ff14451b4a
Comparisons with absolute epsilons are usually useful when comparing numbers to zero, for non-zero numbers it's advised to switch to relative epsilons instead to obtain meaningful results (check [1] for more details). The new API introduces approxEqAbs and approxEqRel, where the former aliases and deprecated the old `approxEq`, allowing the user to pick the right tool for the job. The documentation is meant to guide the user in the choice of the correct alternative. [1] https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
28 lines
850 B
Zig
28 lines
850 B
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const std = @import("../../std.zig");
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const testing = std.testing;
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const math = std.math;
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const cmath = math.complex;
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const Complex = cmath.Complex;
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/// Returns the cosine of z.
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pub fn cos(z: anytype) Complex(@TypeOf(z.re)) {
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const T = @TypeOf(z.re);
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const p = Complex(T).new(-z.im, z.re);
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return cmath.cosh(p);
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}
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const epsilon = 0.0001;
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test "complex.ccos" {
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const a = Complex(f32).new(5, 3);
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const c = cos(a);
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testing.expect(math.approxEqAbs(f32, c.re, 2.855815, epsilon));
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testing.expect(math.approxEqAbs(f32, c.im, 9.606383, epsilon));
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}
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