From: Diego on
There is an error at the assempde help topic.
At the end of the topic the exemple says that the pde coefficient is:
c = 'c1111|0|c1122|0|c1221|0|c1212|c2211|0|c2222';
but the correct would be:
c = 'c1111|0|c1122|0|c1221|c1212|0|c2211|0|c2222';
I hope it helps,

Diego C.