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| // Copyright 2009-2010 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 math
|
| /*
| Floating-point mod function.
| */
|
| // Mod returns the floating-point remainder of x/y.
| // The magnitude of the result is less than y and its
| // sign agrees with that of x.
| //
| // Special cases are:
| // Mod(±Inf, y) = NaN
| // Mod(NaN, y) = NaN
| // Mod(x, 0) = NaN
| // Mod(x, ±Inf) = x
| // Mod(x, NaN) = NaN
| func Mod(x, y float64) float64
|
| func mod(x, y float64) float64 {
| if y == 0 || IsInf(x, 0) || IsNaN(x) || IsNaN(y) {
| return NaN()
| }
| y = Abs(y)
|
| yfr, yexp := Frexp(y)
| r := x
| if x < 0 {
| r = -x
| }
|
| for r >= y {
| rfr, rexp := Frexp(r)
| if rfr < yfr {
| rexp = rexp - 1
| }
| r = r - Ldexp(y, rexp-yexp)
| }
| if x < 0 {
| r = -r
| }
| return r
| }
|
|
