1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // A copy of Sqrt tests from the math package to test the 6 // purely integer arithmetic implementation in sqrt.go. 7 8 package runtime_test 9 10 import ( 11 "math" 12 "runtime" 13 "testing" 14 ) 15 16 func SqrtRT(x float64) float64 { 17 return math.Float64frombits(runtime.Sqrt(math.Float64bits(x))) 18 } 19 20 func TestSqrt(t *testing.T) { 21 for i := 0; i < len(vf); i++ { 22 a := math.Abs(vf[i]) 23 if f := SqrtRT(a); sqrt[i] != f { 24 t.Errorf("Sqrt(%g) = %g, want %g", a, f, sqrt[i]) 25 } 26 } 27 for i := 0; i < len(vfsqrtSC); i++ { 28 if f := SqrtRT(vfsqrtSC[i]); !alike(sqrtSC[i], f) { 29 t.Errorf("Sqrt(%g) = %g, want %g", vfsqrtSC[i], f, sqrtSC[i]) 30 } 31 } 32 } 33 34 func alike(a, b float64) bool { 35 switch { 36 case math.IsNaN(a) && math.IsNaN(b): 37 return true 38 case a == b: 39 return math.Signbit(a) == math.Signbit(b) 40 } 41 return false 42 } 43 44 var vf = []float64{ 45 4.9790119248836735e+00, 46 7.7388724745781045e+00, 47 -2.7688005719200159e-01, 48 -5.0106036182710749e+00, 49 9.6362937071984173e+00, 50 2.9263772392439646e+00, 51 5.2290834314593066e+00, 52 2.7279399104360102e+00, 53 1.8253080916808550e+00, 54 -8.6859247685756013e+00, 55 } 56 57 var sqrt = []float64{ 58 2.2313699659365484748756904e+00, 59 2.7818829009464263511285458e+00, 60 5.2619393496314796848143251e-01, 61 2.2384377628763938724244104e+00, 62 3.1042380236055381099288487e+00, 63 1.7106657298385224403917771e+00, 64 2.286718922705479046148059e+00, 65 1.6516476350711159636222979e+00, 66 1.3510396336454586262419247e+00, 67 2.9471892997524949215723329e+00, 68 } 69 70 var vfsqrtSC = []float64{ 71 math.Inf(-1), 72 -math.Pi, 73 math.Copysign(0, -1), 74 0, 75 math.Inf(1), 76 math.NaN(), 77 } 78 var sqrtSC = []float64{ 79 math.NaN(), 80 math.NaN(), 81 math.Copysign(0, -1), 82 0, 83 math.Inf(1), 84 math.NaN(), 85 } 86
