Hi, I've been trying to implement code using MPI_Get and MPI_Put that move around data using MPI_Datatypes. If I create the data type using MPI_Type_create_subarray, everything works fine. If I create the data type using MPI_Type_create_struct then I get a failure if the amount of data I'm moving around becomes large. At the moment the crossover point is moving a total of a million doubles on 8 cores (125000 doubles per core), which doesn't seem to be excessively large. The error I'm seeing on a Linux cluster using and Infiniband interconnect is Assertion failed in file ./src/mpid/ch3/channels/nemesis/include/mpid_nem_inline.h at line 406 : MPID_NEM_MPICH_DATA_LEN - buf_offset >= ext_hdr_sz internal ABORT - process 1 Note that the same code runs fine if the data type is created using the subarray call. It looks like some internal limit is being exceeded, but if so, I think the threshold may be set a bit on the low side. Does anyone know more about this? Bruce Palmer _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss