Dear QE developers, I would like to have your opinion on the procedure I followed in doing phonon calculations. I found that the use of nimages on my machine (8 numa zones) greatly improves the speed of some calculations, but the first (initialization?) part of the calculation (epsil=.true., i.e. the Electric Fields Calculation) is much faster when performed without the use of "-ni 8" switch in ph.x
So, I tested the following procedure and apparently worked for a small test crystal: 1) pw.x (vc-relax optimization) without using "-ni" 2) scf on the optimized structure containing "wf_collect=.true." and using "-ni 8" 3) ph.x containing "only_init = .true." and without using "-ni" This calculate the electric fields 4) duplicate the directory _ph0 and copied to _ph1 ... _ph7 (in output directory) 5) ph.x containing "recover = .true." and using "-ni 8" This is the part where I get most of the speedup 6) ph.x of the input used in 5), but now without using "-ni" This is to collect the partial data and produce the final .out I would greatly appreciate any comments in understanding if this procedure is correct. On a small crystal was working, but on a bigger crystal gave error. Either the procedure is not completely correct or I have to start to look for a problem in the RAM... Thank you, Carlo -- ------------------------------------------------------------ Prof. Carlo Nervi [email protected] Tel:+39 0116707507/8 Fax: +39 0116707855 - Dipartimento di Chimica, via P. Giuria 7, 10125 Torino, Italy. http://lem.ch.unito.it/
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