[QE-users] MPI errors specific to head.x

[Michal Krompiec]

Hello,
I'm using QE 6.5 build with Intel 2020 compilers and ELPA library. I
am seeing a weird MPI crash when running head.x (while every other
code in QE seems to run just fine!). I would be very grateful if
someone could point me in the right direction.
Abort(873024773) on node 0 (rank 0 in comm 0): Fatal error in
PMPI_Comm_size: Invalid communicator, error stack:
PMPI_Comm_size(110): MPI_Comm_size(comm=0x0, size=0x7ffdd7d69e50) failed
PMPI_Comm_size(67).: Invalid communicator
Error condition encountered during test: exit status = 5

When using QE 6.5 built with GCC 8.3 and Intel MKL 2020, head.x also
crashes, but only if the number of MPI processes is above 1, with this
message:
    Error in routine cdiaghg (44):
     S matrix not positive definite
When I run it with only 1 MPI process, it runs fine. Is there any
particular reason why head.x would not like to be MPI-parallelized?
Can it be because my system is rather small? (8 atoms, so same size as
"example05")

Best regards,
Michal Krompiec
Merck KGaA