XPCS Viewer Documentation¶

XPCS Viewer is a Python toolkit for X-ray Photon Correlation Spectroscopy (XPCS) data analysis. It provides a PySide6 GUI and Python API for loading, visualizing, and fitting XPCS correlation functions from HDF5 data files.

At a Glance¶

Analysis	G2 correlation (g2, g2 Fit, g2 Map), SAXS 1D/2D, two-time correlation, stability, diffusion
Fitting	NLSQ 0.6.0 point estimates + NumPyro NUTS Bayesian inference with ArviZ diagnostics
Backends	NumPy (default) and JAX (GPU acceleration, JIT, gradients)
Mask Editor	Interactive mask creation, Q-map generation, and Q-phi partitioning
Data Format	HDF5 (NeXus convention) with schema-validated I/O
GUI	PySide6 with light/dark themes, SVG icons, category tab bar, command palette, session persistence

Key Features¶

Correlation Analysis: G2 autocorrelation across dedicated tabs (g2 view, g2 Fit, g2 Map), two-time methods, SAXS 1D/2D visualization, sample stability monitoring, and diffusion coefficient extraction
Fitting Pipeline: NLSQ warm-start followed by NumPyro NUTS sampling. Model selection via AIC/BIC, prediction intervals, and ArviZ convergence diagnostics (R-hat, ESS, BFMI)
Backend Abstraction: Unified NumPy/JAX API with automatic fallback. JIT compilation and GPU acceleration for compute-intensive operations. ensure_numpy() at I/O boundaries
Interactive Mask Editor: Drawing tools (Rectangle, Circle, Polygon, Line, Ellipse, Eraser) with undo/redo history, Q-map computation from detector geometry, and Q-phi partition export

Quick Start¶

# Install
pip install xpcsviewer-gui

# Launch GUI
xpcsviewer-gui /path/to/hdf/data

# CLI batch processing
xpcsviewer twotime --input /data --output /results --q 0.05

from xpcsviewer import XpcsFile

# Load XPCS data
with XpcsFile("data.hdf") as xf:
    q, t_el, g2, g2_err, labels = xf.get_g2_data()
    print(f"Q bins: {len(q)}, Delay points: {len(t_el)}")