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