Diffuse Scattering Troubleshooting

Start With The Smallest Stable Example

If the tool appears unstable, start with LiFeO2.rmc6f and moderate grid spacing before moving to the larger or more complex examples.

WebGPU Does Not Work

• Use a recent Chromium-based browser with WebGPU enabled.
• If WebGPU is unavailable, switch the backend to CPU FFT.
• For verification runs, CPU FFT is the preferred fallback.

Results Differ Between Backends

• The WebGPU FFT/NUFFT stack and the CPU FFT path use fp32 arithmetic and do not provide fp64 execution.
• Small numerical differences or precision-related artifacts can appear for large grids, high dynamic range, or cancellation-sensitive features.
• For important checks, compare against type3NufftCpuDirect.
• If the interpretation changes with backend or grid density, treat that result cautiously.

Runs Are Slow Or Too Large

• Increase the grid step.
• Reduce the reciprocal-space range.
• Switch from WebGPU to CPU FFT only if debugging a backend-specific problem.
• Use LiFeO2.rmc6f or CaTiO3.rmc6f before attempting PMN.

2D Slice Looks Hard To Interpret

• Reset the slice and color levels.
• Start with axis mode, then move to normal-plane mode.
• Use the examples guide to understand which feature families to expect in each sample.

Scattering Model Confusion

• Use the scattering type/model controls to match the experimental modality.
• Neutron, X-ray, and electron settings are not interchangeable.
• For published scientific interpretation, always record which scattering option was used.

Exports

If a plot export is disabled, compute the diffuse volume first. Slice and 3D export actions are tied to available results and active views.