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hilbert now runs.

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it's 25% faster and runs with 40% less memory allocation than before

R=rsc
DELTA=20  (15 added, 0 deleted, 5 changed)
OCL=21690
CL=21690
This commit is contained in:
Rob Pike 2008-12-20 18:15:34 -08:00
parent 9ccf39bd68
commit eb32228627
2 changed files with 20 additions and 5 deletions
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5
src/lib/bignum.go
View File

@ -793,7 +793,10 @@ export func Fact(n uint) Natural {
export func Binomial(n, k uint) Natural {
return MulRange(n-k+1, n).Div(MulRange(1, k));
//BUG return MulRange(n-k+1, n).Div(MulRange(1, k));
x := MulRange(n-k+1, n);
y := MulRange(1, k);
return x.Div(y);
}

20
test/hilbert.go
View File

@ -82,7 +82,7 @@ func NewHilbert(n int) *Matrix {
}
func MakeRat(x *Big.Natural) *Big.Rational {
func MakeRat(x Big.Natural) *Big.Rational {
return Big.MakeRat(Big.MakeInt(false, x), Big.Nat(1));
}
@ -100,7 +100,12 @@ func NewInverseHilbert(n int) *Matrix {
x3 := MakeRat(Big.Binomial(uint(n+j), uint(n-i-1)));
x4 := MakeRat(Big.Binomial(uint(i+j), uint(i)));
x4 = x4.Mul(x4);
a.set(i, j, x0.Mul(x1).Mul(x2).Mul(x3).Mul(x4));
// BUG a.set(i, j, x0.Mul(x1).Mul(x2).Mul(x3).Mul(x4));
y1 := x0.Mul(x1);
y2 := y1.Mul(x2);
y3 := y2.Mul(x3);
y4 := y3.Mul(x4);
a.set(i, j, y4);
}
}
return a;
@ -114,7 +119,11 @@ func (a *Matrix) Mul(b *Matrix) *Matrix {
for j := 0; j < c.m; j++ {
x := Zero;
for k := 0; k < a.m; k++ {
x = x.Add(a.at(i, k).Mul(b.at(k, j)));
//BUG x = x.Add(a.at(i, k).Mul(b.at(k, j)));
a1 := a.at(i, k);
b1 := b.at(k, j);
a2 := a1.Mul(b1);
x = x.Add(a2);
}
c.set(i, j, x);
}
@ -129,7 +138,10 @@ func (a *Matrix) Eql(b *Matrix) bool {
}
for i := 0; i < a.n; i++ {
for j := 0; j < a.m; j++ {
if a.at(i, j).Cmp(b.at(i,j)) != 0 {
// BUG if a.at(i, j).Cmp(b.at(i,j)) != 0 {
a1 := a.at(i, j);
b1 := b.at(i,j);
if a1.Cmp(b1) != 0 {
return false;
}
}