feat: new optimization methods + poetry to hatch + cleaner linear search

- new optimization methods
- poetry to hatch
- cleaner linear search

.github/workflows/ci.yaml

@@ -0,0 +1,62 @@
+name: Build, test and publish
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - "*"
+  pull_request:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-python@v5
+        name: Install Python
+        with:
+          python-version: "3.10"
+      - name: Build sdist and wheel
+        run: |
+          python -m pip install -U pip
+          python -m pip install -U build
+          python -m build .
+      - uses: actions/upload-artifact@v4
+        with:
+          path: dist/*
+
+  test:
+    runs-on: ubuntu-latest
+    needs: [build]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+      - name: Install dependencies
+        run: python -m pip install -U pip
+      - name: Install package and test dependencies
+        run: python -m pip install ".[dev]"
+      - name: Run tests
+        run: python -m pytest
+
+  publish:
+    environment:
+      name: pypi
+      url: https://pypi.org/p/portrait
+    permissions:
+      id-token: write
+    needs: [test]
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: artifact
+          path: dist
+      - uses: pypa/gh-action-pypi-publish@v1.8.14

docs/index.md

@@ -61,8 +61,6 @@ Efficient detection of planets transiting quiet or active stars
 
 markdown/install
 notebooks/motivation.ipynb
-notebooks/star.ipynb
-notebooks/templates.ipynb
 examples.md
 ```
 
@@ -81,5 +79,8 @@ notebooks/tutorials/exocomet.ipynb
 :caption: Reference
 
 markdown/how.ipynb
+notebooks/star.ipynb
+notebooks/templates.ipynb
+markdown/hardware.md
 markdown/API
 ```

docs/markdown/hardware.md

@@ -0,0 +1,102 @@
+# Hardware acceleration
+
+When running the linear search, nuance exploits the parallelization capabilities of JAX by using a default mapping strategy depending on the available devices.
+
+## Solving for `(t0, D)`
+
+To solve a particular model (like a transit) with a given epoch `t0` and duration `D`, we define the function
+
+```python
+import jax
+
+@jax.jit
+def solve(t0, D):
+    m = model(time, t0, D)
+    ll, w, v = nu._solve(m)
+    return w[-1], v[-1, -1], ll
+```
+
+where `model` is the [template model](../notebooks/templates.ipynb), and `nu._solve` is the `Nuance._solve` method returning:
+
+- `w[-1]` the template model depth
+- `v[-1, -1]` the variance of the template model depth
+- `ll` the log-likelihood of the data to the model
+
+## Batching over `(t0s, Ds)`
+The goal of the linear search is then to call `solve` for a grid of of epochs `t0s` and durations `Ds`. As `t0s` is usually very large compared to `Ds` (~1000 vs. ~10), the default strategy is to batch the `t0s`:
+
+```python
+# we pad to have fixed size batches
+t0s_padded = np.pad(t0s, [0, batch_size - (len(t0s) % batch_size) % batch_size])
+t0s_batches = np.reshape(
+    t0s_padded, (len(t0s_padded) // batch_size, batch_size)
+)
+```
+
+## JAX mapping
+
+In order to solve a given batch in an optimal way, the `batch_size` can be set depending on the devices available:
+
+- If multiple **CPUs** are available, the `batch_size` is chosen as the number of devices (`jax.device_count()`) and we can solve a given batch using
+
+    ```python
+    solve_batch = jax.pmap(jax.vmap(solve, in_axes=(None, 0)), in_axes=(0, None))
+    ```
+
+    where each batch is `jax.pmap`ed over all available CPUs along the `t0s` axis. 
+
+- If a **GPU** is available, the `batch_size` can be larger and the batch is `jax.vmap`ed along `t0s`
+
+    ```python
+    solve_batch = jax.vmap(jax.vmap(solve, in_axes=(None, 0)), in_axes=(0, None))
+    ```
+
+Then, the linear search consists in iterating over `t0s_batches`:
+
+```python
+results = []
+
+for t0_batch in t0s_batches:
+    results.append(solve_batch(t0_batch, Ds))
+```
+
+```{note}
+Of course, one familiar with JAX can use their own mapping strategy to evaluate `solve` over a grid of epochs `t0s` and durations `Ds`.
+```
+
+## The full method
+
+The method `nuance.Naunce.linear_search` is then
+
+```python
+def linear_search( self, t0s, Ds):
+
+    backend = jax.default_backend()
+    batch_size = {"cpu": DEVICES_COUNT, "gpu": 1000}[backend]
+
+    @jax.jit
+    def solve(t0, D):
+        m = self.model(self.time, t0, D)
+        ll, w, v = self._solve(m)
+        return jnp.array([w[-1], v[-1, -1], ll])
+
+    # Batches
+    t0s_padded = np.pad(t0s, [0, batch_size - (len(t0s) % batch_size) % batch_size])
+    t0s_batches = np.reshape(
+        t0s_padded, (len(t0s_padded) // batch_size, batch_size)
+    )
+
+    # Mapping
+    if backend == "cpu":
+        solve_batch = jax.pmap(jax.vmap(solve, in_axes=(None, 0)), in_axes=(0, None))
+    else:
+        solve_batch = jax.vmap(jax.vmap(solve, in_axes=(None, 0)), in_axes=(0, None))
+
+    # Iterate
+    results = []
+
+    for t0_batch in t0s_batches:
+        results.append(solve_batch(t0_batch, Ds))
+
+    ...
+```

nuance/core.py

@@ -2,9 +2,10 @@
 
 import jax
 import jax.numpy as jnp
+import jaxopt
 
 
-def eval_model(flux, X, gp):
+def solve(flux, X, gp):
     Liy = gp.solver.solve_triangular(flux)
     LiX = gp.solver.solve_triangular(X.T)
 
@@ -22,6 +23,36 @@ def function(m):
     return function
 
 
+def gp_model(x, y, build_gp, X=None):
+
+    if X is None:
+        X = jnp.atleast_2d(jnp.ones_like(x))
+
+    @jax.jit
+    def nll_w(params):
+        gp = build_gp(params, x)
+        Liy = gp.solver.solve_triangular(y)
+        LiX = gp.solver.solve_triangular(X.T)
+        LiXT = LiX.T
+        LiX2 = LiXT @ LiX
+        w = jnp.linalg.lstsq(LiX2, LiXT @ Liy)[0]
+        nll = -gp.log_probability(y - w @ X)
+        return nll, w
+
+    @jax.jit
+    def nll(params):
+        return nll_w(params)[0]
+
+    @jax.jit
+    def mu(params):
+        gp = build_gp(params, x)
+        _, w = nll_w(params)
+        cond_gp = gp.condition(y - w @ X, x).gp
+        return cond_gp.loc + w @ X
+
+    return mu, nll
+
+
 def transit_protopapas(t, t0, D, P=1e15, c=12):
     _t = P * jnp.sin(jnp.pi * (t - t0) / P) / (jnp.pi * D)
     return -0.5 * jnp.tanh(c * (_t + 1 / 2)) + 0.5 * jnp.tanh(c * (_t - 1 / 2))