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std: Fix complex ldexp implementation

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Two bugs in the implementation ported from musl made all the complex
functions relying on ldexp return incorrect results in some cases.

Spotted in #9047
This commit is contained in:
LemonBoy
2021-06-12 15:35:52 +02:00
committed by Veikka Tuominen
parent 0d022eb1d6
commit 44cdafd9d4
2 changed files with 40 additions and 14 deletions
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42
lib/std/math/complex/exp.zig
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@@ -124,20 +124,42 @@ fn exp64(z: Complex(f64)) Complex(f64) {
}
}
const epsilon = 0.0001;
test "complex.cexp32" {
const a = Complex(f32).init(5, 3);
const c = exp(a);
const tolerance_f32 = math.sqrt(math.epsilon(f32));
try testing.expect(math.approxEqAbs(f32, c.re, -146.927917, epsilon));
try testing.expect(math.approxEqAbs(f32, c.im, 20.944065, epsilon));
{
const a = Complex(f32).init(5, 3);
const c = exp(a);
try testing.expectApproxEqRel(@as(f32, -1.46927917e+02), c.re, tolerance_f32);
try testing.expectApproxEqRel(@as(f32, 2.0944065e+01), c.im, tolerance_f32);
}
{
const a = Complex(f32).init(88.8, 0x1p-149);
const c = exp(a);
try testing.expectApproxEqAbs(math.inf(f32), c.re, tolerance_f32);
try testing.expectApproxEqAbs(@as(f32, 5.15088629e-07), c.im, tolerance_f32);
}
}
test "complex.cexp64" {
const a = Complex(f64).init(5, 3);
const c = exp(a);
const tolerance_f64 = math.sqrt(math.epsilon(f64));
try testing.expect(math.approxEqAbs(f64, c.re, -146.927917, epsilon));
try testing.expect(math.approxEqAbs(f64, c.im, 20.944065, epsilon));
{
const a = Complex(f64).init(5, 3);
const c = exp(a);
try testing.expectApproxEqRel(@as(f64, -1.469279139083189e+02), c.re, tolerance_f64);
try testing.expectApproxEqRel(@as(f64, 2.094406620874596e+01), c.im, tolerance_f64);
}
{
const a = Complex(f64).init(709.8, 0x1p-1074);
const c = exp(a);
try testing.expectApproxEqAbs(math.inf(f64), c.re, tolerance_f64);
try testing.expectApproxEqAbs(@as(f64, 9.036659362159884e-16), c.im, tolerance_f64);
}
}