<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Is there any documentation about the -D__USE_3D_FFT option within Quantum Espresso PWscf? I couldn’t find any in the various manuals. In particular I’m interested to know whether this option is significant only for use with the internal FFT code provided with Quantum Espresso or also when using an external library for FFT (e.g. MKL). Any other information about the purpose/applicability/trade-offs involved in this option would also be very useful. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Paul.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>---<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>Paul Caheny<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>Researcher<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>Technical Computing Research<br>Fujitsu Laboratories of Europe Ltd (FLE)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>phone: +44 (0) 20 8606 4529<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>e-mail: <a href="mailto:Paul.Caheny@uk.fujitsu.com"><span style='color:#00B050'>Paul.Caheny@uk.fujitsu.com</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#00B050;mso-fareast-language:EN-GB'>web: <a href="http://www.fujitsu.com/emea/about/fle" target="_blank"><span style='color:#00B050'>http://www.fujitsu.com/emea/about/fle/</span></a><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>
<table><tr><td bgcolor=#ffffff><font color=#000000><pre>______________________________________________________________________
Fujitsu Laboratories of Europe Limited
Hayes Park Central, Hayes End Road, Hayes, Middlesex, UB4 8FE
Registered No. 4153469
This e-mail and any attachments are for the sole use of addressee(s) and
may contain information which is privileged and confidential. Unauthorised
use or copying for disclosure is strictly prohibited. The fact that this
e-mail has been scanned by Trendmicro Interscan does not guarantee that
it has not been intercepted or amended nor that it is virus-free.</pre></font></td></tr></table>