The following problem is observed using Paraview 5.5.1. The attached file defines a single-cell quadrilateral grid. The Geometry is specified using separate arrays for each coordinate (X_Y_Z). This loads just fine with the version 2 reader, but fails with the XDMF3 reader with the following segfault:
Skipping unrecognized array type [None]
Segmentation fault (core dumped)
bad_xyz.xdmf (712 Bytes)
Your .xdmf file does not validate against Xdmf.dtd
bad_xyz.xdmf:5: element Topology: validity error : No declaration for attribute NumberOfElements of element Topology
Once again, it looks like Xdmf2 reader may be just more lenient here.
The segfault is still not good anyway, and should be fixed.
@mwestphal The NumberOfElements attribute of the Topology element is copied directly from an example in the xdmf documentation
<Topology TopologyType="Quadrilateral" NumberOfElements="2">
<DataItem Format="XML" DataType="Int" Dimensions="2 4">
[...]
</DataItem>
</Topology>
So either the doc is wrong, or the DTD. Still, when I remove this attribute, nothing changes in Paraview’s behavior:
Skipping unrecognized array type [None]
Segmentation fault (core dumped)
bad_xyz_fix1.xdmf (691 Bytes)