Gecko [ 167.86.127.34 ]

Name	Size	Permission
accuracy_string.go	414 B	-rw-r--r--
arith.go	5.68 KB	-rw-r--r--
arith_386.s	4.67 KB	-rw-r--r--
arith_amd64.go	277 B	-rw-r--r--
arith_amd64.s	9.71 KB	-rw-r--r--
arith_arm.s	4.47 KB	-rw-r--r--
arith_arm64.s	9.94 KB	-rw-r--r--
arith_decl.go	707 B	-rw-r--r--
arith_decl_pure.go	1.24 KB	-rw-r--r--
arith_decl_s390x.go	791 B	-rw-r--r--
arith_mips64x.s	917 B	-rw-r--r--
arith_mipsx.s	913 B	-rw-r--r--
arith_ppc64x.s	12.62 KB	-rw-r--r--
arith_s390x.s	29.12 KB	-rw-r--r--
arith_s390x_test.go	1014 B	-rw-r--r--
arith_test.go	12.29 KB	-rw-r--r--
arith_wasm.s	757 B	-rw-r--r--
bits_test.go	5.07 KB	-rw-r--r--
calibrate_test.go	4.63 KB	-rw-r--r--
decimal.go	6.52 KB	-rw-r--r--
decimal_test.go	3.33 KB	-rw-r--r--
doc.go	3.79 KB	-rw-r--r--
example_rat_test.go	1.68 KB	-rw-r--r--
example_test.go	3.94 KB	-rw-r--r--
float.go	44.14 KB	-rw-r--r--
float_test.go	51.94 KB	-rw-r--r--
floatconv.go	8.36 KB	-rw-r--r--
floatconv_test.go	24.28 KB	-rw-r--r--
floatexample_test.go	3.63 KB	-rw-r--r--
floatmarsh.go	3.34 KB	-rw-r--r--
floatmarsh_test.go	3.64 KB	-rw-r--r--
ftoa.go	13.55 KB	-rw-r--r--
gcd_test.go	2.16 KB	-rw-r--r--
hilbert_test.go	2.88 KB	-rw-r--r--
int.go	29.56 KB	-rw-r--r--
int_test.go	51.93 KB	-rw-r--r--
intconv.go	6.68 KB	-rw-r--r--
intconv_test.go	10.01 KB	-rw-r--r--
intmarsh.go	2.09 KB	-rw-r--r--
intmarsh_test.go	2.8 KB	-rw-r--r--
nat.go	33.76 KB	-rw-r--r--
nat_test.go	18.87 KB	-rw-r--r--
natconv.go	14.57 KB	-rw-r--r--
natconv_test.go	16.85 KB	-rw-r--r--
prime.go	10.34 KB	-rw-r--r--
prime_test.go	7.1 KB	-rw-r--r--
rat.go	13.49 KB	-rw-r--r--
rat_test.go	18.54 KB	-rw-r--r--
ratconv.go	9.49 KB	-rw-r--r--
ratconv_test.go	14.96 KB	-rw-r--r--
ratmarsh.go	1.95 KB	-rw-r--r--
ratmarsh_test.go	3.04 KB	-rw-r--r--
roundingmode_string.go	501 B	-rw-r--r--
sqrt.go	3.59 KB	-rw-r--r--
sqrt_test.go	4.81 KB	-rw-r--r--

Code Editor : hilbert_test.go

// Copyright 2009 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.

// A little test program and benchmark for rational arithmetics.
// Computes a Hilbert matrix, its inverse, multiplies them
// and verifies that the product is the identity matrix.

package big

import (
	"fmt"
	"testing"
)

type matrix struct {
	n, m int
	a    []*Rat
}

func (a *matrix) at(i, j int) *Rat {
	if !(0 <= i && i < a.n && 0 <= j && j < a.m) {
		panic("index out of range")
	}
	return a.a[i*a.m+j]
}

func (a *matrix) set(i, j int, x *Rat) {
	if !(0 <= i && i < a.n && 0 <= j && j < a.m) {
		panic("index out of range")
	}
	a.a[i*a.m+j] = x
}

func newMatrix(n, m int) *matrix {
	if !(0 <= n && 0 <= m) {
		panic("illegal matrix")
	}
	a := new(matrix)
	a.n = n
	a.m = m
	a.a = make([]*Rat, n*m)
	return a
}

func newUnit(n int) *matrix {
	a := newMatrix(n, n)
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			x := NewRat(0, 1)
			if i == j {
				x.SetInt64(1)
			}
			a.set(i, j, x)
		}
	}
	return a
}

func newHilbert(n int) *matrix {
	a := newMatrix(n, n)
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			a.set(i, j, NewRat(1, int64(i+j+1)))
		}
	}
	return a
}

func newInverseHilbert(n int) *matrix {
	a := newMatrix(n, n)
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			x1 := new(Rat).SetInt64(int64(i + j + 1))
			x2 := new(Rat).SetInt(new(Int).Binomial(int64(n+i), int64(n-j-1)))
			x3 := new(Rat).SetInt(new(Int).Binomial(int64(n+j), int64(n-i-1)))
			x4 := new(Rat).SetInt(new(Int).Binomial(int64(i+j), int64(i)))

x1.Mul(x1, x2)
			x1.Mul(x1, x3)
			x1.Mul(x1, x4)
			x1.Mul(x1, x4)

if (i+j)&1 != 0 {
				x1.Neg(x1)
			}

a.set(i, j, x1)
		}
	}
	return a
}

func (a *matrix) mul(b *matrix) *matrix {
	if a.m != b.n {
		panic("illegal matrix multiply")
	}
	c := newMatrix(a.n, b.m)
	for i := 0; i < c.n; i++ {
		for j := 0; j < c.m; j++ {
			x := NewRat(0, 1)
			for k := 0; k < a.m; k++ {
				x.Add(x, new(Rat).Mul(a.at(i, k), b.at(k, j)))
			}
			c.set(i, j, x)
		}
	}
	return c
}

func (a *matrix) eql(b *matrix) bool {
	if a.n != b.n || a.m != b.m {
		return false
	}
	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 {
				return false
			}
		}
	}
	return true
}

func (a *matrix) String() string {
	s := ""
	for i := 0; i < a.n; i++ {
		for j := 0; j < a.m; j++ {
			s += fmt.Sprintf("\t%s", a.at(i, j))
		}
		s += "\n"
	}
	return s
}

func doHilbert(t *testing.T, n int) {
	a := newHilbert(n)
	b := newInverseHilbert(n)
	I := newUnit(n)
	ab := a.mul(b)
	if !ab.eql(I) {
		if t == nil {
			panic("Hilbert failed")
		}
		t.Errorf("a   = %s\n", a)
		t.Errorf("b   = %s\n", b)
		t.Errorf("a*b = %s\n", ab)
		t.Errorf("I   = %s\n", I)
	}
}

func TestHilbert(t *testing.T) {
	doHilbert(t, 10)
}

func BenchmarkHilbert(b *testing.B) {
	for i := 0; i < b.N; i++ {
		doHilbert(nil, 10)
	}
}

${this.title}

Code Editor : hilbert_test.go