28 lines
750 B
Zig
28 lines
750 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-sine of z.
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pub fn asin(z: anytype) Complex(@TypeOf(z.re, z.im)) {
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const T = @TypeOf(z.re, z.im);
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const x = z.re;
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const y = z.im;
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const p = Complex(T).init(1.0 - (x - y) * (x + y), -2.0 * x * y);
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const q = Complex(T).init(-y, x);
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const r = cmath.log(q.add(cmath.sqrt(p)));
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return Complex(T).init(r.im, -r.re);
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}
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test asin {
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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 = asin(a);
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try testing.expectApproxEqAbs(1.0238227, c.re, epsilon);
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try testing.expectApproxEqAbs(2.4529128, c.im, epsilon);
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}
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