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