mirror of git://gcc.gnu.org/git/gcc.git
				
				
				
			
		
			
				
	
	
		
			623 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			623 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
| // Copyright 2010 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.
 | |
| 
 | |
| package big
 | |
| 
 | |
| import (
 | |
| 	"math"
 | |
| 	"testing"
 | |
| )
 | |
| 
 | |
| func TestZeroRat(t *testing.T) {
 | |
| 	var x, y, z Rat
 | |
| 	y.SetFrac64(0, 42)
 | |
| 
 | |
| 	if x.Cmp(&y) != 0 {
 | |
| 		t.Errorf("x and y should be both equal and zero")
 | |
| 	}
 | |
| 
 | |
| 	if s := x.String(); s != "0/1" {
 | |
| 		t.Errorf("got x = %s, want 0/1", s)
 | |
| 	}
 | |
| 
 | |
| 	if s := x.RatString(); s != "0" {
 | |
| 		t.Errorf("got x = %s, want 0", s)
 | |
| 	}
 | |
| 
 | |
| 	z.Add(&x, &y)
 | |
| 	if s := z.RatString(); s != "0" {
 | |
| 		t.Errorf("got x+y = %s, want 0", s)
 | |
| 	}
 | |
| 
 | |
| 	z.Sub(&x, &y)
 | |
| 	if s := z.RatString(); s != "0" {
 | |
| 		t.Errorf("got x-y = %s, want 0", s)
 | |
| 	}
 | |
| 
 | |
| 	z.Mul(&x, &y)
 | |
| 	if s := z.RatString(); s != "0" {
 | |
| 		t.Errorf("got x*y = %s, want 0", s)
 | |
| 	}
 | |
| 
 | |
| 	// check for division by zero
 | |
| 	defer func() {
 | |
| 		if s := recover(); s == nil || s.(string) != "division by zero" {
 | |
| 			panic(s)
 | |
| 		}
 | |
| 	}()
 | |
| 	z.Quo(&x, &y)
 | |
| }
 | |
| 
 | |
| func TestRatSign(t *testing.T) {
 | |
| 	zero := NewRat(0, 1)
 | |
| 	for _, a := range setStringTests {
 | |
| 		x, ok := new(Rat).SetString(a.in)
 | |
| 		if !ok {
 | |
| 			continue
 | |
| 		}
 | |
| 		s := x.Sign()
 | |
| 		e := x.Cmp(zero)
 | |
| 		if s != e {
 | |
| 			t.Errorf("got %d; want %d for z = %v", s, e, &x)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| var ratCmpTests = []struct {
 | |
| 	rat1, rat2 string
 | |
| 	out        int
 | |
| }{
 | |
| 	{"0", "0/1", 0},
 | |
| 	{"1/1", "1", 0},
 | |
| 	{"-1", "-2/2", 0},
 | |
| 	{"1", "0", 1},
 | |
| 	{"0/1", "1/1", -1},
 | |
| 	{"-5/1434770811533343057144", "-5/1434770811533343057145", -1},
 | |
| 	{"49832350382626108453/8964749413", "49832350382626108454/8964749413", -1},
 | |
| 	{"-37414950961700930/7204075375675961", "37414950961700930/7204075375675961", -1},
 | |
| 	{"37414950961700930/7204075375675961", "74829901923401860/14408150751351922", 0},
 | |
| }
 | |
| 
 | |
| func TestRatCmp(t *testing.T) {
 | |
| 	for i, test := range ratCmpTests {
 | |
| 		x, _ := new(Rat).SetString(test.rat1)
 | |
| 		y, _ := new(Rat).SetString(test.rat2)
 | |
| 
 | |
| 		out := x.Cmp(y)
 | |
| 		if out != test.out {
 | |
| 			t.Errorf("#%d got out = %v; want %v", i, out, test.out)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestIsInt(t *testing.T) {
 | |
| 	one := NewInt(1)
 | |
| 	for _, a := range setStringTests {
 | |
| 		x, ok := new(Rat).SetString(a.in)
 | |
| 		if !ok {
 | |
| 			continue
 | |
| 		}
 | |
| 		i := x.IsInt()
 | |
| 		e := x.Denom().Cmp(one) == 0
 | |
| 		if i != e {
 | |
| 			t.Errorf("got IsInt(%v) == %v; want %v", x, i, e)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestRatAbs(t *testing.T) {
 | |
| 	zero := new(Rat)
 | |
| 	for _, a := range setStringTests {
 | |
| 		x, ok := new(Rat).SetString(a.in)
 | |
| 		if !ok {
 | |
| 			continue
 | |
| 		}
 | |
| 		e := new(Rat).Set(x)
 | |
| 		if e.Cmp(zero) < 0 {
 | |
| 			e.Sub(zero, e)
 | |
| 		}
 | |
| 		z := new(Rat).Abs(x)
 | |
| 		if z.Cmp(e) != 0 {
 | |
| 			t.Errorf("got Abs(%v) = %v; want %v", x, z, e)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestRatNeg(t *testing.T) {
 | |
| 	zero := new(Rat)
 | |
| 	for _, a := range setStringTests {
 | |
| 		x, ok := new(Rat).SetString(a.in)
 | |
| 		if !ok {
 | |
| 			continue
 | |
| 		}
 | |
| 		e := new(Rat).Sub(zero, x)
 | |
| 		z := new(Rat).Neg(x)
 | |
| 		if z.Cmp(e) != 0 {
 | |
| 			t.Errorf("got Neg(%v) = %v; want %v", x, z, e)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestRatInv(t *testing.T) {
 | |
| 	zero := new(Rat)
 | |
| 	for _, a := range setStringTests {
 | |
| 		x, ok := new(Rat).SetString(a.in)
 | |
| 		if !ok {
 | |
| 			continue
 | |
| 		}
 | |
| 		if x.Cmp(zero) == 0 {
 | |
| 			continue // avoid division by zero
 | |
| 		}
 | |
| 		e := new(Rat).SetFrac(x.Denom(), x.Num())
 | |
| 		z := new(Rat).Inv(x)
 | |
| 		if z.Cmp(e) != 0 {
 | |
| 			t.Errorf("got Inv(%v) = %v; want %v", x, z, e)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| type ratBinFun func(z, x, y *Rat) *Rat
 | |
| type ratBinArg struct {
 | |
| 	x, y, z string
 | |
| }
 | |
| 
 | |
| func testRatBin(t *testing.T, i int, name string, f ratBinFun, a ratBinArg) {
 | |
| 	x, _ := new(Rat).SetString(a.x)
 | |
| 	y, _ := new(Rat).SetString(a.y)
 | |
| 	z, _ := new(Rat).SetString(a.z)
 | |
| 	out := f(new(Rat), x, y)
 | |
| 
 | |
| 	if out.Cmp(z) != 0 {
 | |
| 		t.Errorf("%s #%d got %s want %s", name, i, out, z)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| var ratBinTests = []struct {
 | |
| 	x, y      string
 | |
| 	sum, prod string
 | |
| }{
 | |
| 	{"0", "0", "0", "0"},
 | |
| 	{"0", "1", "1", "0"},
 | |
| 	{"-1", "0", "-1", "0"},
 | |
| 	{"-1", "1", "0", "-1"},
 | |
| 	{"1", "1", "2", "1"},
 | |
| 	{"1/2", "1/2", "1", "1/4"},
 | |
| 	{"1/4", "1/3", "7/12", "1/12"},
 | |
| 	{"2/5", "-14/3", "-64/15", "-28/15"},
 | |
| 	{"4707/49292519774798173060", "-3367/70976135186689855734", "84058377121001851123459/1749296273614329067191168098769082663020", "-1760941/388732505247628681598037355282018369560"},
 | |
| 	{"-61204110018146728334/3", "-31052192278051565633/2", "-215564796870448153567/6", "950260896245257153059642991192710872711/3"},
 | |
| 	{"-854857841473707320655/4237645934602118692642972629634714039", "-18/31750379913563777419", "-27/133467566250814981", "15387441146526731771790/134546868362786310073779084329032722548987800600710485341"},
 | |
| 	{"618575745270541348005638912139/19198433543745179392300736", "-19948846211000086/637313996471", "27674141753240653/30123979153216", "-6169936206128396568797607742807090270137721977/6117715203873571641674006593837351328"},
 | |
| 	{"-3/26206484091896184128", "5/2848423294177090248", "15310893822118706237/9330894968229805033368778458685147968", "-5/24882386581946146755650075889827061248"},
 | |
| 	{"26946729/330400702820", "41563965/225583428284", "1238218672302860271/4658307703098666660055", "224002580204097/14906584649915733312176"},
 | |
| 	{"-8259900599013409474/7", "-84829337473700364773/56707961321161574960", "-468402123685491748914621885145127724451/396955729248131024720", "350340947706464153265156004876107029701/198477864624065512360"},
 | |
| 	{"575775209696864/1320203974639986246357", "29/712593081308", "410331716733912717985762465/940768218243776489278275419794956", "808/45524274987585732633"},
 | |
| 	{"1786597389946320496771/2066653520653241", "6269770/1992362624741777", "3559549865190272133656109052308126637/4117523232840525481453983149257", "8967230/3296219033"},
 | |
| 	{"-36459180403360509753/32150500941194292113930", "9381566963714/9633539", "301622077145533298008420642898530153/309723104686531919656937098270", "-3784609207827/3426986245"},
 | |
| }
 | |
| 
 | |
| func TestRatBin(t *testing.T) {
 | |
| 	for i, test := range ratBinTests {
 | |
| 		arg := ratBinArg{test.x, test.y, test.sum}
 | |
| 		testRatBin(t, i, "Add", (*Rat).Add, arg)
 | |
| 
 | |
| 		arg = ratBinArg{test.y, test.x, test.sum}
 | |
| 		testRatBin(t, i, "Add symmetric", (*Rat).Add, arg)
 | |
| 
 | |
| 		arg = ratBinArg{test.sum, test.x, test.y}
 | |
| 		testRatBin(t, i, "Sub", (*Rat).Sub, arg)
 | |
| 
 | |
| 		arg = ratBinArg{test.sum, test.y, test.x}
 | |
| 		testRatBin(t, i, "Sub symmetric", (*Rat).Sub, arg)
 | |
| 
 | |
| 		arg = ratBinArg{test.x, test.y, test.prod}
 | |
| 		testRatBin(t, i, "Mul", (*Rat).Mul, arg)
 | |
| 
 | |
| 		arg = ratBinArg{test.y, test.x, test.prod}
 | |
| 		testRatBin(t, i, "Mul symmetric", (*Rat).Mul, arg)
 | |
| 
 | |
| 		if test.x != "0" {
 | |
| 			arg = ratBinArg{test.prod, test.x, test.y}
 | |
| 			testRatBin(t, i, "Quo", (*Rat).Quo, arg)
 | |
| 		}
 | |
| 
 | |
| 		if test.y != "0" {
 | |
| 			arg = ratBinArg{test.prod, test.y, test.x}
 | |
| 			testRatBin(t, i, "Quo symmetric", (*Rat).Quo, arg)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestIssue820(t *testing.T) {
 | |
| 	x := NewRat(3, 1)
 | |
| 	y := NewRat(2, 1)
 | |
| 	z := y.Quo(x, y)
 | |
| 	q := NewRat(3, 2)
 | |
| 	if z.Cmp(q) != 0 {
 | |
| 		t.Errorf("got %s want %s", z, q)
 | |
| 	}
 | |
| 
 | |
| 	y = NewRat(3, 1)
 | |
| 	x = NewRat(2, 1)
 | |
| 	z = y.Quo(x, y)
 | |
| 	q = NewRat(2, 3)
 | |
| 	if z.Cmp(q) != 0 {
 | |
| 		t.Errorf("got %s want %s", z, q)
 | |
| 	}
 | |
| 
 | |
| 	x = NewRat(3, 1)
 | |
| 	z = x.Quo(x, x)
 | |
| 	q = NewRat(3, 3)
 | |
| 	if z.Cmp(q) != 0 {
 | |
| 		t.Errorf("got %s want %s", z, q)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| var setFrac64Tests = []struct {
 | |
| 	a, b int64
 | |
| 	out  string
 | |
| }{
 | |
| 	{0, 1, "0"},
 | |
| 	{0, -1, "0"},
 | |
| 	{1, 1, "1"},
 | |
| 	{-1, 1, "-1"},
 | |
| 	{1, -1, "-1"},
 | |
| 	{-1, -1, "1"},
 | |
| 	{-9223372036854775808, -9223372036854775808, "1"},
 | |
| }
 | |
| 
 | |
| func TestRatSetFrac64Rat(t *testing.T) {
 | |
| 	for i, test := range setFrac64Tests {
 | |
| 		x := new(Rat).SetFrac64(test.a, test.b)
 | |
| 		if x.RatString() != test.out {
 | |
| 			t.Errorf("#%d got %s want %s", i, x.RatString(), test.out)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestIssue2379(t *testing.T) {
 | |
| 	// 1) no aliasing
 | |
| 	q := NewRat(3, 2)
 | |
| 	x := new(Rat)
 | |
| 	x.SetFrac(NewInt(3), NewInt(2))
 | |
| 	if x.Cmp(q) != 0 {
 | |
| 		t.Errorf("1) got %s want %s", x, q)
 | |
| 	}
 | |
| 
 | |
| 	// 2) aliasing of numerator
 | |
| 	x = NewRat(2, 3)
 | |
| 	x.SetFrac(NewInt(3), x.Num())
 | |
| 	if x.Cmp(q) != 0 {
 | |
| 		t.Errorf("2) got %s want %s", x, q)
 | |
| 	}
 | |
| 
 | |
| 	// 3) aliasing of denominator
 | |
| 	x = NewRat(2, 3)
 | |
| 	x.SetFrac(x.Denom(), NewInt(2))
 | |
| 	if x.Cmp(q) != 0 {
 | |
| 		t.Errorf("3) got %s want %s", x, q)
 | |
| 	}
 | |
| 
 | |
| 	// 4) aliasing of numerator and denominator
 | |
| 	x = NewRat(2, 3)
 | |
| 	x.SetFrac(x.Denom(), x.Num())
 | |
| 	if x.Cmp(q) != 0 {
 | |
| 		t.Errorf("4) got %s want %s", x, q)
 | |
| 	}
 | |
| 
 | |
| 	// 5) numerator and denominator are the same
 | |
| 	q = NewRat(1, 1)
 | |
| 	x = new(Rat)
 | |
| 	n := NewInt(7)
 | |
| 	x.SetFrac(n, n)
 | |
| 	if x.Cmp(q) != 0 {
 | |
| 		t.Errorf("5) got %s want %s", x, q)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestIssue3521(t *testing.T) {
 | |
| 	a := new(Int)
 | |
| 	b := new(Int)
 | |
| 	a.SetString("64375784358435883458348587", 0)
 | |
| 	b.SetString("4789759874531", 0)
 | |
| 
 | |
| 	// 0) a raw zero value has 1 as denominator
 | |
| 	zero := new(Rat)
 | |
| 	one := NewInt(1)
 | |
| 	if zero.Denom().Cmp(one) != 0 {
 | |
| 		t.Errorf("0) got %s want %s", zero.Denom(), one)
 | |
| 	}
 | |
| 
 | |
| 	// 1a) a zero value remains zero independent of denominator
 | |
| 	x := new(Rat)
 | |
| 	x.Denom().Set(new(Int).Neg(b))
 | |
| 	if x.Cmp(zero) != 0 {
 | |
| 		t.Errorf("1a) got %s want %s", x, zero)
 | |
| 	}
 | |
| 
 | |
| 	// 1b) a zero value may have a denominator != 0 and != 1
 | |
| 	x.Num().Set(a)
 | |
| 	qab := new(Rat).SetFrac(a, b)
 | |
| 	if x.Cmp(qab) != 0 {
 | |
| 		t.Errorf("1b) got %s want %s", x, qab)
 | |
| 	}
 | |
| 
 | |
| 	// 2a) an integral value becomes a fraction depending on denominator
 | |
| 	x.SetFrac64(10, 2)
 | |
| 	x.Denom().SetInt64(3)
 | |
| 	q53 := NewRat(5, 3)
 | |
| 	if x.Cmp(q53) != 0 {
 | |
| 		t.Errorf("2a) got %s want %s", x, q53)
 | |
| 	}
 | |
| 
 | |
| 	// 2b) an integral value becomes a fraction depending on denominator
 | |
| 	x = NewRat(10, 2)
 | |
| 	x.Denom().SetInt64(3)
 | |
| 	if x.Cmp(q53) != 0 {
 | |
| 		t.Errorf("2b) got %s want %s", x, q53)
 | |
| 	}
 | |
| 
 | |
| 	// 3) changing the numerator/denominator of a Rat changes the Rat
 | |
| 	x.SetFrac(a, b)
 | |
| 	a = x.Num()
 | |
| 	b = x.Denom()
 | |
| 	a.SetInt64(5)
 | |
| 	b.SetInt64(3)
 | |
| 	if x.Cmp(q53) != 0 {
 | |
| 		t.Errorf("3) got %s want %s", x, q53)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestFloat32Distribution(t *testing.T) {
 | |
| 	// Generate a distribution of (sign, mantissa, exp) values
 | |
| 	// broader than the float32 range, and check Rat.Float32()
 | |
| 	// always picks the closest float32 approximation.
 | |
| 	var add = []int64{
 | |
| 		0,
 | |
| 		1,
 | |
| 		3,
 | |
| 		5,
 | |
| 		7,
 | |
| 		9,
 | |
| 		11,
 | |
| 	}
 | |
| 	var winc, einc = uint64(5), 15 // quick test (~60ms on x86-64)
 | |
| 	if *long {
 | |
| 		winc, einc = uint64(1), 1 // soak test (~1.5s on x86-64)
 | |
| 	}
 | |
| 
 | |
| 	for _, sign := range "+-" {
 | |
| 		for _, a := range add {
 | |
| 			for wid := uint64(0); wid < 30; wid += winc {
 | |
| 				b := 1<<wid + a
 | |
| 				if sign == '-' {
 | |
| 					b = -b
 | |
| 				}
 | |
| 				for exp := -150; exp < 150; exp += einc {
 | |
| 					num, den := NewInt(b), NewInt(1)
 | |
| 					if exp > 0 {
 | |
| 						num.Lsh(num, uint(exp))
 | |
| 					} else {
 | |
| 						den.Lsh(den, uint(-exp))
 | |
| 					}
 | |
| 					r := new(Rat).SetFrac(num, den)
 | |
| 					f, _ := r.Float32()
 | |
| 
 | |
| 					if !checkIsBestApprox32(t, f, r) {
 | |
| 						// Append context information.
 | |
| 						t.Errorf("(input was mantissa %#x, exp %d; f = %g (%b); f ~ %g; r = %v)",
 | |
| 							b, exp, f, f, math.Ldexp(float64(b), exp), r)
 | |
| 					}
 | |
| 
 | |
| 					checkNonLossyRoundtrip32(t, f)
 | |
| 				}
 | |
| 			}
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| func TestFloat64Distribution(t *testing.T) {
 | |
| 	// Generate a distribution of (sign, mantissa, exp) values
 | |
| 	// broader than the float64 range, and check Rat.Float64()
 | |
| 	// always picks the closest float64 approximation.
 | |
| 	var add = []int64{
 | |
| 		0,
 | |
| 		1,
 | |
| 		3,
 | |
| 		5,
 | |
| 		7,
 | |
| 		9,
 | |
| 		11,
 | |
| 	}
 | |
| 	var winc, einc = uint64(10), 500 // quick test (~12ms on x86-64)
 | |
| 	if *long {
 | |
| 		winc, einc = uint64(1), 1 // soak test (~75s on x86-64)
 | |
| 	}
 | |
| 
 | |
| 	for _, sign := range "+-" {
 | |
| 		for _, a := range add {
 | |
| 			for wid := uint64(0); wid < 60; wid += winc {
 | |
| 				b := 1<<wid + a
 | |
| 				if sign == '-' {
 | |
| 					b = -b
 | |
| 				}
 | |
| 				for exp := -1100; exp < 1100; exp += einc {
 | |
| 					num, den := NewInt(b), NewInt(1)
 | |
| 					if exp > 0 {
 | |
| 						num.Lsh(num, uint(exp))
 | |
| 					} else {
 | |
| 						den.Lsh(den, uint(-exp))
 | |
| 					}
 | |
| 					r := new(Rat).SetFrac(num, den)
 | |
| 					f, _ := r.Float64()
 | |
| 
 | |
| 					if !checkIsBestApprox64(t, f, r) {
 | |
| 						// Append context information.
 | |
| 						t.Errorf("(input was mantissa %#x, exp %d; f = %g (%b); f ~ %g; r = %v)",
 | |
| 							b, exp, f, f, math.Ldexp(float64(b), exp), r)
 | |
| 					}
 | |
| 
 | |
| 					checkNonLossyRoundtrip64(t, f)
 | |
| 				}
 | |
| 			}
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| // TestSetFloat64NonFinite checks that SetFloat64 of a non-finite value
 | |
| // returns nil.
 | |
| func TestSetFloat64NonFinite(t *testing.T) {
 | |
| 	for _, f := range []float64{math.NaN(), math.Inf(+1), math.Inf(-1)} {
 | |
| 		var r Rat
 | |
| 		if r2 := r.SetFloat64(f); r2 != nil {
 | |
| 			t.Errorf("SetFloat64(%g) was %v, want nil", f, r2)
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| 
 | |
| // checkNonLossyRoundtrip32 checks that a float->Rat->float roundtrip is
 | |
| // non-lossy for finite f.
 | |
| func checkNonLossyRoundtrip32(t *testing.T, f float32) {
 | |
| 	if !isFinite(float64(f)) {
 | |
| 		return
 | |
| 	}
 | |
| 	r := new(Rat).SetFloat64(float64(f))
 | |
| 	if r == nil {
 | |
| 		t.Errorf("Rat.SetFloat64(float64(%g) (%b)) == nil", f, f)
 | |
| 		return
 | |
| 	}
 | |
| 	f2, exact := r.Float32()
 | |
| 	if f != f2 || !exact {
 | |
| 		t.Errorf("Rat.SetFloat64(float64(%g)).Float32() = %g (%b), %v, want %g (%b), %v; delta = %b",
 | |
| 			f, f2, f2, exact, f, f, true, f2-f)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| // checkNonLossyRoundtrip64 checks that a float->Rat->float roundtrip is
 | |
| // non-lossy for finite f.
 | |
| func checkNonLossyRoundtrip64(t *testing.T, f float64) {
 | |
| 	if !isFinite(f) {
 | |
| 		return
 | |
| 	}
 | |
| 	r := new(Rat).SetFloat64(f)
 | |
| 	if r == nil {
 | |
| 		t.Errorf("Rat.SetFloat64(%g (%b)) == nil", f, f)
 | |
| 		return
 | |
| 	}
 | |
| 	f2, exact := r.Float64()
 | |
| 	if f != f2 || !exact {
 | |
| 		t.Errorf("Rat.SetFloat64(%g).Float64() = %g (%b), %v, want %g (%b), %v; delta = %b",
 | |
| 			f, f2, f2, exact, f, f, true, f2-f)
 | |
| 	}
 | |
| }
 | |
| 
 | |
| // delta returns the absolute difference between r and f.
 | |
| func delta(r *Rat, f float64) *Rat {
 | |
| 	d := new(Rat).Sub(r, new(Rat).SetFloat64(f))
 | |
| 	return d.Abs(d)
 | |
| }
 | |
| 
 | |
| // checkIsBestApprox32 checks that f is the best possible float32
 | |
| // approximation of r.
 | |
| // Returns true on success.
 | |
| func checkIsBestApprox32(t *testing.T, f float32, r *Rat) bool {
 | |
| 	if math.Abs(float64(f)) >= math.MaxFloat32 {
 | |
| 		// Cannot check +Inf, -Inf, nor the float next to them (MaxFloat32).
 | |
| 		// But we have tests for these special cases.
 | |
| 		return true
 | |
| 	}
 | |
| 
 | |
| 	// r must be strictly between f0 and f1, the floats bracketing f.
 | |
| 	f0 := math.Nextafter32(f, float32(math.Inf(-1)))
 | |
| 	f1 := math.Nextafter32(f, float32(math.Inf(+1)))
 | |
| 
 | |
| 	// For f to be correct, r must be closer to f than to f0 or f1.
 | |
| 	df := delta(r, float64(f))
 | |
| 	df0 := delta(r, float64(f0))
 | |
| 	df1 := delta(r, float64(f1))
 | |
| 	if df.Cmp(df0) > 0 {
 | |
| 		t.Errorf("Rat(%v).Float32() = %g (%b), but previous float32 %g (%b) is closer", r, f, f, f0, f0)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df1) > 0 {
 | |
| 		t.Errorf("Rat(%v).Float32() = %g (%b), but next float32 %g (%b) is closer", r, f, f, f1, f1)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df0) == 0 && !isEven32(f) {
 | |
| 		t.Errorf("Rat(%v).Float32() = %g (%b); halfway should have rounded to %g (%b) instead", r, f, f, f0, f0)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df1) == 0 && !isEven32(f) {
 | |
| 		t.Errorf("Rat(%v).Float32() = %g (%b); halfway should have rounded to %g (%b) instead", r, f, f, f1, f1)
 | |
| 		return false
 | |
| 	}
 | |
| 	return true
 | |
| }
 | |
| 
 | |
| // checkIsBestApprox64 checks that f is the best possible float64
 | |
| // approximation of r.
 | |
| // Returns true on success.
 | |
| func checkIsBestApprox64(t *testing.T, f float64, r *Rat) bool {
 | |
| 	if math.Abs(f) >= math.MaxFloat64 {
 | |
| 		// Cannot check +Inf, -Inf, nor the float next to them (MaxFloat64).
 | |
| 		// But we have tests for these special cases.
 | |
| 		return true
 | |
| 	}
 | |
| 
 | |
| 	// r must be strictly between f0 and f1, the floats bracketing f.
 | |
| 	f0 := math.Nextafter(f, math.Inf(-1))
 | |
| 	f1 := math.Nextafter(f, math.Inf(+1))
 | |
| 
 | |
| 	// For f to be correct, r must be closer to f than to f0 or f1.
 | |
| 	df := delta(r, f)
 | |
| 	df0 := delta(r, f0)
 | |
| 	df1 := delta(r, f1)
 | |
| 	if df.Cmp(df0) > 0 {
 | |
| 		t.Errorf("Rat(%v).Float64() = %g (%b), but previous float64 %g (%b) is closer", r, f, f, f0, f0)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df1) > 0 {
 | |
| 		t.Errorf("Rat(%v).Float64() = %g (%b), but next float64 %g (%b) is closer", r, f, f, f1, f1)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df0) == 0 && !isEven64(f) {
 | |
| 		t.Errorf("Rat(%v).Float64() = %g (%b); halfway should have rounded to %g (%b) instead", r, f, f, f0, f0)
 | |
| 		return false
 | |
| 	}
 | |
| 	if df.Cmp(df1) == 0 && !isEven64(f) {
 | |
| 		t.Errorf("Rat(%v).Float64() = %g (%b); halfway should have rounded to %g (%b) instead", r, f, f, f1, f1)
 | |
| 		return false
 | |
| 	}
 | |
| 	return true
 | |
| }
 | |
| 
 | |
| func isEven32(f float32) bool { return math.Float32bits(f)&1 == 0 }
 | |
| func isEven64(f float64) bool { return math.Float64bits(f)&1 == 0 }
 | |
| 
 | |
| func TestIsFinite(t *testing.T) {
 | |
| 	finites := []float64{
 | |
| 		1.0 / 3,
 | |
| 		4891559871276714924261e+222,
 | |
| 		math.MaxFloat64,
 | |
| 		math.SmallestNonzeroFloat64,
 | |
| 		-math.MaxFloat64,
 | |
| 		-math.SmallestNonzeroFloat64,
 | |
| 	}
 | |
| 	for _, f := range finites {
 | |
| 		if !isFinite(f) {
 | |
| 			t.Errorf("!IsFinite(%g (%b))", f, f)
 | |
| 		}
 | |
| 	}
 | |
| 	nonfinites := []float64{
 | |
| 		math.NaN(),
 | |
| 		math.Inf(-1),
 | |
| 		math.Inf(+1),
 | |
| 	}
 | |
| 	for _, f := range nonfinites {
 | |
| 		if isFinite(f) {
 | |
| 			t.Errorf("IsFinite(%g, (%b))", f, f)
 | |
| 		}
 | |
| 	}
 | |
| }
 |