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| // Copyright 2018 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.
|
| // Disabled for s390x because it uses assembly routines that are not
| // accurate for huge arguments.
|
| // +build !s390x
|
| package math_test
|
| import (
| . "math"
| "testing"
| )
|
| // Inputs to test trig_reduce
| var trigHuge = []float64{
| 1 << 120,
| 1 << 240,
| 1 << 480,
| 1234567891234567 << 180,
| 1234567891234567 << 300,
| MaxFloat64,
| }
|
| // Results for trigHuge[i] calculated with https://github.com/robpike/ivy
| // using 4096 bits of working precision. Values requiring less than
| // 102 decimal digits (1 << 120, 1 << 240, 1 << 480, 1234567891234567 << 180)
| // were confirmed via https://keisan.casio.com/
| var cosHuge = []float64{
| -0.92587902285483787,
| 0.93601042593353793,
| -0.28282777640193788,
| -0.14616431394103619,
| -0.79456058210671406,
| -0.99998768942655994,
| }
|
| var sinHuge = []float64{
| 0.37782010936075202,
| -0.35197227524865778,
| 0.95917070894368716,
| 0.98926032637023618,
| -0.60718488235646949,
| 0.00496195478918406,
| }
|
| var tanHuge = []float64{
| -0.40806638884180424,
| -0.37603456702698076,
| -3.39135965054779932,
| -6.76813854009065030,
| 0.76417695016604922,
| -0.00496201587444489,
| }
|
| // Check that trig values of huge angles return accurate results.
| // This confirms that argument reduction works for very large values
| // up to MaxFloat64.
| func TestHugeCos(t *testing.T) {
| for i := 0; i < len(trigHuge); i++ {
| f1 := cosHuge[i]
| f2 := Cos(trigHuge[i])
| if !close(f1, f2) {
| t.Errorf("Cos(%g) = %g, want %g", trigHuge[i], f2, f1)
| }
| }
| }
|
| func TestHugeSin(t *testing.T) {
| for i := 0; i < len(trigHuge); i++ {
| f1 := sinHuge[i]
| f2 := Sin(trigHuge[i])
| if !close(f1, f2) {
| t.Errorf("Sin(%g) = %g, want %g", trigHuge[i], f2, f1)
| }
| }
| }
|
| func TestHugeSinCos(t *testing.T) {
| for i := 0; i < len(trigHuge); i++ {
| f1, g1 := sinHuge[i], cosHuge[i]
| f2, g2 := Sincos(trigHuge[i])
| if !close(f1, f2) || !close(g1, g2) {
| t.Errorf("Sincos(%g) = %g, %g, want %g, %g", trigHuge[i], f2, g2, f1, g1)
| }
| }
| }
|
| func TestHugeTan(t *testing.T) {
| for i := 0; i < len(trigHuge); i++ {
| f1 := tanHuge[i]
| f2 := Tan(trigHuge[i])
| if !close(f1, f2) {
| t.Errorf("Tan(%g) = %g, want %g", trigHuge[i], f2, f1)
| }
| }
| }
|
|
