- GridParallelRNG must be constructed on full (non-checkerboarded) UGrid,
not UrbGrid; fill() recurses infinitely when _grid is checkerboarded.
- evec and c_srcs for ImplicitlyRestartedBlockLanczosCoarse must both be
on f_grid (Coarse4d), not CoarseMrhs; calc_irbl asserts evec[0].Grid()
== src[0].Grid().
- Switch subspace generation from CreateSubspaceChebyshevNew to
CreateSubspace (CG inverse iteration), which requires no spectral
bound tuning and adapts automatically to the matrix spectrum.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Thomas Blum
905651deaa