Hi Rob, I've facing similar issue as naibaf where i'm trying to access c_udmi value in the exterior cell of a partition. My intention is to calculate the average value of C_UDMI for a cell_t c at thread t based on the neighboring cell (if the given cell_t c has 6 faces, that means it has 6 neighboring cells). The averaging function works if the cell zone was in the same partition, but will give the wrong value if the cell zone have more than one partition.
Below images is the correct contour of user defined memory as the cell zone is not separated by any partition.
Below is the wrong contour (wrong averaging calculation) as the cell zone was splitted into two different partition.
Is there a way to access user defined memory on the exterior cell of a partition mesh so that i could get the averaging calculation right. 
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