Data and code for: A singular-subspace diagnostic for evaluation stability in the method of fundamental solutions

This record contains a minimal data-and-code packagesupporting the associated manuscript,“A singular-subspace diagnostic for evaluation stabilityin the method of fundamental solutions.” The package includes two MATLAB programs and numericaloutputs for aligned circular, phase-shifted circular,and Cassini-oval configurations, together with afixed-matrix evaluation-radius test at five radii. The CSV files support inspection of the reportedspectral diagnostics, restricted evaluation gains,precision comparisons, CGLS convergence, noisesensitivities, and supplementary projected-excitationdiagnostics. The final publication figures were prepared manuallyusing Igor Pro. The README describes the source filesand plotting variables. The MATLAB programs alsocontain diagnostic plotting routines, but these donot reproduce the exact layout of the finalpublication figures. Large saved models and trialwise iteration historiesare not included in this minimal release.Recomputing the numerical experiments requires MATLABand Symbolic Math Toolbox. See README.md for the directory structure, experimentsettings, file descriptions, reproduction instructions,and limitations.