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MPI and Quantum Espresso


Dear experts,

I am having difficulty using MPI from parallel studio cluster edition 2016 in conjunction with Quantum Espresso PWSCF v 6.3. 

I think the problems may be inter-related and are to do with MPI-communicators. I compiled pw.x with Intel compilers, with Intel MPI, Intel ScaLapack and MKL, but without OpenMP.

I have been running pw.x with multiple processes quite successfully, however when the number of processes is high enough, such that the space group has more than 7 processes, where the subspace diagonalization no longer uses a serial algorithm, the program crashes abruptly at about the 10th iteration with the following errors;

Fatal error in PMPI_Cart_sub: Other MPI error, error stack: PMPI_Cart_sub(242)...................: MPI_Cart_sub(comm=0xc400fcf3, remain_dims=0x7ffe0b27a6e8, comm_new=0x7ffe0b27a640) failed PMPI_Cart_sub(178)...................: MPIR_Comm_split_impl(270)............: MPIR_Get_contextid_sparse_group(1330): Too many communicators (0/16384 free on this process; ignore_id=0) Fatal error in PMPI_Cart_sub: Other MPI error, error stack: PMPI_Cart_sub(242)...................: MPI_Cart_sub(comm=0xc400fcf3, remain_dims=0x7ffefaee7ce8, comm_new=0x7ffefaee7c40) failed PMPI_Cart_sub(178)...................: MPIR_Comm_split_impl(270)............:

On the pw forum, I got this response;

'a careful look at the error message reveals, that you are running out of space for MPI communicators for which a fixed maximum number (16k) seems to be allowed. this hints at a problem somewhere that communicators are generated with MPI_Comm_split() and not properly cleared afterwards.'

But I don't know how to fix this..

Please kindly advise,

Many thanks

Alex Durie

PhD student

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3 Replies

Do you get the same error with the 2018 or 2019 versions?

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Apologies if this is a repost:

Hi James T,


I'm afraid I am not the administrator of this machine so am unable to put the newer software on. On my own PC I have been running Quantum Espresso with the 2019 version without difficulty. I believe (without validation) that the errors exist as I have built the software in a directory that may not be accessible by all Intel Xeon blades. I am trying the administrators to build it in an alternative location. Do the errors included in my original post back my theory up?


Many thanks,



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Dear alex, Have you got a solution to the problem? I encounter the same problem with intel2018 on Quantum Espresso6.7. I'm not an expert on computer, and get no clue after googling for days. Can you give me some advice? Best regards, JqHuang
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