<div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Hi all!</div><div><br></div><div>I am performing a scaling test with QE (versions 6.1 and 6.3) for a big sistem >2000 electrons with GGA/USPP. I found that when I use more than one node the use of -nt is very usefull to improve the calculation time. For this system nt=number of nodes is the best choise in most cases... but sometimes nt = number of nodes + X, with X = 1,2,3,4... (no more than 4) is better. As an example, if i use 440 processors, with 44 processors nodes, the best nt is 11.</div><div>Also, I read that the -nt is usefull when the FFT 3D grid < n° processors, but in some cases when FFT 3D grid > n° processors, -nt 2 or 3 improves the calculation too.<br></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">Can someone help me with this topic, give me more information and internalize me in this topic?</span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">On the other hand, I try this with hybrid functional in a simple semiconductor sistem with ~50 atoms with HSE/NCPP. With 6.1 version the calculation CRASH when I use -nt 2, the error message is:</span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">     iteration #  1     ecut=    80.00 Ry     beta=0.30<br>     Davidson diagonalization with overlap<br>     ethr =  1.00E-02,  avg # of iterations =  8.0<br><br>     negative rho (up, down):  1.101E-01 0.000E+00<br><br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>     Error in routine electrons (1):<br>     charge is wrong: smearing is needed<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br>     stopping ...<br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">When I use smearing:</span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">     iteration #  1     ecut=    80.00 Ry     beta=0.30<br>     Davidson diagonalization with overlap<br>     ethr =  1.00E-02,  avg # of iterations =  8.0<br><br>     negative rho (up, down):  1.081E-01 0.000E+00<br><br>     total cpu time spent up to now is       24.5 secs<br><br>     WARNING: integrated charge=   312.31515712, expected=   320.00000000<br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>     Error in routine electrons (1):<br>     charge is wrong<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br>     stopping ...<br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">It is very weird, and with 6.3 version the calculation runs without problem, but take more time, and the speedup is very very low in comparison with one node calculation.</span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">There is a bug in 6.1 version? Is it a bug in the 6.1 compilation?</span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">Somebody knows some method to accelerate the hybrid calculations to be able to occupy more nodes?</span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">Regards</span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">Lucas Lodeiro</span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-">Universidad de Chile<br></span></span></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></div><div><span class="gmail-tlid-translation gmail-translation" lang="en"><span title="" class="gmail-"><br></span></span></div></div></div></div>