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