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- // 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) the denominator of an (uninitialized) zero value is not shared with the value
- s := &zero.b
- d := zero.Denom()
- if d == s {
- t.Errorf("1a) got %s (%p) == %s (%p) want different *Int values", d, d, s, s)
- }
- // 1b) the denominator of an (uninitialized) value is a new 1 each time
- d1 := zero.Denom()
- d2 := zero.Denom()
- if d1 == d2 {
- t.Errorf("1b) got %s (%p) == %s (%p) want different *Int values", d1, d1, d2, d2)
- }
- // 1c) the denominator of an initialized zero value is shared with the value
- x := new(Rat)
- x.Set(x) // initialize x (any operation that sets x explicitly will do)
- s = &x.b
- d = x.Denom()
- if d != s {
- t.Errorf("1c) got %s (%p) != %s (%p) want identical *Int values", d, d, s, s)
- }
- // 1d) a zero value remains zero independent of denominator
- x.Denom().Set(new(Int).Neg(b))
- if x.Cmp(zero) != 0 {
- t.Errorf("1d) got %s want %s", x, zero)
- }
- // 1e) 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("1e) 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)
- }
- }
- }
- func TestRatSetInt64(t *testing.T) {
- var testCases = []int64{
- 0,
- 1,
- -1,
- 12345,
- -98765,
- math.MaxInt64,
- math.MinInt64,
- }
- var r = new(Rat)
- for i, want := range testCases {
- r.SetInt64(want)
- if !r.IsInt() {
- t.Errorf("#%d: Rat.SetInt64(%d) is not an integer", i, want)
- }
- num := r.Num()
- if !num.IsInt64() {
- t.Errorf("#%d: Rat.SetInt64(%d) numerator is not an int64", i, want)
- }
- got := num.Int64()
- if got != want {
- t.Errorf("#%d: Rat.SetInt64(%d) = %d, but expected %d", i, want, got, want)
- }
- }
- }
- func TestRatSetUint64(t *testing.T) {
- var testCases = []uint64{
- 0,
- 1,
- 12345,
- ^uint64(0),
- }
- var r = new(Rat)
- for i, want := range testCases {
- r.SetUint64(want)
- if !r.IsInt() {
- t.Errorf("#%d: Rat.SetUint64(%d) is not an integer", i, want)
- }
- num := r.Num()
- if !num.IsUint64() {
- t.Errorf("#%d: Rat.SetUint64(%d) numerator is not a uint64", i, want)
- }
- got := num.Uint64()
- if got != want {
- t.Errorf("#%d: Rat.SetUint64(%d) = %d, but expected %d", i, want, got, want)
- }
- }
- }
- func BenchmarkRatCmp(b *testing.B) {
- x, y := NewRat(4, 1), NewRat(7, 2)
- for i := 0; i < b.N; i++ {
- x.Cmp(y)
- }
- }
- // TestIssue34919 verifies that a Rat's denominator is not modified
- // when simply accessing the Rat value.
- func TestIssue34919(t *testing.T) {
- for _, acc := range []struct {
- name string
- f func(*Rat)
- }{
- {"Float32", func(x *Rat) { x.Float32() }},
- {"Float64", func(x *Rat) { x.Float64() }},
- {"Inv", func(x *Rat) { new(Rat).Inv(x) }},
- {"Sign", func(x *Rat) { x.Sign() }},
- {"IsInt", func(x *Rat) { x.IsInt() }},
- {"Num", func(x *Rat) { x.Num() }},
- // {"Denom", func(x *Rat) { x.Denom() }}, TODO(gri) should we change the API? See issue #33792.
- } {
- // A denominator of length 0 is interpreted as 1. Make sure that
- // "materialization" of the denominator doesn't lead to setting
- // the underlying array element 0 to 1.
- r := &Rat{Int{abs: nat{991}}, Int{abs: make(nat, 0, 1)}}
- acc.f(r)
- if d := r.b.abs[:1][0]; d != 0 {
- t.Errorf("%s modified denominator: got %d, want 0", acc.name, d)
- }
- }
- }
- func TestDenomRace(t *testing.T) {
- x := NewRat(1, 2)
- const N = 3
- c := make(chan bool, N)
- for i := 0; i < N; i++ {
- go func() {
- // Denom (also used by Float.SetRat) used to mutate x unnecessarily,
- // provoking race reports when run in the race detector.
- x.Denom()
- new(Float).SetRat(x)
- c <- true
- }()
- }
- for i := 0; i < N; i++ {
- <-c
- }
- }
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