<p dir="ltr">1. Use Gamma point if you can<br>
2. Use band parallelization<br>
3. Use a reduced cutoff for the calculation of the exchange term (ecutfock, can be reduced from its default value 4*ecutwfc with little loss of accuracy)<br>
4. Experiment with smaller systems.</p>
<p dir="ltr">Paolo</p>
<div class="gmail_extra"><br><div class="gmail_quote">Il 10/ago/2016 09:01 PM, "Narendranath Ghosh" <<a href="mailto:ghosh.naren13@gmail.com">ghosh.naren13@gmail.com</a>> ha scritto:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><span style="color:rgb(0,0,0);font-family:"times new roman",serif;line-height:18.2px">Dear </span><span style="color:rgb(0,0,0);font-family:"times new roman",serif;font-size:12.8px"><b>Dario</b>  t</span><font color="#000000" face="times new roman, serif"><span style="line-height:18.2px">hank you for  your continuous supports and help.</span></font><div><font color="#000000"><span style="font-family:"times new roman",serif;line-height:18.2px">Dear </span><span style="font-family:"times new roman",serif;line-height:18.2px"><b>Prof.  Paolo</b></span><span style="line-height:18.2px"><font face="times new roman, serif"><b> </b>Thank you for your suggestions. <b>"</b></font></span></font><font face="times new roman, serif"><span style="font-size:12.8px"><b>but it is hard and you </b></span><span style="font-size:12.8px"><b>have to know a number of tricks "</b>  Could you suggest me <b>some of the tricks</b> in this regard.</span></font><div><p style="color:rgb(80,0,80);font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><br></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><font color="#000000"><b><span style="font-family:"times new roman",serif">Narendra Nath Ghosh</span></b><span style="font-family:"times new roman",serif"></span></font></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><font color="#000000"><b><span style="font-family:"times new roman",serif">Research Associate</span></b><span style="font-family:"times new roman",serif"></span></font></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><font color="#000000"><b><span style="font-family:"times new roman",serif">University of Gour Banga</span></b><span style="font-family:"times new roman",serif"></span></font></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><b><span style="font-family:"times new roman",serif"><font color="#000000">Department of Computational Physics </font></span></b></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><font color="#000000"><b><span style="font-family:"times new roman",serif">Malda-732102</span></b><span style="font-family:"times new roman",serif"></span></font></p><p style="font-size:12.8px;margin-bottom:0.0001pt;background-image:initial;background-repeat:initial"><b><span style="font-family:"times new roman",serif"><font color="#000000">India</font></span></b></p></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 10, 2016 at 1:19 PM, Narendranath Ghosh <span dir="ltr"><<a href="mailto:ghosh.naren13@gmail.com" target="_blank">ghosh.naren13@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div><div><div dir="ltr"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 10, 2016 at 12:34 PM, Paolo Giannozzi <span dir="ltr"><<a href="mailto:p.giannozzi@gmail.com" target="_blank">p.giannozzi@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><span>On Tue, Aug 9, 2016 at 12:04 PM, Narendranath Ghosh<br>
<<a href="mailto:ghosh.naren13@gmail.com" target="_blank">ghosh.naren13@gmail.com</a>> wrote:<br>
<br>
>      EXX: now go back to refine exchange calculation<br>
<br>
</span>is this the first time this message appears? if so, nothing strange:<br>
when the code turns exact exchange on, the amount of required time<br>
grows enormously. It is possible to perform hybrid calculations in<br>
systems containing up to a few hundreds atoms, but it is hard and you<br>
have to know a number of tricks. The next version of QE will perform<br>
better.<br>
<br>
Paolo<br>
<span><br>
><br>
> Please suggest any idea.......<br>
><br>
> Narendra Nath Ghosh<br>
><br>
> Research Associate<br>
><br>
> University of Gour Banga<br>
><br>
> Department of Computational Physics<br>
><br>
> Malda-732102<br>
><br>
> India<br>
><br>
><br>
><br>
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</span><span><font color="#888888">--<br>
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
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