floats/expm1_128_test.go at main · shogo82148/floats · GitHub

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package floats

import (
	"math"
	"testing"
)

func TestFloat128_Expm1(t *testing.T) {
	tests := []struct {
		x    Float128
		want string
	}{
		{exact128(-0x1p24), "-1"},
		{exact128(-1), "-0.6321205588285576784044762298385391325541888689682321654921631983025385042551001966"},
		{exact128(-0x1p-24), "-5.96046429990338208927884783441062475300635261015299376854993634082159971776677455E-8"},
		{exact128(-0x1p-25), "-2.980232194360610706156728457749074378475050447510024450735796644104588740223894263E-8"},
		{exact128(0), "0"},
		{exact128(0x1p-25), "2.980232283178452676169258265480484667505915170034780254106203474178642385993634061E-8"},
		{exact128(0x1p-24), "5.960464655174749969329045951426788010322030160311252070356772304688050582038483484E-8"},
		{exact128(0.25), "0.2840254166877414840734205680624364583362808652814630892175072968722077658672380028"},
		{exact128(1), "1.718281828459045235360287471352662497757247093699959574966967627724076630353547595"},
		{exact128(10), "22025.46579480671651695790064528424436635351261855678107423542635522520281857079258"},
		{exact128(36), "4311231547115194.227113422292856925390788863616780347730770167843912372047055558563"},
		{exact128(62), "843835666874145448907332947.0373117960080692679667410404618178186988225756502453424"},
	}

	for _, tt := range tests {
		got := tt.x.Expm1()
		if !close128(got, tt.want) {
			t.Errorf("Expm1(%v) = %v; want %v", tt.x, got, tt.want)
		}
	}

	strictTests := []struct {
		x    Float128
		want Float128
	}{
		{exact128(0), exact128(0)},
		{exact128(math.Copysign(0, -1)), exact128(math.Copysign(0, -1))},

		// special cases
		{exact128(math.Inf(1)), exact128(math.Inf(1))},
		{exact128(math.Inf(-1)), exact128(-1)},
		{exact128(math.NaN()), exact128(math.NaN())},
	}

	for _, tt := range strictTests {
		got := tt.x.Expm1()
		if !eq128(got, tt.want) {
			t.Errorf("Expm1(%v) = %v; want %v", tt.x, got, tt.want)
		}
	}
}