feat(loop-interpolation-core): add a low-memory native solver for Python and the browser

.github/workflows/core-wheels.yml

@@ -0,0 +1,91 @@
+name: "Native wheels"
+
+# Build the wheels and the sdist of loop-interpolation-core.
+# pypi.yml calls this workflow and then publishes the files.
+# A pull request that changes the crate also runs it, so a broken wheel
+# build shows before a release.
+#
+# The crate uses abi3-py39, so one wheel for each platform works with all
+# Python versions from 3.9.
+
+on:
+  workflow_call:
+  pull_request:
+    branches:
+      - master
+    paths:
+      - 'packages/loop_interpolation_core/**'
+      - '.github/workflows/core-wheels.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  MANIFEST: packages/loop_interpolation_core/Cargo.toml
+
+jobs:
+  wheels:
+    name: Wheel ${{ matrix.platform.name }}
+    runs-on: ${{ matrix.platform.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        platform:
+          - { name: linux-x86_64, runner: ubuntu-latest, target: x86_64, smoke: true }
+          - { name: linux-aarch64, runner: ubuntu-24.04-arm, target: aarch64, smoke: true }
+          - { name: macos-arm64, runner: macos-latest, target: aarch64, smoke: true }
+          # Cross-compiled on the arm64 runner, so it is not run here.
+          - { name: macos-x86_64, runner: macos-latest, target: x86_64, smoke: false }
+          - { name: windows-x86_64, runner: windows-latest, target: x64, smoke: true }
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      # On Linux the build runs in a manylinux container.
+      - name: Build the wheel
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.platform.target }}
+          manylinux: auto
+          args: --release --out dist --manifest-path ${{ env.MANIFEST }}
+      - name: Install the wheel and solve a small problem
+        if: matrix.platform.smoke
+        shell: bash
+        run: |
+          python -m pip install numpy
+          python -m pip install --no-index --find-links dist loop-interpolation-core
+          python - <<'EOF'
+          import numpy as np
+          import loop_interpolation_core as core
+
+          problem = core.Problem([0.0, 0.0, 0.0], [8, 8, 8], [1.0, 1.0, 1.0])
+          points = np.array([2.0, 2.0, 2.0, 5.0, 5.0, 5.0])
+          problem.add_value(points, np.array([0.0, 1.0]), np.ones(2))
+          field, report = problem.solve({})
+          assert report["converged"], report
+          assert field.shape == (512,), field.shape
+          print("solve converged in", report["iterations"], "iterations")
+          EOF
+      - uses: actions/upload-artifact@v4
+        with:
+          name: core-wheel-${{ matrix.platform.name }}
+          path: dist/*.whl
+          if-no-files-found: error
+
+  sdist:
+    name: Sdist
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build the sdist
+        uses: PyO3/maturin-action@v1
+        with:
+          command: sdist
+          args: --out dist --manifest-path ${{ env.MANIFEST }}
+      - uses: actions/upload-artifact@v4
+        with:
+          name: core-sdist
+          path: dist/*.tar.gz
+          if-no-files-found: error

.github/workflows/linter.yml

@@ -46,12 +46,16 @@ jobs:
       - name: Lint with ruff
         run: |
           ruff check ${{ env.PROJECT_FOLDERS }} --fix --exit-zero
+      # A pull request from a fork gets a read-only GITHUB_TOKEN, so it
+      # cannot push the style branch. Skip the push and the PR for it.
       - uses: stefanzweifel/git-auto-commit-action@v5
+        if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
         with:
           commit_message: "style: style fixes by ruff and autoformatting by black"
           branch: lint/style-fixes-${{ github.run_id }}
           create_branch: true
       - name: Create Pull Request
+        if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
         uses: peter-evans/create-pull-request@v6
         with:
           token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/native.yml

@@ -0,0 +1,218 @@
+name: "Native solver"
+
+# This workflow checks the Rust crate loop_interpolation_core.
+# It runs only when the crate, the Python adapter or this file changes.
+
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - 'packages/loop_interpolation_core/**'
+      - 'packages/loop_interpolation/src/loop_interpolation/_native.py'
+      - '.github/workflows/native.yml'
+  pull_request:
+    branches:
+      - master
+    paths:
+      - 'packages/loop_interpolation_core/**'
+      - 'packages/loop_interpolation/src/loop_interpolation/_native.py'
+      - '.github/workflows/native.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+  MANIFEST: packages/loop_interpolation_core/Cargo.toml
+
+jobs:
+  # Format, lint and test the crate with all feature sets.
+  rust:
+    name: Rust checks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install the Rust toolchain
+        run: |
+          rustup toolchain install stable --profile minimal --component rustfmt --component clippy --target wasm32-unknown-unknown
+          rustup default stable
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            packages/loop_interpolation_core/target
+          key: rust-${{ runner.os }}-${{ hashFiles('packages/loop_interpolation_core/Cargo.lock') }}
+          restore-keys: rust-${{ runner.os }}-
+      - name: Format
+        run: cargo fmt --manifest-path "$MANIFEST" --check
+      - name: Clippy, no features
+        run: cargo clippy --manifest-path "$MANIFEST" --all-targets -- -D warnings
+      - name: Clippy, parallel
+        run: cargo clippy --manifest-path "$MANIFEST" --all-targets --features parallel -- -D warnings
+      - name: Clippy, python
+        run: cargo clippy --manifest-path "$MANIFEST" --all-targets --features python -- -D warnings
+      - name: Clippy, wasm
+        run: cargo clippy --manifest-path "$MANIFEST" --all-targets --features wasm --target wasm32-unknown-unknown -- -D warnings
+      # Use --release. Debug test runs take many minutes.
+      - name: Test, no features
+        run: cargo test --manifest-path "$MANIFEST" --release
+      - name: Test, parallel
+        run: cargo test --manifest-path "$MANIFEST" --release --features parallel
+
+  # Build the Python wheel and run the Python tests with the native core installed.
+  wheel:
+    name: Wheel ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            packages/loop_interpolation_core/target
+          key: wheel-${{ runner.os }}-${{ hashFiles('packages/loop_interpolation_core/Cargo.lock') }}
+          restore-keys: wheel-${{ runner.os }}-
+      # maturin develop needs a virtual environment.
+      # The Linux and macOS folder is bin. The Windows folder is Scripts.
+      - name: Install, build and test
+        shell: bash
+        run: |
+          python -m venv .venv
+          if [ -f .venv/Scripts/activate ]; then source .venv/Scripts/activate; else source .venv/bin/activate; fi
+          python -m pip install --upgrade pip
+          python -m pip install maturin numpy scipy pytest
+          python -m pip install -e packages/loop_common -e packages/loop_interpolation
+          maturin develop --release -m packages/loop_interpolation_core/Cargo.toml
+          python -m pytest packages/loop_interpolation/tests -q
+
+  # Build the WebAssembly package, check its size and run the browser tests.
+  wasm:
+    name: WebAssembly
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Install the Rust toolchain
+        run: |
+          rustup toolchain install stable --profile minimal --target wasm32-unknown-unknown
+          rustup default stable
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            packages/loop_interpolation_core/target
+          key: wasm-${{ runner.os }}-${{ hashFiles('packages/loop_interpolation_core/Cargo.lock') }}
+          restore-keys: wasm-${{ runner.os }}-
+      # The wasm-bindgen CLI version must equal the wasm-bindgen version in Cargo.lock.
+      - name: Read the wasm-bindgen version
+        run: |
+          V=$(grep -A1 '^name = "wasm-bindgen"$' packages/loop_interpolation_core/Cargo.lock | sed -n 's/^version = "\(.*\)"$/\1/p')
+          echo "Version: $V"
+          test -n "$V"
+          echo "WASM_BINDGEN_VERSION=$V" >> "$GITHUB_ENV"
+      - name: Cache the wasm-bindgen CLI
+        id: bindgen-cache
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/bin/wasm-bindgen
+          key: wasm-bindgen-cli-${{ runner.os }}-${{ env.WASM_BINDGEN_VERSION }}
+      - name: Install the wasm-bindgen CLI
+        if: steps.bindgen-cache.outputs.cache-hit != 'true'
+        run: cargo install wasm-bindgen-cli --version "$WASM_BINDGEN_VERSION" --locked
+      - name: Build the WebAssembly package
+        run: bash packages/loop_interpolation_core/scripts/build_wasm.sh
+      - name: Check the size
+        run: python -I packages/loop_interpolation_core/scripts/check_wasm_size.py
+      - name: Install the browser test packages
+        working-directory: packages/loop_interpolation_core/tests_web
+        run: |
+          npm ci
+          npx playwright install --with-deps chromium
+      - name: Browser tests
+        working-directory: packages/loop_interpolation_core/tests_web
+        run: npm test
+
+  # Slow reference runs. Start these by hand only.
+  reference:
+    name: Reference problems
+    if: github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Install the Rust toolchain
+        run: |
+          rustup toolchain install stable --profile minimal --target wasm32-unknown-unknown
+          rustup default stable
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            packages/loop_interpolation_core/target
+          key: reference-${{ runner.os }}-${{ hashFiles('packages/loop_interpolation_core/Cargo.lock') }}
+          restore-keys: reference-${{ runner.os }}-
+      - name: Read the wasm-bindgen version
+        run: |
+          V=$(grep -A1 '^name = "wasm-bindgen"$' packages/loop_interpolation_core/Cargo.lock | sed -n 's/^version = "\(.*\)"$/\1/p')
+          test -n "$V"
+          echo "WASM_BINDGEN_VERSION=$V" >> "$GITHUB_ENV"
+      - name: Cache the wasm-bindgen CLI
+        id: bindgen-cache
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/bin/wasm-bindgen
+          key: wasm-bindgen-cli-${{ runner.os }}-${{ env.WASM_BINDGEN_VERSION }}
+      - name: Install the wasm-bindgen CLI
+        if: steps.bindgen-cache.outputs.cache-hit != 'true'
+        run: cargo install wasm-bindgen-cli --version "$WASM_BINDGEN_VERSION" --locked
+      # The test f32_250_cubed_within_budget is too slow for CI. Skip it.
+      - name: Ignored Rust tests
+        run: |
+          set -o pipefail
+          cargo test --manifest-path "$MANIFEST" --release --test reference_problems -- --ignored --nocapture --test-threads=1 --skip f32_250_cubed_within_budget 2>&1 | tee rust_reference.log
+      - name: Write the reference field
+        run: cargo test --manifest-path "$MANIFEST" --release --test reference_problems r1_write_field -- --ignored
+      - name: Build the WebAssembly package
+        run: bash packages/loop_interpolation_core/scripts/build_wasm.sh
+      - name: Browser reference spec
+        working-directory: packages/loop_interpolation_core/tests_web
+        env:
+          RUN_REFERENCE: '1'
+        run: |
+          set -o pipefail
+          npm ci
+          npx playwright install --with-deps chromium
+          npm test -- reference 2>&1 | tee "$GITHUB_WORKSPACE/browser_reference.log"
+      - name: Write the job summary
+        if: always()
+        run: |
+          {
+            echo "## Rust reference problems"
+            echo '```'
+            cat rust_reference.log 2>/dev/null || echo "No output."
+            echo '```'
+            echo "## Browser reference spec"
+            echo '```'
+            cat browser_reference.log 2>/dev/null || echo "No output."
+            echo '```'
+          } >> "$GITHUB_STEP_SUMMARY"

.github/workflows/pypi.yml

@@ -6,6 +6,33 @@ permissions:
   contents: read
 
 jobs:
+  # loop-interpolation-core is the Rust core behind the optional extra
+  # loop-interpolation[native]. It has compiled wheels, so it is built by
+  # core-wheels.yml and not by the sdist matrix below. No other package
+  # waits for it: a failed core upload does not stop their release.
+  build_core:
+    name: Build loop-interpolation-core
+    uses: ./.github/workflows/core-wheels.yml
+
+  # Trusted publishing (OIDC): no password. PyPI must list this repository
+  # and the workflow file pypi.yml as a trusted publisher of the project.
+  upload_core_to_pypi:
+    name: Upload loop-interpolation-core to PyPI
+    needs: ["build_core"]
+    runs-on: ubuntu-latest
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: core-*
+          path: dist
+          merge-multiple: true
+      - uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          skip-existing: true
+          verbose: true
+
   # loop_common/loop_interpolation/loopstructural_visualisation are
   # workspace-local deps of LoopStructural (see [tool.uv.sources] in
   # pyproject.toml) — loop_common/loop_interpolation are runtime deps,

.gitignore

@@ -143,3 +143,9 @@ sandbox/*
 
 # codebase-graph
 .codebaseGraph/
+
+# loop_interpolation_core build output (wasm pkg) and browser test dependencies
+packages/loop_interpolation_core/pkg/
+packages/loop_interpolation_core/tests_web/node_modules/
+packages/loop_interpolation_core/tests_web/test-results/
+packages/loop_interpolation_core/tests_web/playwright-report/

.release-please-config.json

@@ -8,6 +8,7 @@
       "exclude-paths": [
         "packages/loop_common",
         "packages/loop_interpolation",
+        "packages/loop_interpolation_core",
         "packages/map2loop",
         "packages/loopstructural_visualisation"
       ]
@@ -20,6 +21,17 @@
       "release-type": "python",
       "component": "loop-interpolation"
     },
+    "packages/loop_interpolation_core": {
+      "release-type": "python",
+      "component": "loop-interpolation-core",
+      "extra-files": [
+        {
+          "type": "toml",
+          "path": "Cargo.toml",
+          "jsonpath": "$.package.version"
+        }
+      ]
+    },
     "packages/map2loop": {
       "release-type": "python",
       "component": "map2loop"