summaryrefslogtreecommitdiff
path: root/src/pkg/math/hypot_port.go
diff options
context:
space:
mode:
Diffstat (limited to 'src/pkg/math/hypot_port.go')
-rw-r--r--src/pkg/math/hypot_port.go63
1 files changed, 0 insertions, 63 deletions
diff --git a/src/pkg/math/hypot_port.go b/src/pkg/math/hypot_port.go
deleted file mode 100644
index 27f335ba2..000000000
--- a/src/pkg/math/hypot_port.go
+++ /dev/null
@@ -1,63 +0,0 @@
-// 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
-
-/*
- Hypot -- sqrt(p*p + q*q), but overflows only if the result does.
- See:
- Cleve Moler and Donald Morrison,
- Replacing Square Roots by Pythagorean Sums
- IBM Journal of Research and Development,
- Vol. 27, Number 6, pp. 577-581, Nov. 1983
-*/
-
-// Hypot computes Sqrt(p*p + q*q), taking care to avoid
-// unnecessary overflow and underflow.
-//
-// Special cases are:
-// Hypot(p, q) = +Inf if p or q is infinite
-// Hypot(p, q) = NaN if p or q is NaN
-func hypotGo(p, q float64) float64 {
- // TODO(rsc): Remove manual inlining of IsNaN, IsInf
- // when compiler does it for us
- // special cases
- switch {
- case p < -MaxFloat64 || p > MaxFloat64 || q < -MaxFloat64 || q > MaxFloat64: // IsInf(p, 0) || IsInf(q, 0):
- return Inf(1)
- case p != p || q != q: // IsNaN(p) || IsNaN(q):
- return NaN()
- }
- if p < 0 {
- p = -p
- }
- if q < 0 {
- q = -q
- }
-
- if p < q {
- p, q = q, p
- }
-
- if p == 0 {
- return 0
- }
-
- pfac := p
- q = q / p
- r := q
- p = 1
- for {
- r = r * r
- s := r + 4
- if s == 4 {
- return p * pfac
- }
- r = r / s
- p = p + 2*r*p
- q = q * r
- r = q / p
- }
- panic("unreachable")
-}