[Autoloop: tsb-perf-evolve]

[github-actions]

🤖 Autoloop program issue for tsb-perf-evolve. The program definition below is mirrored from .autoloop/programs/tsb-perf-evolve/program.md. Edit the file to update the definition; comment on this issue to steer the agent.

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tsb perf evolve — Series.sortValues vs pandas Series.sort_values

Goal

Evolve the implementation of Series.sortValues (src/core/series.ts) so that, on the synthetic benchmark in code/benchmark.ts, tsb runs at least as fast as pandas on the equivalent Series.sort_values call (code/benchmark.py).

Concretely, we minimize the ratio

fitness = mean_ms_tsb / mean_ms_pandas

fitness < 1.0 means tsb is faster than pandas; lower is better. We will keep iterating as long as fitness keeps improving.

This is a performance-evolution program — there is one self-contained artifact (Series.sortValues), one scalar fitness (the ratio), and many plausible algorithmic families to try (comparison sort, typed-array indirect sort, dtype-dispatched non-comparison sort, batched/SoA, etc.). It is the canonical case for the AlphaEvolve strategy.

Validity invariants

1. The existing test suite for sortValues passes.
2. The function signature is unchanged: sortValues(ascending = true, naPosition: "first" | "last" = "last"): Series<T>.
3. No new runtime dependencies.
4. TypeScript strict mode satisfied.
5. Behaviour identical to reference for all dtypes, both ascending/descending, both naPosition values, and empty Series.

Target

Only modify: src/core/series.ts (sortValues method body) and .autoloop/programs/tsb-perf-evolve/code/**.

Evaluation

Metric: fitness = tsb_mean_ms / pandas_mean_ms. Lower is better. < 1.0 means tsb is faster than pandas.

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[github-actions]

🤖 Autoloop Status

Status	🟢 Active
Best Metric	— (pending CI on first iteration)
Target Metric	— (open-ended)
Iterations	1
Last Run	2026-04-23 03:52 UTC
Branch	autoloop/tsb-perf-evolve
Pull Request	(pending push)
State File	tsb-perf-evolve.md

Summary

First iteration submitted. The baseline Series.sortValues creates N boxed {v,i} objects and makes 2 extra .map() calls — high GC pressure at n=100k. This iteration (Island 1) replaces that with a Uint32Array indirect index sort, hoisting NaN pre-partition out of the comparator hot path and gathering output in a single loop. CI is the acceptance gate (sandbox has no bun). Next iteration will explore Island 3 (radix sort for finite floats) or Island 2 (packed BigInt64Array) depending on CI result.

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[github-actions]

🤖 Iteration 1 — ⏳ Pending CI

• Operator: Exploration (first run — seeding Island 1 diversity)
• Island: 1 — parallel-typed-arrays · comparison
• Change: Replace boxed {v,i} pair allocation with indirect Uint32Array index sort + NaN pre-partition
• Metric: pending CI (sandbox has no bun)
• Commit: 24bbe85
• Hypothesis: Eliminating N object allocations + removing NaN check from comparator hot path reduces GC pressure and improves branch prediction at n=100k

Key changes:

1. Pre-partition NaN/null/undefined into Uint32Array nanBuf in a single O(n) pass
2. Sort Uint32Array finBuf (finite indices) in-place with an indirect comparator — no boxed objects
3. Dispatch to one of two monomorphic comparators (ascending vs descending) for JIT specialization
4. Single gather loop instead of two .map() calls

Result: Awaiting CI validation.

Generated by Autoloop · ● 3.4M · ◷

[github-actions]

🤖 Autoloop Status

Status	🟢 Active
Best Metric	— (pending CI on iteration 1)
Target Metric	— (open-ended)
Iterations	1
Last Run	2026-04-23 04:41 UTC
Branch	autoloop/autoloop-autoloop-tsb-perf-evolve
Pull Request	(pending push)
State File	autoloop-autoloop-tsb-perf-evolve.md

Summary

Iteration 1 replaces the original Series.sortValues (N boxed {v,i} objects + 2 .map() calls) with Island 1: indirect Uint32Array index sort with NaN pre-partition. Previous attempt c001 on autoloop/tsb-perf-evolve had TypeScript errors from noUncheckedIndexedAccess (bracket-index on Uint32Array returns number | undefined); this iteration fixes that by using for...of which yields number directly. Next iteration will evaluate fitness and explore Island 3 (radix sort) or exploit Island 1 improvements.

Generated by Autoloop

Generated by Autoloop · ● 5.2M · ◷

[github-actions]

🤖 Iteration 1 — ⏳ Pending CI

• Operator: Exploration (first run — seeding Island 1 with TypeScript-compliant implementation)
• Island: 1 — parallel-typed-arrays · comparison
• Change: Replace boxed {v,i} pair allocation with indirect Uint32Array index sort + NaN pre-partition; fix noUncheckedIndexedAccess TypeScript errors using for...of gather
• Metric: pending CI (sandbox has no bun)
• Commit: 23e1d87

Key changes over original sortValues:

1. Pre-partition NaN/null/undefined into Uint32Array nanBuf in one O(n) pass (removes NaN check from comparator hot path)
2. Sort Uint32Array finBuf (finite indices) in-place via indirect comparator — zero boxed object allocations
3. Dispatch to one of two monomorphic comparators (ascending vs descending) for JIT specialization
4. Gather via for...of over TypedArray subviews (yields number, not number | undefined — fixes noUncheckedIndexedAccess TypeScript issue that caused c001 to fail CI)

Previous attempt note: c001 on autoloop/tsb-perf-evolve had identical logic but used nanBuf[i] bracket-index access which TypeScript rejects (TS2322/TS2538). Fixed here.

Result: Awaiting CI validation.

Generated by Autoloop

Generated by Autoloop · ● 5.2M · ◷