Spectrum Viewer: Fitting Quality (Chi sq)

[ashleymeigh2]

Current Behaviour

The Spectrum Viewer GUI allows users to apply fitting models to spectral data over a selected ROI. While parameter values are displayed after fitting, there is no quantitative feedback indicating how well the fit matches the data. Users rely entirely on visual judgment.

Desired Behaviour

Display the fit quality using a Chi² metric (sum of squared residuals) immediately beneath the fitted parameters in the GUI.

Importance of Feature

Provides a standard, objective measure of fit quality. Aids users in assessing and refining fits without relying on visuals alone.

Additional Context

Inspired by functionality in NEAT_v4.5.3_beta.py on GitHub
(Ray Zhang, 2024).

[samtygier-stfc]

We should confirm with IMAT if they like to have the Reduced chi-squared statistic, with residuals divided by the variance. There is already some code to calculate this, as it was used for the RITS export.

We could possibly have a user choice of which to show.