38 lines
762 B
V
38 lines
762 B
V
module math
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// special cases are:
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// sqrt(+inf) = +inf
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// sqrt(±0) = ±0
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// sqrt(x < 0) = nan
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// sqrt(nan) = nan
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[inline]
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pub fn sqrt(a f64) f64 {
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mut x := a
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if x == 0.0 || is_nan(x) || is_inf(x, 1) {
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return x
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}
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if x < 0.0 {
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return nan()
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}
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z, ex := frexp(x)
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w := x
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// approximate square root of number between 0.5 and 1
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// relative error of approximation = 7.47e-3
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x = 4.173075996388649989089e-1 + 5.9016206709064458299663e-1 * z // adjust for odd powers of 2
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if (ex & 1) != 0 {
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x *= sqrt2
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}
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x = ldexp(x, ex >> 1)
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// newton iterations
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x = 0.5 * (x + w / x)
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x = 0.5 * (x + w / x)
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x = 0.5 * (x + w / x)
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return x
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}
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// sqrtf calculates square-root of the provided value. (float32)
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[inline]
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pub fn sqrtf(a f32) f32 {
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return f32(sqrt(a))
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}
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