wwinp files: Fix MemoryError in WeightWindowsList.export_to_hdf5 and speed up from_wwinp. Alternative Approach#3951
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yrrepy wants to merge 22 commits into
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wwinp files: Fix MemoryError in WeightWindowsList.export_to_hdf5 and speed up from_wwinp. Alternative Approach#3951yrrepy wants to merge 22 commits into
yrrepy wants to merge 22 commits into
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Float/complex ndarrays are dtype-validated, so the per-element isinstance() scan is redundant. Also construct upper_ww_bounds in WeightWindows.__init__ as an ndarray multiplication (not a list comprehension) so the upper-bounds setter benefits too. ~11x speedup on 172M-element wwinp inputs (397 s -> 35 s).
The XML serialization raised MemoryError on bound arrays >~200M elements -- lxml's intermediate ASCII allocation fails before the text node can be built. Write HDF5 directly via h5py, mirroring the C++ WeightWindows::to_hdf5 writer. Critical details for C++ compatibility: - Bounds are 2D (ne, n_voxels) on disk (4D would segfault the C++ tensor::Tensor<double> reader). - max_lower_bound_ratio is written unconditionally (default 1.0). - Root attrs filetype and version are required by openmc_weight_windows_import. Adds Mesh.to_hdf5 on each structured mesh subclass, mirroring the existing Mesh.to_xml_element pattern. UnstructuredMesh raises NotImplementedError (wwinp cannot produce one).
The dtype-trust fast path returned for any float/complex ndarray of matching depth, even when expected_type was int or another class -- the docstring promised element-type validation but the fast path skipped it. Gate the fast path on expected_type in (Real, float, complex) so it only fires when dtype.kind in 'fc' actually satisfies the contract.
The direct-h5py writer cannot serialize an UnstructuredMesh from pure Python: vertex and connectivity data live in the external .exo/.h5m file and only exist in memory after LibMesh/MOAB loads them via openmc.lib.init. Dispatch on mesh type up front: structured meshes take the new fast path; UnstructuredMesh falls back to the previous TemporarySession + openmc.lib.export_weight_windows route, which also restores honoring of init_kwargs on that path. Removes the dead NotImplementedError branch from _write_mesh_group.
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GuySten
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May 30, 2026
Declaring to_hdf5 as an abstractmethod documents that every mesh type implements it
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Closed #3942
in favor of the alternative approach, (this PR).
Switching to the per-mesh
Mesh.to_hdf5design, each mesh subclass serializes itself, mirroring the existingto_xml_elementsuper-call pattern) instead of a central dispatch helper.This PR:
This enables support for many-GB wwinp files and faster processing of them.
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