22 lines
608 B
Zig
22 lines
608 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 arc-cosine of z.
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pub fn acos(z: anytype) Complex(@TypeOf(z.re, z.im)) {
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const T = @TypeOf(z.re, z.im);
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const q = cmath.asin(z);
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return Complex(T).init(@as(T, math.pi) / 2 - q.re, -q.im);
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}
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test acos {
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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 = acos(a);
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try testing.expectApproxEqAbs(0.5469737, c.re, epsilon);
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try testing.expectApproxEqAbs(-2.4529128, c.im, epsilon);
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}
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