# Mandelbrot Viewer — runtime-cost removal build

Production source of truth is `index.html`.

This build starts from the integrated five-improvement viewer and applies the A/B-supported runtime-cost removals. The numerical architecture remains direct f32 / perturbation + series / sparse recovery / finite continuation / CPU fallback.

## Validation

```bash
node tests/regression.mjs
node experiments/ab/variant_check.mjs index.html
node experiments/ab/supplement.mjs
node experiments/integrated_bench.mjs docs/removal-pass/integrated-bench.json
```

The optional real-browser WebGPU test is `tests/browser_smoke.mjs`; it requires Chromium with a working WebGPU backend.

## Current records

- `docs/removal-pass/IMPLEMENTATION.md` — why each runtime cost was removed or retained
- `docs/removal-pass/results.json` — structural checks, hashes, and A/B evidence
- `docs/removal-pass/integrated-bench.json` — post-removal CPU/surrogate benchmark

Historical investigation records remain under `docs/performance-cost-audit/` and `docs/integrated-improvements/`.

## Reported deep-view artifact fix (2026-09-29)

A reported deep URL exposed an unsafe 4th-order series jump and premature publication of FAST numerical failures. Production series acceleration is disabled pending a propagated error-bound redesign, and FAST provisional publication now occurs only after numerical failure repair. See `docs/reported-view-bugfix/IMPLEMENTATION.md`.