i-PI 2.0 is not always working as expected with Quantum Espresso 6.1 or 6.2.1

[Arpan Kundu]

Dear All,

I am a new i-PI user and I am facing some Quantum Espresso version related problem whenever I wanted to use it as a driver for i-PI.

 

I compiled QEspresso-6.1 with openMPI (version 1.10.2) and gfortran/gcc on my personal computer (OS: Ubuntu 16.04). I downloaded i-PI from the github and the used the supplied executable to run the following example: i-pi/examples/qespresso/h2o. Apparently, this exercise is running perfectly on my personal computer.

Motivated with that, I wanted to repeat the same exercise on our HPC (https://rcc.uchicago.edu/support-and-services/midway2). Whenever, I tried to run i-PI with Espresso-6.1 (gfortran+gcc+openMPI) drivers; it failed with the following error message:

"Error opening INET socket: wrong port or server unreachable: Connection refused"

I am getting the same error for Espresso-6.1/6.2.1 compiled with intelmpi and intel compilers.

However, with Espresso-6.4 (intelmpi + intel compilers) as a driver, apparently i-PI is working fine on HPC. 

I am a bit surprised by this apparently contradicting observation; and curious to know why as an i-PI driver Espresso-6.1 is not working on HPC but working perfectly fine on my personal computer.  It is possible that I am doing a silly mistake somewhere. If somebody can enlighten me regarding this, I will be grateful.

 

Thanks,

Arpan

 

[Kai Luo]

Hi Arpan,

As a preliminary answer, do you check the hostname and port number in the input to be the same as supposed to be? 

(it says: The group ipi-...@googlegroups.com does not allow posting through email. So I reply here again.)

Best,

Kai

[Michele Ceriotti]

Running on HPC systems can be a pain, but the fact you *can* get it to work with the intelmpi compiled executable makes me think this might have to do with the libraries more than with i-PI, Q-E, or the inputs you are using. 

Unfortunately it's basically impossible to help you debug this without having access to the HPC system where you're running - if you can live with QE 6.4 I'd say to just go with it.