math: Atan2 special cases and tests; atan2_386
Added special cases, tests and benchmarks for Atan2;
added 386 FPU version of Atan2.
R=rsc
CC=golang-dev
https://golang.org/cl/201068
diff --git a/src/pkg/math/all_test.go b/src/pkg/math/all_test.go
index c0ac152..184d045 100644
--- a/src/pkg/math/all_test.go
+++ b/src/pkg/math/all_test.go
@@ -100,6 +100,18 @@
1.8459947964298794318714228e-01,
-1.3273186910532645867272502e+00,
}
+var atan2 = []float64{
+ 1.1088291730037004444527075e+00,
+ 9.1218183188715804018797795e-01,
+ 1.5984772603216203736068915e+00,
+ 2.0352918654092086637227327e+00,
+ 8.0391819139044720267356014e-01,
+ 1.2861075249894661588866752e+00,
+ 1.0889904479131695712182587e+00,
+ 1.3044821793397925293797357e+00,
+ 1.3902530903455392306872261e+00,
+ 2.2859857424479142655411058e+00,
+}
var ceil = []float64{
5.0000000000000000e+00,
8.0000000000000000e+00,
@@ -427,6 +439,64 @@
NaN(),
NaN(),
}
+var vfatan2SC = [][2]float64{
+ [2]float64{Inf(-1), Inf(-1)},
+ [2]float64{Inf(-1), -Pi},
+ [2]float64{Inf(-1), 0},
+ [2]float64{Inf(-1), +Pi},
+ [2]float64{Inf(-1), Inf(1)},
+ [2]float64{Inf(-1), NaN()},
+ [2]float64{-Pi, Inf(-1)},
+ [2]float64{-Pi, 0},
+ [2]float64{-Pi, Inf(1)},
+ [2]float64{-Pi, NaN()},
+ [2]float64{0, Inf(-1)},
+ [2]float64{0, -Pi},
+ [2]float64{0, 0},
+ [2]float64{0, +Pi},
+ [2]float64{0, Inf(1)},
+ [2]float64{0, NaN()},
+ [2]float64{+Pi, Inf(-1)},
+ [2]float64{+Pi, 0},
+ [2]float64{+Pi, Inf(1)},
+ [2]float64{+Pi, NaN()},
+ [2]float64{Inf(1), Inf(-1)},
+ [2]float64{Inf(1), -Pi},
+ [2]float64{Inf(1), 0},
+ [2]float64{Inf(1), +Pi},
+ [2]float64{Inf(1), Inf(1)},
+ [2]float64{Inf(1), NaN()},
+ [2]float64{NaN(), NaN()},
+}
+var atan2SC = []float64{
+ -3 * Pi / 4,
+ -Pi / 2,
+ -Pi / 2,
+ -Pi / 2,
+ -Pi / 4,
+ NaN(),
+ -Pi,
+ -Pi / 2,
+ -0,
+ NaN(),
+ Pi,
+ Pi,
+ 0,
+ 0,
+ 0,
+ NaN(),
+ Pi,
+ Pi / 2,
+ 0,
+ NaN(),
+ 3 * Pi / 4,
+ Pi / 2,
+ Pi / 2,
+ Pi / 2,
+ Pi / 4,
+ NaN(),
+ NaN(),
+}
var vfceilSC = []float64{
Inf(-1),
@@ -851,6 +921,19 @@
}
}
+func TestAtan2(t *testing.T) {
+ for i := 0; i < len(vf); i++ {
+ if f := Atan2(10, vf[i]); !veryclose(atan2[i], f) {
+ t.Errorf("Atan2(10, %g) = %g, want %g\n", vf[i], f, atan2[i])
+ }
+ }
+ for i := 0; i < len(vfatan2SC); i++ {
+ if f := Atan2(vfatan2SC[i][0], vfatan2SC[i][1]); !alike(atan2SC[i], f) {
+ t.Errorf("Atan2(%g, %g) = %g, want %g\n", vfatan2SC[i][0], vfatan2SC[i][1], f, atan2SC[i])
+ }
+ }
+}
+
func TestCeil(t *testing.T) {
for i := 0; i < len(vf); i++ {
if f := Ceil(vf[i]); ceil[i] != f {
@@ -1254,6 +1337,12 @@
}
}
+func BenchmarkAtan2(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ Atan2(.5, 1)
+ }
+}
+
func BenchmarkCeil(b *testing.B) {
for i := 0; i < b.N; i++ {
Ceil(.5)
