28 lines
874 B
Zig
28 lines
874 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 arc-cosine of z.
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pub fn acos(z: anytype) Complex(@TypeOf(z.re)) {
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const T = @TypeOf(z.re);
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const q = cmath.asin(z);
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return Complex(T).new(@as(T, math.pi) / 2 - q.re, -q.im);
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}
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const epsilon = 0.0001;
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test "complex.cacos" {
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const a = Complex(f32).new(5, 3);
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const c = acos(a);
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testing.expect(math.approxEq(f32, c.re, 0.546975, epsilon));
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testing.expect(math.approxEq(f32, c.im, -2.452914, epsilon));
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}
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