Hello, I am looking at allgatherv.c from: git.mpich.org/mpich.git/tree/HEAD:/src/mpi/coll It says the following: "For short or medium-size messages and power-of-two no. of processes, we use the recursive doubling algorithm. ... For long messages or medium-size messages and non-power-of-two no. of processes, we use a ring algorithm. ..." Could someone please tell me what algorithm is used when we have "long messages and power-of-two no. of processes"? Thanks a lot! Best, Jen _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss