Data and Fitting

This section covers the practical workflow: loading XPCS data, choosing the right analysis mode, running NLSQ optimization, and interpreting results.

• Loading XPCS Data
  • Overview
  • HDF5 File Requirements
  • Basic Usage
  • Loaded Data Dictionary
  • YAML Configuration for Data Loading
  • Multiple q-Values
  • Phi Angle Filtering
  • Data Validation
  • Common Data Issues and Fixes
  • Supported File Formats
  • See Also
• NLSQ Fitting Guide
  • Overview
  • Complete Workflow
  • The fit_nlsq_jax Function
  • Understanding the Result Object
  • NLSQAdapter vs NLSQWrapper
  • Memory-Adaptive Strategy Selection
  • Setting Initial Parameters
  • Multi-Start Optimization
  • Convergence Diagnostics
  • Common Fitting Issues
  • See Also
• Choosing Your Model
  • Overview
  • Decision Guide
  • Memory Considerations
  • Performance Benchmarks
  • Anti-Degeneracy System
  • See Also
• Interpreting Results
  • NLSQ Result Structure
  • Reduced Chi-Squared Interpretation
  • Parameter Uncertainties
  • Residual Analysis
  • CMC Result Structure
  • Convergence Diagnostics
  • Saving and Loading Results
  • See Also

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What you will learn:

• How to prepare and load HDF5 two-time correlation data.

• How to run NLSQ fitting for static and laminar flow modes.

• How to select between static and laminar flow analysis modes.

• How to interpret optimization results, chi-squared, and uncertainties.

Prerequisites: Fundamentals and a working Homodyne installation (Installation).