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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) } } }