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package dict
import (
"math/big"
"math/rand"
"testing"
"time"
"github.com/mmcloughlin/addchain"
"github.com/mmcloughlin/addchain/alg/algtest"
"github.com/mmcloughlin/addchain/alg/contfrac"
"github.com/mmcloughlin/addchain/internal/bigint"
"github.com/mmcloughlin/addchain/internal/bigints"
"github.com/mmcloughlin/addchain/internal/test"
)
func TestDecomposersRandom(t *testing.T) {
ds := []Decomposer{
FixedWindow{K: 2},
FixedWindow{K: 11},
FixedWindow{K: 16},
SlidingWindow{K: 2},
SlidingWindow{K: 7},
SlidingWindow{K: 12},
RunLength{T: 0},
RunLength{T: 1},
RunLength{T: 3},
RunLength{T: 7},
Hybrid{K: 4, T: 7},
Hybrid{K: 3, T: 0},
}
r := rand.New(rand.NewSource(time.Now().UnixNano()))
for _, d := range ds {
d := d
t.Run(d.String(), test.Trials(func(t *testing.T) bool {
n := bigint.RandBits(r, 256)
got := d.Decompose(n)
if !bigint.Equal(got.Int(), n) {
t.Log(got)
t.Fatalf("got %v expect %v", got.Int(), n)
}
return true
}))
}
}
func TestFixedWindow(t *testing.T) {
n := big.NewInt(0xbeef0 << 3)
f := FixedWindow{K: 4}
got := f.Decompose(n)
expect := Sum{
{D: big.NewInt(0xf), E: 7},
{D: big.NewInt(0xe), E: 11},
{D: big.NewInt(0xe), E: 15},
{D: big.NewInt(0xb), E: 19},
}
if !SumEquals(got, expect) {
t.Fatalf("got %v expect %v", got, expect)
}
}
func TestSlidingWindow(t *testing.T) {
n := big.NewInt(0xf143)
f := SlidingWindow{K: 4}
got := f.Decompose(n)
expect := Sum{
{D: big.NewInt(0x3), E: 0},
{D: big.NewInt(0x5), E: 6},
{D: big.NewInt(0xf), E: 12},
}
if !SumEquals(got, expect) {
t.Fatalf("got %v expect %v", got, expect)
}
}
func TestRunLength(t *testing.T) {
cases := []struct {
T uint
X int64
Expect Sum
}{
{
T: 4,
X: 0xff,
Expect: Sum{
{D: big.NewInt(0xf), E: 0},
{D: big.NewInt(0xf), E: 4},
},
},
{
T: 0,
X: 0xff,
Expect: Sum{
{D: big.NewInt(0xff), E: 0},
},
},
{
T: 4,
X: 0xf0f0,
Expect: Sum{
{D: big.NewInt(0xf), E: 4},
{D: big.NewInt(0xf), E: 12},
},
},
{
T: 0,
X: 0xf0f0,
Expect: Sum{
{D: big.NewInt(0xf), E: 4},
{D: big.NewInt(0xf), E: 12},
},
},
{
T: 3,
X: 0xff,
Expect: Sum{
{D: big.NewInt(0x3), E: 0},
{D: big.NewInt(0x7), E: 2},
{D: big.NewInt(0x7), E: 5},
},
},
}
for _, c := range cases {
d := RunLength{T: c.T}
if got := d.Decompose(big.NewInt(c.X)); !SumEquals(got, c.Expect) {
t.Fatalf("Decompose(%#x) = %v; expect %v", c.X, got, c.Expect)
}
}
}
func TestHybrid(t *testing.T) {
n := bigint.MustBinary("11111111_11111111_000_111_000000_1_0_111111_0_11_0")
f := Hybrid{K: 4, T: 8}
got := f.Decompose(n)
expect := Sum{
{D: big.NewInt(0x3), E: 1},
{D: big.NewInt(0x3f), E: 4},
{D: big.NewInt(0x1), E: 11},
{D: big.NewInt(0x7), E: 18},
{D: big.NewInt(0xff), E: 24},
{D: big.NewInt(0xff), E: 32},
}
if !SumEquals(got, expect) {
t.Fatalf("got %v expect %v", got, expect)
}
}
func TestAlgorithm(t *testing.T) {
a := NewAlgorithm(
SlidingWindow{K: 4},
contfrac.NewAlgorithm(contfrac.DichotomicStrategy{}),
)
n := big.NewInt(587257)
c := algtest.AssertChainAlgorithmProduces(t, a, n)
t.Log(c)
}
func TestPrimitive(t *testing.T) {
// These tests are designed to verify that primitive dictionary reduction is
// doing sensible things, therefore we construct a dictionary algorithm with a
// decomposer that's going to have obvious results. We'll use the run length
// decomposer.
a := NewAlgorithm(
RunLength{T: 0},
contfrac.NewAlgorithm(contfrac.TotalStrategy{}),
)
// Cases are accompanied by an example of how this chain might be constructed
// if dictionary reduction is working. We simply confirm that the resulting
// chain is valid and at least as good as the example.
cases := []struct {
N *big.Int
Example addchain.Chain
}{
{
N: bigint.MustBinary("1111_0_1_0"),
Example: bigints.Int64s(
1, 2, 3, // prep
6, 12, 15, // << 2 and add 3
30, 60, 61, // << 2 and add 1
122, // << 1
),
},
{
N: bigint.MustBinary("11_0_11111111_0"),
Example: bigints.Int64s(
1, 2, 3, 6, 12, 15, // prepare 11 and 1111
24, 48, 96, 111, // << 5 add 1111
222, 444, 888, 1776, 1791, // << 4 add 1111
3582, // << 1
),
},
}
for _, c := range cases {
got := algtest.AssertChainAlgorithmProduces(t, a, c.N)
if err := c.Example.Produces(c.N); err != nil {
t.Fatalf("example is invalid: %s", err)
}
if len(got) > len(c.Example) {
t.Logf(" got: %v", got)
t.Logf("example: %v", c.Example)
t.Errorf("suboptimal result: length %d but possible in %d", len(got), len(c.Example))
}
}
}
func SumEquals(a, b Sum) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if a[i].E != b[i].E {
return false
}
if !bigint.Equal(a[i].D, b[i].D) {
return false
}
}
return true
}
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