diff options
| -rw-r--r-- | src/pkg/big/rat.go | 8 | ||||
| -rw-r--r-- | src/pkg/big/rat_test.go | 26 |
2 files changed, 31 insertions, 3 deletions
diff --git a/src/pkg/big/rat.go b/src/pkg/big/rat.go index f35df4b46..ddd858d5c 100644 --- a/src/pkg/big/rat.go +++ b/src/pkg/big/rat.go @@ -160,9 +160,11 @@ func (z *Rat) Quo(x, y *Rat) *Rat { if len(y.a.abs) == 0 { panic("division by zero") } - z.a.abs = z.a.abs.mul(x.a.abs, y.b) - z.b = z.b.mul(x.b, y.a.abs) - z.a.neg = x.a.neg != y.a.neg + a := mulNat(&x.a, y.b) + b := mulNat(&y.a, x.b) + z.a.abs = a.abs + z.b = b.abs + z.a.neg = a.neg != b.neg return z.norm() } diff --git a/src/pkg/big/rat_test.go b/src/pkg/big/rat_test.go index 0a7797613..2379cc0d5 100644 --- a/src/pkg/big/rat_test.go +++ b/src/pkg/big/rat_test.go @@ -175,3 +175,29 @@ func TestRatBin(t *testing.T) { } } } + + +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) + } +} |