Fix reordering Prisms for ProcessPerAlign

Issue/feature addressed

In NekMesh, process PerAlign sometimes failed because the IDs of the vertices of a prism is badly ordered.

Proposed solution

The function ReorderPrisms() should re-orders the IDs of the vertices of a prism from small to large. In a prism element, when one triangle face is reordered and the other face is wait to be re-ordered, the old way of sorting vertices failed.

Implementation

Use a lambda function to sorting the IDs of the vertices

Tests

Here is the case of a extruded naca. The linear mesh is generated using StarCCM++. Sometimes I got the following error where the orientation of triangles are not consistent. It worked after the fix.

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Notes

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Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).