psann 0.10.10

PSANN: Parameterized Sine-Activated Neural Networks (primary-output, sklearn-style, PyTorch backend)

PSANN - Parameterized Sine-Activated Neural Networks

PSANN packages sine-activated Torch models behind a sklearn-style estimator surface. The stack combines:

• learnable sine activations with SIREN-friendly initialisation,
• optional learned sparse (LSM) expanders and scalers,
• persistent state controllers for streaming inference, and
• Horizon-Informed Sampling Strategy Optimisation (HISSO) for episodic training.

The current line targets primary outputs only so there are no predictive extras, secondary heads, or legacy growth schedules to maintain.

Quick links:

• API reference: docs/API.md
• Scenario walkthroughs: docs/examples/README.md
• Migration notes: docs/migration.md
• Results compendium: docs/PSANN_Results_Compendium.md
• Contributor guide: docs/CONTRIBUTING.md
• Technical design notes: TECHNICAL_DETAILS.md

Installation

python -m venv .venv
.\.venv\Scripts\Activate.ps1   # Windows PowerShell
# source .venv/bin/activate     # macOS/Linux
pip install --upgrade pip
pip install -e .                # editable install from source

Optional extras in pyproject.toml:

• psann[sklearn]: adds scikit-learn conveniences for estimator mixins and metrics.
• psann[viz]: plotting helpers used in benchmarks and notebooks.
• psann[dev]: pytest, ruff, black, coverage, build, pre-commit tooling.

Need pre-pinned builds (e.g. on Windows or air-gapped envs)? Use the compatibility extra:

pip install -e .[compat]

The compat extra pins NumPy, SciPy, scikit-learn, and PyTorch to the newest widely available wheels while keeping pyproject.toml as the single source of truth.

Running Tests

Install the development extras in editable mode so the test suite imports the packaged code without manual sys.path tweaks:

pip install -e .[dev]
python -m pytest

HISSO integration suites are marked as slow; skip them during quick iterations with:

python -m pytest -m "not slow"

The suite exercises the supported supervised, streaming, and HISSO flows. GPU-specific checks are skipped automatically when CUDA is unavailable.

Common linting commands:

python -m ruff check src tests scripts examples
python -m black --check src tests scripts examples

Set up local hooks (formatting, linting, notebook output stripping) with pre-commit:

pre-commit install
pre-commit run --all-files  # optional one-time sweep

Quick Start

Supervised regression

import numpy as np
from psann import PSANNRegressor

rs = np.random.RandomState(42)
X = np.linspace(-4, 4, 1000, dtype=np.float32).reshape(-1, 1)
y = 0.8 * np.exp(-0.25 * np.abs(X)) * np.sin(3.5 * X)

model = PSANNRegressor(
    hidden_layers=2,
    hidden_units=64,
    epochs=200,
    lr=1e-3,
    early_stopping=True,
    patience=20,
    random_state=42,
)
model.fit(X, y, verbose=1)
print("R^2:", model.score(X, y))

Behind the scenes the estimator normalises arguments via normalise_fit_args and prepares data/scalers through psann.estimators._fit_utils.prepare_inputs_and_scaler, so dense, residual, and convolutional variants share the same fit surface.

Parameter aliases. The constructor still accepts legacy names such as hidden_width and hidden_channels, but they are treated as deprecated aliases. Whether you pass them to __init__ or later through set_params, the estimator maps them back to the canonical hidden_units / conv_channels entries and warns when both names disagree.

Device & dtype. The estimators operate internally in float32. Supplying np.float32 arrays (as shown above) avoids extra copies. For GPU training, pass device="cuda" (or a specific torch.device) when constructing the estimator before calling fit; the helper will keep HISSO loops and inference on the pinned device.

Residual regression with ResPSANNRegressor

import numpy as np
from psann import ResPSANNRegressor

rng = np.random.default_rng(1234)
X = rng.uniform(-2.0, 2.0, size=(512, 4)).astype(np.float32)
y = (np.sin(X[:, :1]) + 0.25 * X[:, 1:2]).astype(np.float32)

est = ResPSANNRegressor(
    hidden_layers=4,
    hidden_units=48,
    lr=1e-3,
    epochs=120,
    early_stopping=True,
    patience=15,
    random_state=1234,
)
est.fit(X, y, verbose=0)
print("Residual R^2:", est.score(X, y))

ResPSANNRegressor keeps the same .fit/.predict interface but routes training through the residual backbone with DropPath, RMSNorm, and optional HISSO hooks enabled.

Convolutional regression with ResConvPSANNRegressor

import numpy as np
from psann import ResConvPSANNRegressor

rng = np.random.default_rng(321)
X = rng.normal(size=(64, 12, 3)).astype(np.float32)  # (N, length, channels)
y = X.mean(axis=(1, 2), keepdims=True).astype(np.float32)

conv_est = ResConvPSANNRegressor(
    hidden_layers=3,
    hidden_units=32,
    conv_channels=24,
    conv_kernel_size=3,
    epochs=60,
    batch_size=16,
    data_format="channels_last",
    random_state=321,
)
conv_est.fit(X, y, verbose=0)
print("Conv R^2:", conv_est.score(X, y))

Passing data_format="channels_last" lets you keep inputs as (N, length, channels) arrays; the estimator handles the channel-first conversion internally while respecting float32 inputs and the shared alias policy.

Wave-based regression with WaveResNetRegressor

import numpy as np
from psann import WaveResNetRegressor

X = np.linspace(0, 2 * np.pi, 400, dtype=np.float32).reshape(-1, 1)
context = np.stack(
    [np.sin(X[:, 0]), np.cos(X[:, 0])],
    axis=1,
).astype(np.float32)
y = (np.sin(3 * X) + 0.1 * np.cos(5 * X)).astype(np.float32)

wave = WaveResNetRegressor(
    hidden_layers=4,
    hidden_units=64,
    epochs=150,
    lr=3e-4,
    w0=30.0,
    w0_warmup_epochs=20,
    progressive_depth_initial=2,
    progressive_depth_interval=25,
    random_state=7,
)
wave.fit(X, y, context=context, verbose=0)
print("WaveResNet R^2:", wave.score(X, y, context=context))

WaveResNetRegressor applies SIREN-style initialisation with optional w0 warmup and progressive depth expansion. Providing explicit float32 context arrays keeps inference aligned with the estimator's cached context_dim.

Episodic HISSO with HISSOOptions

import numpy as np
from psann import PSANNRegressor, get_reward_strategy, HISSOOptions

rng = np.random.default_rng(7)
X = rng.normal(size=(512, 4)).astype(np.float32)
targets = np.sin(X.sum(axis=1, keepdims=True)).astype(np.float32)

model = PSANNRegressor(hidden_layers=2, hidden_units=48, epochs=40, batch_size=64)
model.fit(X, targets, verbose=1)  # supervised warm start

finance = get_reward_strategy("finance")
options = HISSOOptions.from_kwargs(
    window=64,
    reward_fn=finance.reward_fn,
    context_extractor=finance.context_extractor,
    primary_transform="softmax",
    transition_penalty=0.05,
    input_noise=0.0,
    supervised={"y": targets},
)

model.fit(
    X,
    y=None,
    hisso=True,
    hisso_window=options.episode_length,
    hisso_reward_fn=options.reward_fn,
    hisso_context_extractor=options.context_extractor,
    hisso_primary_transform=options.primary_transform,
    hisso_transition_penalty=options.transition_penalty,
    hisso_supervised=options.supervised,
    verbose=1,
)

HISSOOptions keeps reward, context, noise, and transformation choices in one place. The estimator records the resolved options after fitting so helpers such as psann.hisso_infer_series and psann.hisso_evaluate_reward can reuse them.

Context builders

Setting context_builder="cosine" (or supplying a callable) instructs the estimator to synthesise auxiliary context features during fit, predict, and sequence roll-outs. Builder parameter dictionaries are deep-copied, so mutating your original config after set_params will not affect the estimator. Calling set_params(context_builder=None) clears the cached builder and resets the inferred context_dim, letting you switch back to explicit context arrays cleanly.

Custom data preparation

from psann import PSANNRegressor
from psann.estimators._fit_utils import normalise_fit_args, prepare_inputs_and_scaler

est = PSANNRegressor(hidden_layers=1, hidden_units=16, scaler="standard")
fit_args = normalise_fit_args(est, X_train, y_train, hisso=False, verbose=0, lr_max=None, lr_min=None)
prepared, primary_dim, _ = prepare_inputs_and_scaler(est, fit_args)
# prepared.train_inputs / prepared.train_targets feed straight into custom loops

This keeps bespoke research loops aligned with the estimator's preprocessing contract without relying on deprecated extras heads.

Core components

• Sine activations (psann.SineParam) expose learnable amplitude, frequency, and decay with optional bounds and SIREN-friendly initialisation.
• LSM expanders (psann.LSM, psann.LSMExpander, psann.LSMConv2d, psann.LSMConv2dExpander) provide sparse learned feature maps; build_preprocessor wires dict specs or modules into estimators with optional pretraining and separate learning rates.
• State controllers (psann.StateController) keep per-feature persistent gains for streaming/online workflows. Configurable via StateConfig.
• Shared fit helpers (psann.estimators._fit_utils) normalise arguments, materialise scalers, route through residual and convolutional builders, and orchestrate HISSO plans.
• Wave backbones (psann.WaveResNet, psann.WaveEncoder, psann.WaveRNNCell, psann.scan_regimes) surface the standalone components for experiments and spectral diagnostics outside the sklearn wrappers.
• HISSO (psann.HISSOOptions, psann.hisso_infer_series, psann.hisso_evaluate_reward) offers declarative reward configuration, supervised warm starts, episode construction, and inference helpers that reuse the cached configuration.
• Utilities (psann.jacobian_spectrum, psann.ntk_eigens, psann.participation_ratio, psann.mutual_info_proxy, psann.encode_and_probe, psann.fit_linear_probe, psann.make_context_rotating_moons, psann.make_drift_series, psann.make_shock_series, psann.make_regime_switch_ts) cover diagnostics and synthetic regimes.
• Token helpers (SimpleWordTokenizer, SineTokenEmbedder) remain for experiments that need sine embeddings, but no language-model trainer ships in this release.

HISSO at a glance

1. Call HISSOOptions.from_kwargs(...) (or supply equivalent kwargs to fit) to resolve episode length, reward function, primary transform, transition penalty, context extractor, and optional noise.
2. Provide hisso_supervised to run a warm-start supervised phase before episodic optimisation.
3. PSANNRegressor.fit(..., hisso=True, ...) builds the episodic trainer using the shared fit pipeline.
4. After training, hisso_infer_series(estimator, series) and hisso_evaluate_reward(estimator, series, targets=None) reuse the cached configuration to score new data.

The project ships CPU benchmark baselines (docs/benchmarks/) and CI scripts (scripts/benchmark_hisso_variants.py, scripts/compare_hisso_benchmarks.py) to catch HISSO regressions.

HISSO logging CLI

Use python -m psann.scripts.hisso_log_run to run HISSO sessions on remote nodes and collect reproducible artefacts. The command accepts JSON/YAML configs (see configs/hisso/ templates) and emits:

• metrics.json with loss/reward/throughput summaries and optional portfolio metrics.
• events.csv containing append-only epoch logs and runtime notes (device, shuffle policy, AMP state).
• checkpoints/ with the best estimator snapshot (and latest.pt when --keep-checkpoints is passed).
• config_resolved.yaml mirroring the resolved estimator/device settings for traceability.

Example:

python -m psann.scripts.hisso_log_run \
  --config configs/hisso/dense_cpu_smoke.yaml \
  --output-dir runs/hisso \
  --run-name dense_cpu_debug \
  --device cpu \
  --seed 7

When device points to a CUDA target and the config enables mixed_precision, the trainer switches to AMP + GradScaler automatically.

Looking for a guided walkthrough? Use the paired notebooks (both ship with Colab badges):

• notebooks/HISSO_Logging_CLI_Walkthrough.ipynb – CPU-first dry run with TODO placeholders.
• notebooks/HISSO_Logging_GPU_Run.ipynb – installs the released PyPI wheel and executes the logging CLI on CUDA to collect final metrics and checkpoints.

Convolutional stems

PSANNRegressor.with_conv_stem(...) and ResPSANNRegressor.with_conv_stem(...) return estimators wired into the convolutional training path without instantiating the legacy *ConvPSANNRegressor wrappers. The helpers enable preserve_shape, switch training to channel-first tensors, and honour conv_channels, conv_kernel_size, and per_element flags. Example:

est = PSANNRegressor.with_conv_stem(
    hidden_layers=2,
    hidden_units=32,
    conv_channels=16,
    conv_kernel_size=3,
    epochs=20,
    batch_size=32,
    random_state=42,
)
est.fit(images, targets)

Residual variants reuse the same call while producing ResidualPSANNConv2dNet cores when 2D inputs are supplied.

Stateful dataloaders

When stateful=True, the training dataloader preserves sequence order. PSANN disables shuffling whenever state_reset is "epoch" or "none" so stateful models consume contiguous batches; keep the default state_reset="batch" to retain randomised mini-batches.

Docs and examples

• Examples live in examples/; see docs/examples/README.md for the curated list (supervised, streaming, HISSO, benchmarks, diagnostics).
• Detailed internals are captured in TECHNICAL_DETAILS.md.
• Reward registry usage and custom strategy registration are described in docs/API.md under the HISSO section.

Current status and roadmap

• Predictive extras and growth schedules are gone; legacy extras_* arguments are accepted but ignored with warnings for backward compatibility.
• Terminology has converged on transition_penalty within HISSO; the trans_cost alias still functions but will be removed in a later release.
• CPU benchmarks run in CI; GPU baselines remain on the roadmap once shared hardware is available.
• Upcoming work highlighted in REPO_CLEANUP_TODO.md includes broader reward coverage, lint/type sweeps, and release tooling improvements.

Reproducibility

The notebook PSANN_Parity_and_Probes.ipynb (now under notebooks/) reproduces all key results under compute parity.

• Release: v1.0.0
• DOI: doi.org/10.5281/zenodo.17391523
• Permalink: GitHub
• Render: nbviewer
• Run:

Experiments used Python 3.9, dependencies pinned in pyproject.toml (install [compat] for constrained environments).