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30 lines
905 B
Zig
30 lines
905 B
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2021 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 natural logarithm of z.
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pub fn log(z: anytype) Complex(@TypeOf(z.re)) {
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const T = @TypeOf(z.re);
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const r = cmath.abs(z);
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const phi = cmath.arg(z);
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return Complex(T).init(math.ln(r), phi);
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}
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const epsilon = 0.0001;
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test "complex.clog" {
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const a = Complex(f32).init(5, 3);
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const c = log(a);
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try testing.expect(math.approxEqAbs(f32, c.re, 1.763180, epsilon));
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try testing.expect(math.approxEqAbs(f32, c.im, 0.540419, epsilon));
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}
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