Faster state tracking, stable optimizer

genseed/genseed.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"log"
 	"os"
+	"slices"
 
 	"github.com/samber/lo"
 	"github.com/securemesh/coding"
@@ -42,6 +43,7 @@ func optimize(st *state.State, samples [][]byte) *state.State {
 }
 
 type sampleResult struct {
+	symbol byte
 	state *state.State
 	score int
 }
@@ -50,29 +52,33 @@ func optimize2(baseState *state.State, samples [][]byte) *state.State {
 	ch := make(chan sampleResult, 100)
 
 	for i := 0; i < 256; i++ {
-		s := byte(i)
+		res := sampleResult{
+			symbol: byte(i),
+		}
+
 		go func () {
 			st := baseState.Clone()
-			st.IncrementSymbol(s)
-			ch <- sampleResult{
-				state: st,
-				score: totalLength(st, samples),
-			}
+			st.IncrementSymbol(res.symbol)
+			res.state = st
+			res.score = totalLength(st, samples)
+			ch <- res
 		}()
 	}
 
-	var best *state.State = nil
-	bestScore := totalLength(baseState, samples)
+	results := []sampleResult{}
 
 	for i := 0; i < 256; i++ {
-		res := <-ch
-		if res.score < bestScore {
-			best = res.state
-			bestScore = res.score
-		}
+		results = append(results, <-ch)
 	}
 
-	return best
+	slices.SortFunc(results, func(a, b sampleResult) int { return int(a.symbol) - int(b.symbol) })
+	best := slices.MaxFunc(results, func(a, b sampleResult) int { return b.score - a.score })
+
+	if best.score == totalLength(baseState, samples) {
+		return nil
+	}
+
+	return best.state
 }
 
 func totalLength(st *state.State, samples [][]byte) int {

seeds/seeds.go

@@ -15,12 +15,10 @@ var chatState = newStateFromSeed([][]byte{
 	/* 08 */ []byte("i"),
 	/* 09 */ []byte(""),
 	/* 10 */ []byte(" "),
-	/* 11 */ []byte(""),
+	/* 11 */ []byte("e"),
 	/* 12 */ []byte(""),
-	/* 13 */ []byte(""),
-	/* 14 */ []byte("et"),
-	/* 15 */ []byte(""),
-	/* 16 */ []byte("o"),
+	/* 13 */ []byte("t"),
+	/* 14 */ []byte("o"),
 })
 
 func ChatState() *state.State {

state/state.go

@@ -12,7 +12,7 @@ type node struct {
 }
 
 type State struct {
-	nodes    []*node
+	nodes    [256]node
 	bySymbol map[byte]int
 }
 
@@ -22,10 +22,7 @@ func NewState() *State {
 	}
 
 	for i := 0; i < 256; i++ {
-		st.nodes = append(st.nodes, &node{
-			symbol: byte(i),
-		})
-
+		st.nodes[i].symbol = byte(i)
 		st.bySymbol[byte(i)] = i
 	}
 
@@ -33,16 +30,10 @@ func NewState() *State {
 }
 
 func (st State) Clone() *State {
-	st2 := &State{
+	return &State{
+		nodes: st.nodes,
 		bySymbol: maps.Clone(st.bySymbol),
 	}
-
-	for _, node := range st.nodes {
-		tmp := *node
-		st2.nodes = append(st2.nodes, &tmp)
-	}
-
-	return st2
 }
 
 // Returns old index
@@ -61,11 +52,8 @@ func (st *State) IncrementSymbol(symbol byte) int {
 			break
 		}
 
-		st.nodes[iterIndex] = prevNode
-		st.bySymbol[prevNode.symbol] = iterIndex
-
-		st.nodes[prevIndex] = iterNode
-		st.bySymbol[iterNode.symbol] = prevIndex
+		st.nodes[iterIndex], st.nodes[prevIndex] = prevNode, iterNode
+		st.bySymbol[iterNode.symbol], st.bySymbol[prevNode.symbol] = prevIndex, iterIndex
 	}
 
 	return nodeIndex