Reaction-diffusion · kimi-k3.1-pro

I need build single index, test browser. Should inspect cwd.

I'll implement polished GS canvas responsive. Grid perhaps 220x220 desktop max resolution 256. Gray Scott lap kernel weights center -1 adjacent .2 diag .05 typical stable dt 1 diffusion. Du=.16 Dv=.08, feed kill. Standard u += Du lapU - uvv + F(1-u), v += Dv lapV + uvv -(F+k)v. Multiple steps per frame e.g. 8 adaptive. Should visual contrast organic at 35/62 mitosis patterns. Initial central square radius 6 or disk. Drawing ImageData scaled image smoothing perhaps no smoothing? Use offscreen simulation canvas at grid resolution then scale to display canvas or directly main canvas fixed dimensions and imageSmoothing true. Main canvas square CSS min(70vh, etc). UI attractive scientific dark. Should have one file. Tests sample early fields pointer interactions pause etc. Could expose no globals needed but can status stats generation. Actual browser inspect. Should implement 256 grid? CPU 8*65k ~500k/frame easy JS 30m/s. 240 8=460k. For rich patterns, grid 256. dt=1.0 dx standard. Work per frame bound e.g. 8 steps. Device pixel ratio canvas for display with drawImage. Use offscreen fixed grid, main actual dpr. Main canvas pointer mapping. Reset seed center disk radius 8, V=.5 plus noise? requirement initial fill U=1 V=0 then central seed. Noise only central deterministic perhaps V .5 U .5. Organic pattern from square gives symmetrical. Multiple central tiny blobs? "small central region with V and reduced U" single disk. Use radius 8 V=0.5 U=0.5 perhaps pattern takes time. F=.035 k=.062 generates worms. Should early evolution likely seed expands.

Render colormap contrast, perhaps background deep navy, V vibrant teal orange. map v thresholds. Should use U perhaps shading. RGB interpolations: v 0 dark #07141d; low .05 #123c47; .18 #20a083; .35 #d1dc78; .5 #ffad60. Gray Scott v values ~0.3. Contrasting cyan and orange. Build LUT 256 based on v*900 clipped. Use chemical V. Glow visually.

Stats UI: state live, step count, V range? simple generation and brush size. Pause button, reset, speed select perhaps not necessary but can steps buttons. Responsive controls and instructions. Should have no network. Accessibility. pointer down set capture paint, pointer move only if down. Clicking adds. Paint radius ~5 grid. Brush circular continuous line interpolation to prevent gaps. Avoid browser touch scrolling canvas touch-action none. Paused still allows paint and render. Reset sets seed and steps=0; paused? reset restore initial fields and seed; probably preserve pause state? likely reset sets running true intuitive. Could preserve? Requirement reset initial scene compare central initial, easiest reset pauses? User wants reset then compare, could reset while running and quickly evolves. Usually Reset resets fields and resumes. For visual comparison initial screenshot after immediate reset with live still little change. Better reset preserve current running state? If running restarts. Test can pause then reset remains paused and exact. Implement reset keeps running state. Initial is running.

Should have "Sample early field evolution" browser can inspect status step changes and canvas screenshot. "seed separate region pointer check affects following frames". I'll test screenshot perhaps pixel inspect via evaluate not available browser only inspect DOM console perhaps inspect returns. Browser can click/drag screenshot. Could build debug window simulation? Not necessary but perhaps for verification expose canvas data attributes steps? status. Can browser inspect output console. I can add canvas dataset.generation = step and active chemical min/max? Not needed but useful. Could attach window.__rd for tests? Avoid production debug. Could use inspect.

Should write.

Now browser run inspect.

Looks nice. Should test seed pointer. Current canvas x 50-860 y124-? square 810, visible central x454 y530. Click near x650 y350.

Interesting time jumped 13k between calls; browser time perhaps seconds. Fine. Should pause verify generation stays then resume. Click pause.

Perhaps inspect after delay.

Reset while paused screenshot.

Good. Resume then perhaps test drag from reset or current.

Perhaps drag separate region.

Wait canvas in latest image from x51 to860 width 810 but height clipping at bottom 800, canvas square extends to934. Fine. Pointer drag at y360 etc produced blob at y405 visible. Good.

Should consider actual performance: browser calls take simulated minutes because screenshot? It evolves very fast? 30k steps in tool latency perhaps actual 60 sec? Fine.

Potential issues:
- Responsive aside at mobile but okay.
- render loop when paused does not update if brush after yes.
- reset seedDisk radius uses `(cx+dx+N)%N` fine cx perhaps N-1 pointer max N-1.
- click pointerCell if event at exact right could x=N but modulo handles.
- Stable dt diffusion 0.16 etc okay.
- No clamp after solve but physical stable values.
- "choose stable time and spatial steps" dt=1 dx=1.
- Work bounded 8 per frame. N=256.
- "Initially fill field ... seed small central region" yes.
- reset compare initial yes.

Perhaps run console no errors. Done. Could respond concise with what was checked and what remains unverified. Should mention drag and pointer region propagation seen, pause held count 15728, reset step0 seed. Resume count. No remaining unverified? mobile/touch and long-term numerical stability unverified perhaps long-term pattern did reach 30k no NaNs. Could say touch/mobile not explicitly tested. Respond with path.