1// Copyright 2018 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// Disabled for s390x because it uses assembly routines that are not 6// accurate for huge arguments. 7 8// +build !s390x 9 10package math_test 11 12import ( 13 . "math" 14 "testing" 15) 16 17// Inputs to test trig_reduce 18var trigHuge = []float64{ 19 1 << 120, 20 1 << 240, 21 1 << 480, 22 1234567891234567 << 180, 23 1234567891234567 << 300, 24 MaxFloat64, 25} 26 27// Results for trigHuge[i] calculated with https://github.com/robpike/ivy 28// using 4096 bits of working precision. Values requiring less than 29// 102 decimal digits (1 << 120, 1 << 240, 1 << 480, 1234567891234567 << 180) 30// were confirmed via https://keisan.casio.com/ 31var cosHuge = []float64{ 32 -0.92587902285483787, 33 0.93601042593353793, 34 -0.28282777640193788, 35 -0.14616431394103619, 36 -0.79456058210671406, 37 -0.99998768942655994, 38} 39 40var sinHuge = []float64{ 41 0.37782010936075202, 42 -0.35197227524865778, 43 0.95917070894368716, 44 0.98926032637023618, 45 -0.60718488235646949, 46 0.00496195478918406, 47} 48 49var tanHuge = []float64{ 50 -0.40806638884180424, 51 -0.37603456702698076, 52 -3.39135965054779932, 53 -6.76813854009065030, 54 0.76417695016604922, 55 -0.00496201587444489, 56} 57 58// Check that trig values of huge angles return accurate results. 59// This confirms that argument reduction works for very large values 60// up to MaxFloat64. 61func TestHugeCos(t *testing.T) { 62 for i := 0; i < len(trigHuge); i++ { 63 f1 := cosHuge[i] 64 f2 := Cos(trigHuge[i]) 65 if !close(f1, f2) { 66 t.Errorf("Cos(%g) = %g, want %g", trigHuge[i], f2, f1) 67 } 68 } 69} 70 71func TestHugeSin(t *testing.T) { 72 for i := 0; i < len(trigHuge); i++ { 73 f1 := sinHuge[i] 74 f2 := Sin(trigHuge[i]) 75 if !close(f1, f2) { 76 t.Errorf("Sin(%g) = %g, want %g", trigHuge[i], f2, f1) 77 } 78 } 79} 80 81func TestHugeSinCos(t *testing.T) { 82 for i := 0; i < len(trigHuge); i++ { 83 f1, g1 := sinHuge[i], cosHuge[i] 84 f2, g2 := Sincos(trigHuge[i]) 85 if !close(f1, f2) || !close(g1, g2) { 86 t.Errorf("Sincos(%g) = %g, %g, want %g, %g", trigHuge[i], f2, g2, f1, g1) 87 } 88 } 89} 90 91func TestHugeTan(t *testing.T) { 92 for i := 0; i < len(trigHuge); i++ { 93 f1 := tanHuge[i] 94 f2 := Tan(trigHuge[i]) 95 if !close(f1, f2) { 96 t.Errorf("Tan(%g) = %g, want %g", trigHuge[i], f2, f1) 97 } 98 } 99} 100