/usr/share/go-1.6/src/runtime/complex.go is in golang-1.6-src 1.6.1-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 | // Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
func isposinf(f float64) bool { return f > maxFloat64 }
func isneginf(f float64) bool { return f < -maxFloat64 }
func isnan(f float64) bool { return f != f }
func nan() float64 {
var f float64 = 0
return f / f
}
func posinf() float64 {
var f float64 = maxFloat64
return f * f
}
func neginf() float64 {
var f float64 = maxFloat64
return -f * f
}
func complex128div(n complex128, d complex128) complex128 {
// Special cases as in C99.
ninf := isposinf(real(n)) || isneginf(real(n)) ||
isposinf(imag(n)) || isneginf(imag(n))
dinf := isposinf(real(d)) || isneginf(real(d)) ||
isposinf(imag(d)) || isneginf(imag(d))
nnan := !ninf && (isnan(real(n)) || isnan(imag(n)))
dnan := !dinf && (isnan(real(d)) || isnan(imag(d)))
switch {
case nnan || dnan:
return complex(nan(), nan())
case ninf && !dinf:
return complex(posinf(), posinf())
case !ninf && dinf:
return complex(0, 0)
case real(d) == 0 && imag(d) == 0:
if real(n) == 0 && imag(n) == 0 {
return complex(nan(), nan())
} else {
return complex(posinf(), posinf())
}
default:
// Standard complex arithmetic, factored to avoid unnecessary overflow.
a := real(d)
if a < 0 {
a = -a
}
b := imag(d)
if b < 0 {
b = -b
}
if a <= b {
ratio := real(d) / imag(d)
denom := real(d)*ratio + imag(d)
return complex((real(n)*ratio+imag(n))/denom,
(imag(n)*ratio-real(n))/denom)
} else {
ratio := imag(d) / real(d)
denom := imag(d)*ratio + real(d)
return complex((imag(n)*ratio+real(n))/denom,
(imag(n)-real(n)*ratio)/denom)
}
}
}
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