Example #1
0
func r32() *mathutil.FC32 {
	r, err := mathutil.NewFC32(math.MinInt32, math.MaxInt32, true)
	if err != nil {
		panic(err)
	}

	return r
}
Example #2
0
func TestModPow2(t *testing.T) {
	const N = 1e3
	data := []struct{ e, m uint32 }{
		// e == 0 -> x == 0
		{0, 2},
		{0, 3},
		{0, 4},

		{1, 2},
		{1, 3},
		{1, 4},
		{1, 5},

		{2, 2},
		{2, 3},
		{2, 4},
		{2, 5},

		{3, 2},
		{3, 3},
		{3, 4},
		{3, 5},
		{3, 6},
		{3, 7},
		{3, 8},
		{3, 9},

		{4, 2},
		{4, 3},
		{4, 4},
		{4, 5},
		{4, 6},
		{4, 7},
		{4, 8},
		{4, 9},
	}

	var got big.Int
	f := func(e, m uint32) {
		x := ModPow2(e, m)
		exp := ModPow(2, e, m)
		got.SetInt64(0)
		got.SetBit(&got, int(x), 1)
		if got.Cmp(exp) != 0 {
			t.Fatalf("\ne %d, m %d\ng: %s\ne: %s", e, m, &got, exp)
		}
	}

	for _, v := range data {
		f(v.e, v.m)
	}

	rg, _ := mathutil.NewFC32(2, 1<<10, true)
	for i := 0; i < N; i++ {
		f(uint32(rg.Next()), uint32(rg.Next()))
	}
}
Example #3
0
func TestMod(t *testing.T) {
	const N = 1e4
	data := []struct {
		mod, n int64
		exp    uint32
	}{
		{0, 0x00, 3},
		{1, 0x01, 3},
		{3, 0x03, 3},
		{0, 0x07, 3},
		{1, 0x0f, 3},
		{3, 0x1f, 3},
		{0, 0x3f, 3},
		{1, 0x7f, 3},
		{3, 0xff, 3},
		{0, 0x1ff, 3},
	}

	var mod, n big.Int
	for _, v := range data {
		n.SetInt64(v.n)
		p := Mod(&mod, &n, v.exp)
		if p != &mod {
			t.Fatal(p)
		}

		if g, e := mod.Int64(), v.mod; g != e {
			t.Fatal(v.n, v.exp, g, e)
		}
	}

	f := func(in int64, exp uint32) {
		n.SetInt64(in)
		mod.Mod(&n, New(exp))
		e := mod.Int64()
		Mod(&mod, &n, exp)
		g := mod.Int64()
		if g != e {
			t.Fatal(in, exp, g, e)
		}
	}

	r32, _ := mathutil.NewFC32(1, 1e6, true)
	r64, _ := mathutil.NewFCBig(_0, big.NewInt(math.MaxInt64), true)
	for i := 0; i < N; i++ {
		f(r64.Next().Int64(), uint32(r32.Next()))
	}
}
Example #4
0
func TestModPow(t *testing.T) {
	const N = 2e2
	data := []struct{ b, e, m, r uint32 }{
		{0, 1, 1, 0},
		{0, 2, 1, 0},
		{0, 3, 1, 0},

		{1, 0, 1, 0},
		{1, 1, 1, 0},
		{1, 2, 1, 0},
		{1, 3, 1, 0},

		{2, 0, 1, 0},
		{2, 1, 1, 0},
		{2, 2, 1, 0},
		{2, 3, 1, 0},

		{2, 3, 4, 8},
		{2, 3, 5, 4},
		{2, 4, 3, 1},
		{3, 3, 3, 3},
		{3, 4, 5, 30},
	}

	f := func(b, e, m uint32, expect *big.Int) {
		got := ModPow(b, e, m)
		if got.Cmp(expect) != 0 {
			t.Fatal(b, e, m, got, expect)
		}
	}

	var r big.Int
	for _, v := range data {
		r.SetInt64(int64(v.r))
		f(v.b, v.e, v.m, &r)
	}

	rg, _ := mathutil.NewFC32(2, 1<<10, true)
	var bb big.Int
	for i := 0; i < N; i++ {
		b, e, m := uint32(rg.Next()), uint32(rg.Next()), uint32(rg.Next())
		bb.SetInt64(int64(b))
		f(b, e, m, mathutil.ModPowBigInt(&bb, New(e), New(m)))
	}
}
Example #5
0
// $ go run example2.go # view rand.png and rnd.png by your favorite pic viewer
//
// see http://www.boallen.com/random-numbers.html
func main() {
	sqr := image.Rect(0, 0, 511, 511)
	r, err := mathutil.NewFC32(math.MinInt32, math.MaxInt32, true)
	if err != nil {
		log.Fatal("NewFC32", err)
	}

	img := image.NewGray(sqr)
	for y := 0; y < 512; y++ {
		for x := 0; x < 512; x++ {
			if r.Next()&1 != 0 {
				img.Set(x, y, image.White)
			}
		}
	}
	buf := bytes.NewBuffer(nil)
	if err := png.Encode(buf, img); err != nil {
		log.Fatal("Encode rnd.png ", err)
	}

	if err := ioutil.WriteFile("rnd.png", buf.Bytes(), 0666); err != nil {
		log.Fatal("ioutil.WriteFile/rnd.png ", err)
	}

	r2 := rand.New(rand.NewSource(0))
	img = image.NewGray(sqr)
	for y := 0; y < 512; y++ {
		for x := 0; x < 512; x++ {
			if r2.Int()&1 != 0 {
				img.Set(x, y, image.White)
			}
		}
	}
	buf = bytes.NewBuffer(nil)
	if err := png.Encode(buf, img); err != nil {
		log.Fatal("Encode rand.png ", err)
	}

	if err := ioutil.WriteFile("rand.png", buf.Bytes(), 0666); err != nil {
		log.Fatal("ioutil.WriteFile/rand.png ", err)
	}
}
Example #6
0
/*

$ # Usage e.g.:
$ go run example.go -max 1024 > mathutil.dat # generate 1kB of "random" data

*/
func main() {
	r, err := mathutil.NewFC32(math.MinInt32, math.MaxInt32, true)
	if err != nil {
		log.Fatal(err)
	}

	var mflag uint64
	flag.Uint64Var(&mflag, "max", 0, "limit output to max bytes")
	flag.Parse()
	stdout := bufio.NewWriter(os.Stdout)
	if mflag != 0 {
		for i := uint64(0); i < mflag; i++ {
			if err := stdout.WriteByte(byte(r.Next())); err != nil {
				log.Fatal(err)
			}
		}
		stdout.Flush()
		return
	}

	for stdout.WriteByte(byte(r.Next())) == nil {
	}
}