Reading different Functions with different names into .pvd causes VTK-error

[Øyvind Evju]

When trying to read a .pvd file in ParaView that has been created from different named functions, it fails with the following error:

paraview: /build/buildd/paraview-3.98.0/VTK/IO/XML/vtkXMLDataReader.cxx:355: virtual void vtkXMLDataReader::SetupOutputData(): Assertion `this->NumberOfPointArrays == this->PointDataArraySelection->GetNumberOfArraysEnabled()' failed.

Functions are given different names by default. My suggestion is to either give a different default name to Function than e.g. "f_48", or keep track of the Function-names written to pvd-files.

Attached is pvd and vtu files to reproduce the error, produced without specifying Function name.

[Johan Hake]

This is not a bug report. What you suggest is a best user practise to avoid problem with different named function and ParaView. It fits better at fenicsproject.org/qa