periodic + mesh.set_order fails on this example
On this geo file 4grains.geo the following python script
gmsh.initialize()
gmsh.open("4grains.geo")
gmsh.model.mesh.generate(3)
gmsh.model.mesh.set_order(2)
gmsh.write("4grains.msh")
fails with the error
Cannot find periodic counterpart of node 33 of surface 50 on surface 54
.
But this (from the user point of view, equivalent) script runs without error and produces a 2nd order mesh.
gmsh.initialize()
gmsh.open("4grains.geo")
gmsh.option.set_number("Mesh.ElementOrder", 2)
gmsh.model.mesh.generate(3)
gmsh.write("4grains.msh")