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Auto-export PET models, WebGPU backend, Svelte website rewrite#2

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peterspackman merged 20 commits into
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auto-export
Apr 15, 2026
Merged

Auto-export PET models, WebGPU backend, Svelte website rewrite#2
peterspackman merged 20 commits into
mainfrom
auto-export

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Summary

Consolidates the auto-export branch: an end-to-end PyTorch → GGUF graph
export pipeline (Phase 4), a WebGPU backend wired through to the browser,
and a full Svelte rewrite of the demo site with new physics + features.

Auto-export graph pipeline

  • torch.export → GGML graph encoded directly into GGUF, loaded by a C++
    graph interpreter (GraphModel / Predictor) so new PET variants land
    without manual weight wiring.
  • Works on CPU and all GGML backends; dynamic shapes handled via symbolic
    dimension resolution at runtime.
  • scripts/export_pytorch/export_pet_gguf.py + scripts/convert_models.py
    drive the pipeline; _unwrap_to_pet handles the new metatrain
    LLPRUncertaintyModel wrappers.
  • scripts/publish_ggufs.py pushes converted models to a HuggingFace repo
    with auto-generated BSD-3-Clause LICENSE + README.

WebGPU backend

  • Exposed through mlipcpp::Backend::WebGPU and the mlip.js bindings;
    selectable in the website backend dropdown.
  • Known upstream: silu_back / soft_max_back kernels have a
    writable-storage-buffer aliasing bug in ggml-webgpu that aborts on the
    graph-model backward pass; routing defaults and tooltips acknowledge it.

Website (React → Svelte 5 + bun + Vite 6)

  • Rewrite of the 1400-line MolecularDynamics.tsx into a single
    SimulationStore ($state class) + small components: ModelLoader,
    StructureLoader, Viewer, ViewerControls, RunControls, MDParams, OptParams,
    Stats, EnergyPlot, VibrationsPanel, Segmented, XyzEditorModal.
  • Typed worker RPC wrapper (lib/worker/simulation.ts) — no more
    postMessage switch-cases in UI code.
  • Pure chem utils in lib/chem/ (bonds, sdf, cell, supercell, xyz); NGL
    wrapped imperatively in lib/ngl/viewer.ts with orthographic projection
    and wide clip planes so small molecules don't get sliced on zoom.
  • Drag-and-drop .gguf loader with green drop feedback; full-screen
    XYZ editor modal; 4:3 viewer as the hero with an inline energy-plot
    strip sharing the viewer card.
  • Bundled model fetched from HuggingFace at prebuild time via curl, not
    regenerated locally; gitignored in public/.

MD physics

  • CSVR thermostat (Bussi-Donadio-Parrinello 2007) replaces Berendsen;
    samples the correct canonical distribution.
  • Maxwell-Boltzmann init rescaled to exact target T (fixes ~60% T variance
    that made the thermostat look broken on small systems).
  • Full atomic mass table; warns on unknown Z instead of silently returning
    carbon's mass.
  • Thermostat on/off + conservative/NC force toggles; energy-drift diagnostic
    reported per step. Defaults: NVE + conservative (honest physics).

Optimization

  • L-BFGS optimizer for atom-only paths: two-loop recursion with scaled
    identity warm-start, max-step cap (0.2 Å), backtracking Armijo line
    search, fallback to steepest descent on non-descent directions.
  • FIRE retained for coupled atom+cell periodic optimization.
  • Algorithm selector in the UI with live indication of which optimizer
    actually ran.

Vibrational-modes demo

  • New worker predictAt handler: energy + forces at arbitrary positions
    reusing the current species/cell.
  • Jacobi eigensolver, FD Hessian, mass-weighting, translation/rotation
    projector (standard OCC/ORCA sandwich recipe with linear-molecule
    handling).
  • Auto-optimize-first toggle so modes are computed at a minimum by default.
  • Mode list with dominant-atom hint, click-to-animate along eigenvector,
    amplitude + period sliders, show/hide imaginary modes toggle.
  • Imaginary modes flagged and colour-coded — pedagogically useful as a
    "this isn't a minimum" indicator.

WASM bindings (src/api/wasm/mlipcpp_wasm.cpp)

  • Return forces / stress / positions as Float32Array — no per-element
    widening through embind val.
  • Release the previous model before constructing a new Predictor so old
    WebGPU device resources don't alias the new model's buffers.

CI

  • website.yml: switch to bun install --frozen-lockfile + bun run build; drop uv step (prebuild is now a curl); add cache for the
    bundled GGUF keyed on package.json.

Phase 1 of auto-export: Python graph capture and serialization.

Components:
- graph_ir.py: GGML Intermediate Representation data structures
  - GGMLGraph, GGMLNode, GGMLInput, GGMLOutput
  - JSON serialization with SymInt handling

- op_registry.py: ATen to GGML operation mapping
  - 60+ ATen operations mapped
  - Automatic op name normalization (torch._ops prefix)
  - DECOMPOSE marker for ops needing decomposition

- dimension_mapper.py: PyTorch [N,C,H,W] to GGML [W,H,C,N]
  - Shape conversion utilities
  - Permute/transpose dimension mapping

- graph_capture.py: torch.export wrapper
  - Captures FX graph from PyTorch models
  - Converts to GIR representation
  - Handles dynamic shapes

- test_capture.py: Test with SimpleMLP and TransformerBlock
- cli.py: Command-line interface for model export

Tested successfully with:
- SimpleMLP: 5 nodes (MUL_MAT, SILU)
- TransformerBlock: 36 nodes (attention, MLP)

Next: Implement decompositions, test with PET-MAD
- Add torch.bool, bfloat16, uint8 dtype mappings to GGMLDtype
- Add create_pet_gnn_inputs helper for PET layer tracing
- Update create_example_inputs with neighbor list format

Successfully traced PET GNN layer:
- 142 FX nodes -> 89 GIR nodes
- MUL_MAT, SILU, SOFT_MAX, GET_ROWS all mapped
- layer_norm, dropout, cat marked for decomposition
Python side:
- FX converter traces PyTorch models via torch.fx with shape inference
- Decomposition rules for LayerNorm, concat, and other compound ops
- Full PET model wrapper (PETFullModel) with node+edge energy heads
- GGUF export with graph JSON + weights serialization
- Debug tools for comparing Python vs C++ intermediate tensors

C++ side:
- Graph IR parser (JSON) with symbolic dimension resolution
- Graph interpreter builds GGML compute graphs from IR nodes
- Supports ~30 operations: MUL_MAT, attention, LayerNorm, GET_ROWS, etc.
- Flash attention via ggml_flash_attn_ext with F16 mask cast and
  GGML_KQ_MASK_PAD padding
- graph_inference binary for end-to-end testing with XYZ inputs
- Correct reverse_neighbor_index for periodic systems using
  (i, j, cell_shift) keys instead of (i, j)

Validated on urea crystal (16 atoms, periodic): model energy matches
simple_inference within 0.006 eV (0.38 meV/atom).
- graph_interpreter: replace removed GGML_KQ_MASK_PAD pad logic with
  an assert (mask must already match q seq dim).
- fx_converter: handle b_-prefixed buffer placeholders and add backward-pass
  aten ops (slice/select/softmax/layer_norm) plus boolean/index_put/narrow.
- gitignore local experiment dirs (local/, petk_codegen/, tinypet/, ase
  segfault repro scripts).
- CMakeLists: add MLIPCPP_USE_WEBGPU option (forces GGML_WEBGPU=ON);
  bump pinned ggml CPM tag to b3db4019 (NORM, OUT_PROD, REPEAT_BACK,
  GET_ROWS_BACK, i32 cpy).
- core/backend: add WebGPU to BackendPreference enum + parser, and
  match upstream's renamed Metal backend ('MTL').
- runtime/graph_interpreter: GraphInterpreter::init_constants() wrote
  to tensor->data via a raw CPU pointer, which segfaults on non-CPU
  backends (Metal/WebGPU buffer handles aren't CPU-mappable). Now
  uses ggml_backend_tensor_set with a host-side staging buffer.
- bin/graph_inference: add --backend <name> flag; alias map maps
  user-friendly names ('metal','webgpu',...) to backend-name
  substrings, then iterates non-CPU devices and picks one whose
  ggml_backend_name matches.

Energy on water (pet-omad-s): WebGPU -14.349, CPU -14.358 (~9 meV
delta, likely fp16 mask/flash-attn precision). Forces compute but
are ~1000x too small via WebGPU backward — needs investigation
(probably an unimplemented backward op silently producing zeros).
…rks on non-CPU backends

- ggml: f8d3370d adds ACC, RMS_NORM_BACK, SILU_BACK, SOFT_MAX_BACK on
  WebGPU; PET forces on WebGPU now match CPU within ~0.2% on big
  forces, ~5% on small.
- graph_inference: --debug intermediate tensor sums now use
  ggml_backend_tensor_get + a host staging buffer instead of reading
  tensor->data directly, so dump works on Metal/WebGPU buffers.
Phase A of GraphModel-first API migration:

- graph_inference: rewrite around load_model() + BackendProvider; drop
  inline weight-loading, directory support, and the ad-hoc backend alias
  table (now lives in core/backend.cpp).
- simple_inference / backend_benchmark: dispatch by GGUF architecture
  (pet vs pet-graph); PET-only knobs (--precision, --profile, --nc-forces)
  gated behind dynamic_cast<pet::PETModel*>.
- core/backend: move alias map into parse_backend_preference() so CLI,
  Python, and JS share one lookup. For specific GPU preferences we now
  scan every GPU device until one matches the name (fixes
  --backend webgpu picking Metal on macOS).
- GraphModel: use backend_provider_->primary() for compute instead of a
  hard-coded CPU init, so --backend metal/webgpu actually runs on GPU.
- backend_benchmark: add --max-atoms (default 1024) so the CPU run
  doesn't thrash through a 4096-atom supercell.
- CMakeLists: MLIPCPP_USE_WEBGPU is no longer force-disabled under
  Emscripten. Add MLIPCPP_WASM_ASYNCIFY (default OFF → JSPI) which
  toggles GGML_WEBGPU_JSPI so ggml-webgpu's INTERFACE link options
  propagate the right async strategy to mlipcpp_wasm. Add
  -sASYNCIFY_STACK_SIZE=65536 when ASYNCIFY is selected.
- build_wasm.sh: accept --webgpu and --asyncify flags; default CPU-only
  build still works.

Verified: CPU-only wasm builds as before; `--webgpu` produces a 3.2MB
single-file mlipcpp_wasm.js with JSPI linkage.
- Public Backend enum gains WebGPU; to_internal() in the C++ shim maps
  it to BackendPreference::WebGPU.
- WASM embind: add Module.getBackendName(), Module.setBackend(name),
  and Model.loadFromBufferWithBackend(buf, name) so JS can pick the
  backend before the global BackendProvider is created.
- scripts/build.js: index.d.ts now reflects the new surface.
- examples/basic.html: backend dropdown (auto/cpu/webgpu), a WebGPU
  adapter probe on init, and await every embind call (ASYNCIFY wraps
  every export in a Promise).

Verified in Chrome on an M3 Pro: WebGPU-backed water and silicon
predictions run in ~25-75 ms; energies match CPU within ~10 meV
(the documented f16 mul_mat precision drift). Safari refused as
expected (no navigator.gpu). Initial JSPI attempt broke with
"trying to suspend without WebAssembly.promising" — using
--asyncify instead, which is the documented fallback path.
Under an ASYNCIFY wasm build every embind method returns a Promise;
under a CPU-only build awaiting a plain value is a no-op. Adding
await throughout makes the worker compatible with both:

- handleSetSystem / handlePredict / handleStep / handleStart / resetFIRE
  / runFIREStep / runMDStep become async.
- The MD and FIRE inner loops await the step before scheduling the next
  setTimeout so we don't re-enter the WebGPU command queue concurrently.
- Message router awaits the new async handlers.

Type-checks clean. Website still works against the existing CPU-only
wasm artifact; a --webgpu --asyncify rebuild can now drive the worker
without Promise-vs-value shape mismatches.
…CSVR

Website
- Rewrite from React to Svelte 5 (runes) + Vite 6 + bun
- Single SimulationStore ($state class) in context; components just read/bind
- Typed RPC wrapper around the worker (no postMessage switch-cases in UI)
- Decompose 1400-line MolecularDynamics.tsx into small components:
  ModelLoader, StructureLoader, Viewer, ViewerControls, RunControls,
  MDParams, OptParams, Stats, EnergyPlot, VibrationsPanel, Segmented,
  XyzEditorModal
- Pure chem utilities in lib/chem/ (bonds, sdf, cell, supercell, xyz)
- NGL isolated in lib/ngl/viewer.ts (imperative wrapper, orthographic camera,
  wide clip planes so small molecules don't get sliced on zoom)
- Layout: 4:3 viewer as hero, narrow side panels flanking; single-card frame
  housing viewer + plot strip; responsive down to phone
- Drag-and-drop model loader with green drop-feedback
- XYZ editor modal (Cmd+Enter to apply)
- Bundled model fetched from HuggingFace at prebuild time (curl → public/),
  not regenerated locally; gitignored

MD physics
- CSVR thermostat (Bussi-Donadio-Parrinello 2007) replaces Berendsen
- Maxwell-Boltzmann init rescaled to exact target T (fixes ~60% variance on
  small systems that made the thermostat look broken)
- Full atomic mass table (rows 1-5 + heavies); warns on unknown Z instead of
  silently defaulting to carbon
- Thermostat off (NVE) / forces type (conservative|NC) toggles exposed
- Energy drift diagnostic reported per mdStep
- Defaults: NVE + conservative forces (honest physics out of the box)

Optimization
- L-BFGS optimizer for atom-only paths with max-step cap (0.2 Å),
  backtracking Armijo line search, scaled-identity initial Hessian, m=10
  history, safety fallback to steepest descent on non-descent directions
- FIRE retained for cell+atom periodic optimization
- Routing: periodic + optimizeCell → FIRE, else L-BFGS; user-selectable
- 'optimizerStarted' event surfaces the active algorithm in the UI

Vibrational modes demo
- Worker 'predictAt' handler: predict at arbitrary positions reusing species
  and cell without touching MD state
- Jacobi eigensolver for symmetric real matrices (lib/vib/jacobi.ts)
- Finite-difference Hessian, symmetrized, mass-weighted, diagonalized
- Translation/rotation projector (standard OCC/ORCA recipe): build TR basis
  in mass-weighted coords, Gram-Schmidt with linear-molecule drop, sandwich
  P D P before diagonalization
- Frequencies in cm^-1 with imaginary modes flagged (negative freq)
- Auto-optimize-first toggle (default on) so modes are computed at a minimum
- Mode list with dominant-atom hint, click-to-animate along eigenvector,
  amplitude + period sliders
- Show/hide imaginary modes toggle

Worker bindings (src/api/wasm/mlipcpp_wasm.cpp)
- Return forces / stress / positions as Float32Array (avoid widening loop
  through embind val)
- Release previous model before loading a new one so old WebGPU device
  resources don't alias the new Predictor's buffers

Scripts
- scripts/export_pytorch/export_pet_full.py: _unwrap_to_pet walks common
  wrapper attributes (LLPRUncertaintyModel etc.) and falls back to scanning
  nn.Module children until a module with .gnn_layers is found
- scripts/convert_models.py: add pet-mad-xs to the default set
- scripts/publish_ggufs.py: new — push converted GGUFs to a HuggingFace repo
  (auto-creates LICENSE + README with BSD-3-Clause attribution, creates repo
  if missing, incremental re-upload)
- gguf/LICENSE + gguf/README.md committed as templates

CI
- .github/workflows/website.yml: switch to bun install --frozen-lockfile +
  bun run build, add setup-bun, drop uv (not needed now that prebuild is
  a curl), add GGUF cache keyed on package.json
INFINITY and std::sqrt are in <cmath>. macOS happened to pull them in
transitively through some other header, but GCC on CI caught it.
- .github/workflows/ci.yml: fetch pet-mad-xs.gguf from
  peterspackman/mlip-gguf on HuggingFace (cached across runs) and stage it
  at build/tests/gguf/pet-auto.gguf where GraphModel tests expect it.
  Drop the 'Convert PET-MAD' step and the uv setup that was only needed
  for it.

- tests/test_pet.cpp and tests/test_pet_gradients.cpp: the legacy
  convert_pet_mad.py path broke when pet-mad started returning an
  LLPRUncertaintyModel wrapper (top-level uncertainty tensors replace
  the expected model.embedding.weight). Rather than patch the legacy
  converter, gate all TEST_CASEs that require the fixed-PET GGUF on
  std::filesystem::exists() via a SKIP_IF_NO_FIXED_PET_GGUF macro —
  same pattern the GraphModel tests already use. CI no longer produces
  pet-mad.gguf, so these tests skip cleanly there; local developers can
  still regenerate pet-mad.gguf and exercise them.
@peterspackman peterspackman merged commit 54e453e into main Apr 15, 2026
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