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Update atan2.zig (#17840)

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Co-authored-by: castholm <carl@astholm.se>
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expikr 2024-01-15 10:04:30 +08:00 committed by GitHub
parent 1a7a711964
commit f9d8176e94
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3 changed files with 32 additions and 26 deletions
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49
lib/std/math/atan2.zig
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@ -10,25 +10,28 @@ const expect = std.testing.expect;
/// Returns the arc-tangent of y/x.
///
/// Special Cases:
/// - atan2(y, nan) = nan
/// - atan2(nan, x) = nan
/// - atan2(+0, x>=0) = +0
/// - atan2(-0, x>=0) = -0
/// - atan2(+0, x<=-0) = +pi
/// - atan2(-0, x<=-0) = -pi
/// - atan2(y>0, 0) = +pi/2
/// - atan2(y<0, 0) = -pi/2
/// - atan2(+inf, +inf) = +pi/4
/// - atan2(-inf, +inf) = -pi/4
/// - atan2(+inf, -inf) = 3pi/4
/// - atan2(-inf, -inf) = -3pi/4
/// - atan2(y, +inf) = 0
/// - atan2(y>0, -inf) = +pi
/// - atan2(y<0, -inf) = -pi
/// - atan2(+inf, x) = +pi/2
/// - atan2(-inf, x) = -pi/2
pub fn atan2(comptime T: type, y: T, x: T) T {
/// Special Cases:
/// | y | x | radians |
/// |-------|-------|---------|
/// | fin | nan | nan |
/// | nan | fin | nan |
/// | +0 | >=+0 | +0 |
/// | -0 | >=+0 | -0 |
/// | +0 | <=-0 | pi |
/// | -0 | <=-0 | -pi |
/// | pos | 0 | +pi/2 |
/// | neg | 0 | -pi/2 |
/// | +inf | +inf | +pi/4 |
/// | -inf | +inf | -pi/4 |
/// | +inf | -inf | 3pi/4 |
/// | -inf | -inf | -3pi/4 |
/// | fin | +inf | 0 |
/// | pos | -inf | +pi |
/// | neg | -inf | -pi |
/// | +inf | fin | +pi/2 |
/// | -inf | fin | -pi/2 |
pub fn atan2(y: anytype, x: anytype) @TypeOf(x, y) {
const T = @TypeOf(x, y);
return switch (T) {
f32 => atan2_32(y, x),
f64 => atan2_64(y, x),
@ -212,8 +215,12 @@ fn atan2_64(y: f64, x: f64) f64 {
}
test "math.atan2" {
try expect(atan2(f32, 0.2, 0.21) == atan2_32(0.2, 0.21));
try expect(atan2(f64, 0.2, 0.21) == atan2_64(0.2, 0.21));
const y32: f32 = 0.2;
const x32: f32 = 0.21;
const y64: f64 = 0.2;
const x64: f64 = 0.21;
try expect(atan2(y32, x32) == atan2_32(0.2, 0.21));
try expect(atan2(y64, x64) == atan2_64(0.2, 0.21));
}
test "math.atan2_32" {

5
lib/std/math/complex/arg.zig
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@ -5,9 +5,8 @@ const cmath = math.complex;
const Complex = cmath.Complex;
/// Returns the angular component (in radians) of z.
pub fn arg(z: anytype) @TypeOf(z.re) {
const T = @TypeOf(z.re);
return math.atan2(T, z.im, z.re);
pub fn arg(z: anytype) @TypeOf(z.re, z.im) {
return math.atan2(z.im, z.re);
}
const epsilon = 0.0001;

4
lib/std/math/complex/atan.zig
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@ -54,7 +54,7 @@ fn atan32(z: Complex(f32)) Complex(f32) {
return Complex(f32).init(maxnum, maxnum);
}
var t = 0.5 * math.atan2(f32, 2.0 * x, a);
var t = 0.5 * math.atan2(2.0 * x, a);
const w = redupif32(t);
t = y - 1.0;
@ -103,7 +103,7 @@ fn atan64(z: Complex(f64)) Complex(f64) {
return Complex(f64).init(maxnum, maxnum);
}
var t = 0.5 * math.atan2(f64, 2.0 * x, a);
var t = 0.5 * math.atan2(2.0 * x, a);
const w = redupif64(t);
t = y - 1.0;