bd4b0d3244
- selector: tournament selection for parent sampling from island populations - prompt: assembles evolution prompts from parent code, replay analysis, and meta description - llm: OpenAI-compatible client routing to ZAI proxy with fast (GLM-5-Turbo) and strong (GLM-5) tiers, plus code block extraction from model responses - Tests for prompt assembly, code extraction, and tournament selection Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
55 lines
1.6 KiB
Go
55 lines
1.6 KiB
Go
// Package selector implements parent sampling strategies for the evolution
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// pipeline. The primary strategy is tournament selection, which balances
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// selection pressure (favoring fit individuals) with diversity (random
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// sampling prevents premature convergence).
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package selector
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import (
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"math/rand"
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evolverdb "github.com/aicodebattle/acb/cmd/acb-evolver/internal/db"
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)
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// TournamentSelect picks the highest-fitness program from k randomly sampled
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// candidates drawn without replacement from programs.
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//
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// When k ≥ len(programs) the function returns the globally best program.
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// Returns nil when programs is empty.
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func TournamentSelect(programs []*evolverdb.Program, k int, rng *rand.Rand) *evolverdb.Program {
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if len(programs) == 0 {
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return nil
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}
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// If k covers the whole population, just return the global best.
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if k >= len(programs) {
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best := programs[0]
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for _, p := range programs[1:] {
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if p.Fitness > best.Fitness {
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best = p
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}
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}
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return best
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}
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// Sample k distinct indices using a Fisher-Yates partial shuffle.
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indices := rng.Perm(len(programs))[:k]
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best := programs[indices[0]]
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for _, idx := range indices[1:] {
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if programs[idx].Fitness > best.Fitness {
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best = programs[idx]
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}
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}
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return best
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}
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// SelectParents draws n parents via tournament selection with tournament size k.
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// The same program may be selected more than once (sampling with replacement
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// across tournaments).
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func SelectParents(programs []*evolverdb.Program, n, k int, rng *rand.Rand) []*evolverdb.Program {
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parents := make([]*evolverdb.Program, n)
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for i := range parents {
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parents[i] = TournamentSelect(programs, k, rng)
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}
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return parents
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}
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