Architecture Deep Dives

This section collects detailed architecture documents for each major subsystem. These documents describe internal design decisions, data structures, and algorithmic details beyond what is covered in the Architecture Overview overview.

Subsystem Summaries

Heterodyne Architecture Overview

Top-level system design: package structure, module responsibilities, and the two-path integral architecture (meshgrid vs. element-wise).

Physical Model Architecture

The 14-parameter two-component correlation model: transport equations, velocity phase terms, sample fraction polynomials, and the unified HeterodyneModel facade.

NLSQ Fitting Architecture

Trust-region Levenberg–Marquardt implementation: JAX-JIT residual and Jacobian adapters, strategy selection by data size, sequential vs. direct modes, and convergence diagnostics.

CMC Fitting Architecture

Consensus Monte Carlo with NUTS: ShardGrid element-wise evaluation, reparameterized and non-reparameterized sampling paths, prior construction, and ArviZ post-processing.

Data Handler Architecture

HDF5 loading via XPCSDataLoader: shape/dtype validation, NaN guards, monotonicity checks, and cache management.