22 lines
577 B
Zig
22 lines
577 B
Zig
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, z.im)) {
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const T = @TypeOf(z.re, z.im);
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const p = Complex(T).init(-z.im, z.re);
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return cmath.cosh(p);
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}
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test cos {
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const epsilon = math.floatEps(f32);
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const a = Complex(f32).init(5, 3);
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const c = cos(a);
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try testing.expectApproxEqAbs(2.8558152, c.re, epsilon);
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try testing.expectApproxEqAbs(9.606383, c.im, epsilon);
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}
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