 + z * (qS8 + z * qS9))))))));
return p / q;
}
fn acosBinary128(x: f128) f128 {
const pio2_hi: f128 = 1.57079632679489661923132169163975140;
const pio2_lo: f128 = 4.33590506506189051239852201302167613e-35;
const hx: u128 = @bitCast(x);
const se: u16 = @truncate(hx >> 112);
const e = se & 0x7fff;
// |x| >= 1 or nan
if (e >= 0x3fff) {
if (x == 1.0) {
return 0.0;
}
if (x == -1.0) {
return 2 * pio2_hi + 0x1p-120;
}
return 0.0 / (x - x);
}
// |x| < 0.5
if (e < 0x3fff - 1) {
if (e < 0x3fff - math.floatFractionalBits(f128)) {
return pio2_hi + 0x1p-120;
}
return pio2_hi - (rationalApproxBinary128(x * x) * x - pio2_lo + x);
}
// x < -0.5
if (se >> 15 != 0) {
const z = (1 + x) * 0.5;
const s = @sqrt(z);
return 2 * (pio2_hi - (rationalApproxBinary128(z) * s - pio2_lo + s));
}
// x > 0.5
const z = (1.0 - x) * 0.5;
const s = @sqrt(z);
const hs: u128 = @bitCast(s);
const f: f128 = @bitCast(hs & 0xffff_ffff_ffff_ffff_0000_0000_0000_0000);
const c = (z - f * f) / (s + f);
return 2.0 * (rationalApproxBinary128(z) * s + c + f);
}
test "acosBinary16.special" {
try testing.expectApproxEqAbs(0x1.92p0, acosBinary16(0x0p+0), math.floatEpsAt(f16, 0x1.92p0));
try testing.expectApproxEqAbs(0x1.92p1, acosBinary16(-0x1p+0), math.floatEpsAt(f16, 0x1.92p1));
try testing.expectEqual(0x0p+0, acosBinary16(0x1p+0));
try testing.expect(math.isNan(acosBinary16(0x1.004p0)));
try testing.expect(math.isNan(acosBinary16(-0x1.004p0)));
try testing.expect(math.isNan(acosBinary16(math.inf(f16))));
try testing.expect(math.isNan(acosBinary16(-math.inf(f16))));
try testing.expect(math.isNan(acosBinary16(math.nan(f16))));
}
test "acosBinary16" {
try testing.expectApproxEqAbs(0x1.834p0, acosBinary16(0x1.db4p-5), math.floatEpsAt(f16, 0x1.834p0));
try testing.expectApproxEqAbs(0x1.d48p0, acosBinary16(-0x1.068p-2), math.floatEpsAt(f16, 0x1.d48p0));
try testing.expectApproxEqAbs(0x1.b7cp0, acosBinary16(-0x1.2c4p-3), math.floatEpsAt(f16, 0x1.b7cp0));
try testing.expectApproxEqAbs(0x1.654p0, acosBinary16(0x1.65p-3), math.floatEpsAt(f16, 0x1.654p0));
try testing.expectApproxEqAbs(0x1.6d8p-2, acosBinary16(0x1.dfcp-1), math.floatEpsAt(f16, 0x1.6d8p-2));
try testing.expectApproxEqAbs(0x1.32p1, acosBinary16(-0x1.764p-1), math.floatEpsAt(f16, 0x1.32p1));
try testing.expectApproxEqAbs(0x1.5b8p0, acosBinary16(0x1.b18p-3), math.floatEpsAt(f16, 0x1.5b8p0));
try testing.expectApproxEqAbs(0x1.668p0, acosBinary16(0x1.5acp-3), math.floatEpsAt(f16, 0x1.668p0));
try testing.expectApproxEqAbs(0x1.134p1, acosBinary16(-0x1.18cp-1), math.floatEpsAt(f16, 0x1.134p1));
try testing.expectApproxEqAbs(0x1.0dp1, acosBinary16(-0x1.03p-1), math.floatEpsAt(f16, 0x1.0dp1));
}
test "acosBinary32.special" {
try testing.expectApproxEqAbs(0x1.921fb6p+0, acosBinary32(0x0p+0), math.floatEpsAt(f32, 0x1.921fb6p+0));
try testing.expectApproxEqAbs(0x1.921fb6p+1, acosBinary32(-0x1p+0), math.floatEpsAt(f32, 0x1.921fb6p+1));
try testing.expectEqual(0x0p+0, acosBinary32(0x1p+0));
try testing.expect(math.isNan(acosBinary32(0x1.000002p+0)));
try testing.expect(math.isNan(acosBinary32(-0x1.000002p+0)));
try testing.expect(math.isNan(acosBinary32(math.inf(f32))));
try testing.expect(math.isNan(acosBinary32(-math.inf(f32))));
try testing.expect(math.isNan(acosBinary32(math.nan(f32))));
}
test "acosBinary32" {
try testing.expectApproxEqAbs(0x1.d7c4e6p+0, acosBinary32(-0x1.13284cp-2), math.floatEpsAt(f32, 0x1.d7c4e6p+0));
try testing.expectApproxEqAbs(0x1.8e6756p-1, acosBinary32(0x1.6ca8ep-1), math.floatEpsAt(f32, 0x1.8e6756p-1));
try testing.expectApproxEqAbs(0x1.f9d74cp-2, acosBinary32(0x1.c2ca6p-1), math.floatEpsAt(f32, 0x1.f9d74cp-2));
try testing.expectApproxEqAbs(0x1.26abdcp+1, acosBinary32(-0x1.55f12p-1), math.floatEpsAt(f32, 0x1.26abdcp+1));
try testing.expectApproxEqAbs(0x1.d85a44p+0, acosBinary32(-0x1.15679ep-2), math.floatEpsAt(f32, 0x1.d85a44p+0));
try testing.expectApproxEqAbs(0x1.9c2f68p+0, acosBinary32(-0x1.41e132p-5), math.floatEpsAt(f32, 0x1.9c2f68p+0));
try testing.expectApproxEqAbs(0x1.e881bp-1, acosBinary32(0x1.281b0ep-1), math.floatEpsAt(f32, 0x1.e881bp-1));
try testing.expectApproxEqAbs(0x1.1713f6p-1, acosBinary32(0x1.b5ce34p-1), math.floatEpsAt(f32, 0x1.1713f6p-1));
try testing.expectApproxEqAbs(0x1.bd5accp+0, acosBinary32(-0x1.583482p-3), math.floatEpsAt(f32, 0x1.bd5accp+0));
try testing.expectApproxEqAbs(0x1.6ce7d8p+1, acosBinary32(-0x1.ea8224p-1), math.floatEpsAt(f32, 0x1.6ce7d8p+1));
}
test "acosBinary64.special" {
try testing.expectApproxEqAbs(0x1.921fb54442d18p+0, acosBinary64(0x0p+0), math.floatEpsAt(f64, 0x1.921fb54442d18p+0));
try testing.expectApproxEqAbs(0x1.921fb54442d18p+1, acosBinary64(-0x1p+0), math.floatEpsAt(f64, 0x1.921fb54442d18p+1));
try testing.expectEqual(0x0p+0, acosBinary64(0x1p+0));
try testing.expect(math.isNan(acosBinary64(0x1.0000000000001p+0)));
try testing.expect(math.isNan(acosBinary64(-0x1.0000000000001p+0)));
try testing.expect(math.isNan(acosBinary64(math.inf(f64))));
try testing.expect(math.isNan(acosBinary64(-math.inf(f64))));
try testing.expect(math.isNan(acosBinary64(math.nan(f64))));
}
test "acosBinary64" {
try testing.expectApproxEqAbs(0x1.d7c4e61020905p+0, acosBinary64(-0x1.13284b2b5006dp-2), math.floatEpsAt(f64, 0x1.d7c4e61020905p+0));
try testing.expectApproxEqAbs(0x1.8e6756e27c366p-1, acosBinary64(0x1.6ca8dfb825911p-1), math.floatEpsAt(f64, 0x1.8e6756e27c366p-1));
try testing.expectApproxEqAbs(0x1.f9d748eaf956p-2, acosBinary64(0x1.c2ca609de7505p-1), math.floatEpsAt(f64, 0x1.f9d748eaf956p-2));
try testing.expectApproxEqAbs(0x1.26abdc68d07aap+1, acosBinary64(-0x1.55f11fba96889p-1), math.floatEpsAt(f64, 0x1.26abdc68d07aap+1));
try testing.expectApproxEqAbs(0x1.d85a44ea44fe4p+0, acosBinary64(-0x1.15679e27084ddp-2), math.floatEpsAt(f64, 0x1.d85a44ea44fe4p+0));
try testing.expectApproxEqAbs(0x1.9c2f688eee8abp+0, acosBinary64(-0x1.41e131b093c41p-5), math.floatEpsAt(f64, 0x1.9c2f688eee8abp+0));
try testing.expectApproxEqAbs(0x1.e881b1d4eb2a1p-1, acosBinary64(0x1.281b0d18455f5p-1), math.floatEpsAt(f64, 0x1.e881b1d4eb2a1p-1));
try testing.expectApproxEqAbs(0x1.1713f567a87efp-1, acosBinary64(0x1.b5ce34a51b239p-1), math.floatEpsAt(f64, 0x1.1713f567a87efp-1));
try testing.expectApproxEqAbs(0x1.bd5acbe8fcc59p+0, acosBinary64(-0x1.583481079de4dp-3), math.floatEpsAt(f64, 0x1.bd5acbe8fcc59p+0));
try testing.expectApproxEqAbs(0x1.6ce7d66f628e5p+1, acosBinary64(-0x1.ea8223103b871p-1), math.floatEpsAt(f64, 0x1.6ce7d66f628e5p+1));
}
test "acosExtended80.special" {
try testing.expectApproxEqAbs(0x1.921fb54442d1846ap+0, acosExtended80(0x0p+0), math.floatEpsAt(f80, 0x1.921fb54442d1846ap+0));
try testing.expectApproxEqAbs(0x1.921fb54442d1846ap+1, acosExtended80(-0x1p+0), math.floatEpsAt(f80, 0x1.921fb54442d1846ap+1));
try testing.expectEqual(0x0p+0, acosExtended80(0x1p+0));
try testing.expect(math.isNan(acosExtended80(0x1.0000000000000002p+0)));
try testing.expect(math.isNan(acosExtended80(-0x1.0000000000000002p+0)));
try testing.expect(math.isNan(acosExtended80(math.inf(f80))));
try testing.expect(math.isNan(acosExtended80(-math.inf(f80))));
try testing.expect(math.isNan(acosExtended80(math.nan(f80))));
}
test "acosExtended80" {
try testing.expectApproxEqAbs(0x1.86b349040d28f794p-1, acosExtended80(0x1.72068a321edc8804p-1), math.floatEpsAt(f80, 0x1.86b349040d28f794p-1));
try testing.expectApproxEqAbs(0x1.d4923ade73ec379cp0, acosExtended80(-0x1.06d0a467d22977ecp-2), math.floatEpsAt(f80, 0x1.d4923ade73ec379cp0));
try testing.expectApproxEqAbs(0x1.62e0e8898c6d04f2p0, acosExtended80(0x1.77d21385faa9798ap-3), math.floatEpsAt(f80, 0x1.62e0e8898c6d04f2p0));
try testing.expectApproxEqAbs(0x1.3123cbcd5dc4bd58p1, acosExtended80(-0x1.73ee3e8bc2a44dbep-1), math.floatEpsAt(f80, 0x1.3123cbcd5dc4bd58p1));
try testing.expectApproxEqAbs(0x1.062a6d562df2d316p0, acosExtended80(0x1.0a2dd1f6ffcf668ap-1), math.floatEpsAt(f80, 0x1.062a6d562df2d316p0));
try testing.expectApproxEqAbs(0x1.5ffd68b520aa55fap0, acosExtended80(0x1.8e835c490a3aff9ep-3), math.floatEpsAt(f80, 0x1.5ffd68b520aa55fap0));
try testing.expectApproxEqAbs(0x1.5bfe6cabda700684p0, acosExtended80(0x1.add20cdc1565064cp-3), math.floatEpsAt(f80, 0x1.5bfe6cabda700684p0));
try testing.expectApproxEqAbs(0x1.90fe1c993b571924p0, acosExtended80(0x1.21986d43727fca72p-8), math.floatEpsAt(f80, 0x1.90fe1c993b571924p0));
try testing.expectApproxEqAbs(0x1.18044ccc626e7f9ep0, acosExtended80(0x1.d61e0b3fae6a0564p-2), math.floatEpsAt(f80, 0x1.18044ccc626e7f9ep0));
try testing.expectApproxEqAbs(0x1.a39513b6c16532b4p0, acosExtended80(-0x1.171e7c4a41883ccap-4), math.floatEpsAt(f80, 0x1.a39513b6c16532b4p0));
}
test "acosBinary128.special" {
try testing.expectApproxEqAbs(0x1.921fb54442d18469898cc51701b8p0, acosBinary128(0x0p+0), math.floatEpsAt(f128, 0x1.921fb54442d18469898cc51701b8p0));
try testing.expectApproxEqAbs(0x1.921fb54442d18469898cc51701b8p1, acosBinary128(-0x1p+0), math.floatEpsAt(f128, 0x1.921fb54442d18469898cc51701b8p1));
try testing.expectEqual(0x0p+0, acosBinary128(0x1p+0));
try testing.expect(math.isNan(acosBinary128(0x1.0000000000000000000000000001p0)));
try testing.expect(math.isNan(acosBinary128(-0x1.0000000000000000000000000001p0)));
try testing.expect(math.isNan(acosBinary128(math.inf(f128))));
try testing.expect(math.isNan(acosBinary128(-math.inf(f128))));
try testing.expect(math.isNan(acosBinary128(math.nan(f128))));
}
test "acosBinary128" {
try testing.expectApproxEqAbs(0x1.250e9a58f049eeafa99db4360c88p1, acosBinary128(-0x1.511bdb99a3c4373bedf834ef4f68p-1), math.floatEpsAt(f128, 0x1.250e9a58f049eeafa99db4360c88p1));
try testing.expectApproxEqAbs(0x1.2786664b1c676c99437b68590004p1, acosBinary128(-0x1.5879cc3ad6dfd2a52e9891c69808p-1), math.floatEpsAt(f128, 0x1.2786664b1c676c99437b68590004p1));
try testing.expectApproxEqAbs(0x1.cb190cd361c7c03a09c470b4caebp-1, acosBinary128(0x1.3f988ba64a7eb97a751c5f0b3077p-1), math.floatEpsAt(f128, 0x1.cb190cd361c7c03a09c470b4caebp-1));
try testing.expectApproxEqAbs(0x1.1f373be697880111758f582b1a96p1, acosBinary128(-0x1.3f2d96c7768e4c4fa02315727959p-1), math.floatEpsAt(f128, 0x1.1f373be697880111758f582b1a96p1));
try testing.expectApproxEqAbs(0x1.0d92fd2a0a6ca3e4853c1de9ea6ap0, acosBinary128(0x1.fad303c2e28c1f4d8f9fd0e5686fp-2), math.floatEpsAt(f128, 0x1.0d92fd2a0a6ca3e4853c1de9ea6ap0));
try testing.expectApproxEqAbs(0x1.15d4b306e16fbf9ea4f29e82b154p0, acosBinary128(0x1.ddde322bd1a2ee50c5ba30c9c617p-2), math.floatEpsAt(f128, 0x1.15d4b306e16fbf9ea4f29e82b154p0));
try testing.expectApproxEqAbs(0x1.49b0a0355a5539052388e8a6dc11p1, acosBinary128(-0x1.b02f6adefcbeb1d48666b827ff17p-1), math.floatEpsAt(f128, 0x1.49b0a0355a5539052388e8a6dc11p1));
try testing.expectApproxEqAbs(0x1.1be0b757f4cef022f5d2422b9c78p0, acosBinary128(0x1.c8581cce7cd3f6efab0fc60d9b7dp-2), math.floatEpsAt(f128, 0x1.1be0b757f4cef022f5d2422b9c78p0));
try testing.expectApproxEqAbs(0x1.513270e671db2d840f20b0186c2cp1, acosBinary128(-0x1.bf887b8c4e33cbef59993056f3dep-1), math.floatEpsAt(f128, 0x1.513270e671db2d840f20b0186c2cp1));
try testing.expectApproxEqAbs(0x1.70851a509f0e8bfbe780aa8f29f9p0, acosBinary128(0x1.0c0f600ab6f9c84c6102942044cep-3), math.floatEpsAt(f128, 0x1.70851a509f0e8bfbe780aa8f29f9p0));
}
fn acosBinary32Vec(comptime vec_len: comptime_int, x: @Vector(vec_len, f32)) @TypeOf(x) {
const pi: @Vector(vec_len, f32) = @splat(math.pi);
const pi_over_2: @Vector(vec_len, f32) = @splat(math.pi / 2.0);
const zero: @Vector(vec_len, f32) = @splat(0.0);
const half: @Vector(vec_len, f32) = @splat(0.5);
const neg_one: @Vector(vec_len, f32) = @splat(-1.0);
const two: @Vector(vec_len, f32) = @splat(2.0);
const c0: @Vector(vec_len, f32) = @splat(0x1.55555ep-3);
const c1: @Vector(vec_len, f32) = @splat(0x1.33261ap-4);
const c2: @Vector(vec_len, f32) = @splat(0x1.70d7dcp-5);
const c3: @Vector(vec_len, f32) = @splat(0x1.b059dp-6);
const c4: @Vector(vec_len, f32) = @splat(0x1.3af7d8p-5);
const ax = @abs(x);
const ax_lt_half = ax < half;
const is_neg = x < zero;
const z2 = @select(f32, ax_lt_half, x * x, @mulAdd(@Vector(vec_len, f32), -half, ax, half));
const z = @select(f32, ax_lt_half, ax, @sqrt(z2));
const z3 = z2 * z;
const p3_4 = @mulAdd(@Vector(vec_len, f32), z2, c4, c3);
const p2_4 = @mulAdd(@Vector(vec_len, f32), z2, p3_4, c2);
const p1_4 = @mulAdd(@Vector(vec_len, f32), z2, p2_4, c1);
const p0_4 = @mulAdd(@Vector(vec_len, f32), z2, p1_4, c0);
const p = @mulAdd(@Vector(vec_len, f32), z3, p0_4, z);
const mul = @select(f32, ax_lt_half, neg_one, two);
const add = @select(f32, ax_lt_half, pi_over_2, @select(f32, is_neg, pi, zero));
return @mulAdd(@Vector(vec_len, f32), mul, @select(f32, is_neg, -p, p), add);
}
fn acosBinary64Vec(comptime vec_len: comptime_int, x: @Vector(vec_len, f64)) @TypeOf(x) {
const pi: @Vector(vec_len, f64) = @splat(math.pi);
const pi_over_2: @Vector(vec_len, f64) = @splat(math.pi / 2.0);
const zero: @Vector(vec_len, f64) = @splat(0.0);
const half: @Vector(vec_len, f64) = @splat(0.5);
const neg_one: @Vector(vec_len, f64) = @splat(-1.0);
const two: @Vector(vec_len, f64) = @splat(2.0);
const c0: @Vector(vec_len, f64) = @splat(0x1.555555555554ep-3);
const c1: @Vector(vec_len, f64) = @splat(0x1.3333333337233p-4);
const c2: @Vector(vec_len, f64) = @splat(0x1.6db6db67f6d9fp-5);
const c3: @Vector(vec_len, f64) = @splat(0x1.f1c71fbd29fbbp-6);
const c4: @Vector(vec_len, f64) = @splat(0x1.6e8b264d467d6p-6);
const c5: @Vector(vec_len, f64) = @splat(0x1.1c5997c357e9dp-6);
const c6: @Vector(vec_len, f64) = @splat(0x1.c86a22cd9389dp-7);
const c7: @Vector(vec_len, f64) = @splat(0x1.856073c22ebbep-7);
const c8: @Vector(vec_len, f64) = @splat(0x1.fd1151acb6bedp-8);
const c9: @Vector(vec_len, f64) = @splat(0x1.087182f799c1dp-6);
const c10: @Vector(vec_len, f64) = @splat(-0x1.6602748120927p-7);
const c11: @Vector(vec_len, f64) = @splat(0x1.cfa0dd1f9478p-6);
const ax = @abs(x);
const ax_lt_half = ax < half;
const is_neg = x < zero;
const z2 = @select(f64, ax_lt_half, x * x, @mulAdd(@Vector(vec_len, f64), -half, ax, half));
const z = @select(f64, ax_lt_half, ax, @sqrt(z2));
const z3 = z2 * z;
const z4 = z2 * z2;
const z8 = z4 * z4;
const p0_1 = @mulAdd(@Vector(vec_len, f64), z2, c1, c0);
const p2_3 = @mulAdd(@Vector(vec_len, f64), z2, c3, c2);
const p0_3 = @mulAdd(@Vector(vec_len, f64), z4, p2_3, p0_1);
const p4_5 = @mulAdd(@Vector(vec_len, f64), z2, c5, c4);
const p6_7 = @mulAdd(@Vector(vec_len, f64), z2, c7, c6);
const p4_7 = @mulAdd(@Vector(vec_len, f64), z4, p6_7, p4_5);
const p8_9 = @mulAdd(@Vector(vec_len, f64), z2, c9, c8);
const p10_11 = @mulAdd(@Vector(vec_len, f64), z2, c11, c10);
const p8_11 = @mulAdd(@Vector(vec_len, f64), z4, p10_11, p8_9);
const p4_11 = @mulAdd(@Vector(vec_len, f64), z8, p8_11, p4_7);
const p0_11 = @mulAdd(@Vector(vec_len, f64), z8, p4_11, p0_3);
const p = @mulAdd(@Vector(vec_len, f64), z3, p0_11, z);
const mul = @select(f64, ax_lt_half, neg_one, two);
const add = @select(f64, ax_lt_half, pi_over_2, @select(f64, is_neg, pi, zero));
return @mulAdd(@Vector(vec_len, f64), mul, @select(f64, is_neg, -p, p), add);
}
test "acosBinary32Vec.special" {
const input: @Vector(8, f32) = .{
0x0p+0,
-0x1p+0,
0x1p+0,
0x1.000002p+0,
-0x1.000002p+0,
math.inf(f32),
-math.inf(f32),
math.nan(f32),
};
const output = acosBinary32Vec(8, input);
try testing.expectApproxEqAbs(0x1.921fb6p+0, output[0], math.floatEpsAt(f32, 0x1.921fb6p+0));
try testing.expectApproxEqAbs(0x1.921fb6p+1, output[1], math.floatEpsAt(f32, 0x1.921fb6p+1));
try testing.expectEqual(0x0p+0, output[2]);
try testing.expect(math.isNan(output[3]));
try testing.expect(math.isNan(output[4]));
try testing.expect(math.isNan(output[5]));
try testing.expect(math.isNan(output[6]));
try testing.expect(math.isNan(output[7]));
}
test "acosBinary32Vec" {
const input: @Vector(10, f32) = .{
-0x1.13284cp-2,
0x1.6ca8ep-1,
0x1.c2ca6p-1,
-0x1.55f12p-1,
-0x1.15679ep-2,
-0x1.41e132p-5,
0x1.281b0ep-1,
0x1.b5ce34p-1,
-0x1.583482p-3,
-0x1.ea8224p-1,
};
const output = acosBinary32Vec(10, input);
try testing.expectApproxEqAbs(0x1.d7c4e6p+0, output[0], math.floatEpsAt(f32, 0x1.d7c4e6p+0));
try testing.expectApproxEqAbs(0x1.8e6756p-1, output[1], math.floatEpsAt(f32, 0x1.8e6756p-1));
try testing.expectApproxEqAbs(0x1.f9d74cp-2, output[2], math.floatEpsAt(f32, 0x1.f9d74cp-2));
try testing.expectApproxEqAbs(0x1.26abdcp+1, output[3], math.floatEpsAt(f32, 0x1.26abdcp+1));
try testing.expectApproxEqAbs(0x1.d85a44p+0, output[4], math.floatEpsAt(f32, 0x1.d85a44p+0));
try testing.expectApproxEqAbs(0x1.9c2f68p+0, output[5], math.floatEpsAt(f32, 0x1.9c2f68p+0));
try testing.expectApproxEqAbs(0x1.e881bp-1, output[6], math.floatEpsAt(f32, 0x1.e881bp-1));
try testing.expectApproxEqAbs(0x1.1713f6p-1, output[7], math.floatEpsAt(f32, 0x1.1713f6p-1));
try testing.expectApproxEqAbs(0x1.bd5accp+0, output[8], math.floatEpsAt(f32, 0x1.bd5accp+0));
try testing.expectApproxEqAbs(0x1.6ce7d8p+1, output[9], math.floatEpsAt(f32, 0x1.6ce7d8p+1));
}
test "acosBinary64Vec.special" {
const input: @Vector(8, f64) = .{
0x0p+0,
-0x1p+0,
0x1p+0,
0x1.0000000000001p+0,
-0x1.0000000000001p+0,
math.inf(f64),
-math.inf(f64),
math.nan(f64),
};
const output = acosBinary64Vec(8, input);
try testing.expectApproxEqAbs(0x1.921fb54442d18p+0, output[0], math.floatEpsAt(f64, 0x1.921fb54442d18p+0));
try testing.expectApproxEqAbs(0x1.921fb54442d18p+1, output[1], math.floatEpsAt(f64, 0x1.921fb54442d18p+1));
try testing.expectEqual(0x0p+0, output[2]);
try testing.expect(math.isNan(output[3]));
try testing.expect(math.isNan(output[4]));
try testing.expect(math.isNan(output[5]));
try testing.expect(math.isNan(output[6]));
try testing.expect(math.isNan(output[7]));
}
test "acosBinary64Vec" {
const input: @Vector(10, f64) = .{
-0x1.13284b2b5006dp-2,
0x1.6ca8dfb825911p-1,
0x1.c2ca609de7505p-1,
-0x1.55f11fba96889p-1,
-0x1.15679e27084ddp-2,
-0x1.41e131b093c41p-5,
0x1.281b0d18455f5p-1,
0x1.b5ce34a51b239p-1,
-0x1.583481079de4dp-3,
-0x1.ea8223103b871p-1,
};
const output = acosBinary64Vec(10, input);
try testing.expectApproxEqAbs(0x1.d7c4e61020905p+0, output[0], math.floatEpsAt(f64, 0x1.d7c4e61020905p+0));
try testing.expectApproxEqAbs(0x1.8e6756e27c366p-1, output[1], math.floatEpsAt(f64, 0x1.8e6756e27c366p-1));
try testing.expectApproxEqAbs(0x1.f9d748eaf956p-2, output[2], math.floatEpsAt(f64, 0x1.f9d748eaf956p-2));
try testing.expectApproxEqAbs(0x1.26abdc68d07aap+1, output[3], math.floatEpsAt(f64, 0x1.26abdc68d07aap+1));
try testing.expectApproxEqAbs(0x1.d85a44ea44fe4p+0, output[4], math.floatEpsAt(f64, 0x1.d85a44ea44fe4p+0));
try testing.expectApproxEqAbs(0x1.9c2f688eee8abp+0, output[5], math.floatEpsAt(f64, 0x1.9c2f688eee8abp+0));
try testing.expectApproxEqAbs(0x1.e881b1d4eb2a1p-1, output[6], math.floatEpsAt(f64, 0x1.e881b1d4eb2a1p-1));
try testing.expectApproxEqAbs(0x1.1713f567a87efp-1, output[7], math.floatEpsAt(f64, 0x1.1713f567a87efp-1));
try testing.expectApproxEqAbs(0x1.bd5acbe8fcc59p+0, output[8], math.floatEpsAt(f64, 0x1.bd5acbe8fcc59p+0));
try testing.expectApproxEqAbs(0x1.6ce7d66f628e5p+1, output[9], math.floatEpsAt(f64, 0x1.6ce7d66f628e5p+1));
}