<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">Hi,<br><br><div>You can use options in ph.in file: start_q=5, last_q=5 to calculate phonons for particular q-point(s) from the mesh.<br>The result should not depend on the way how you got these dyn-files (supposing all parameters are the same and correct). <br><br>The way you used is more convenient for a general q-point not presented in q-mesh.<br><br>Bests,<br>Eyvaz.<br></div>-------------------------------------------------------------------<br>Prof. Eyvaz Isaev, <br>Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <br>Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <br>isaev@ifm.liu.se, eyvaz_isaev@yahoo.com<div><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div
style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Bipul Rakshit <bipulrr@gmail.com><br><b><span style="font-weight: bold;"> </span></b></font><br><br> <b><span style="color: rgb(51, 51, 255);"> Dynamical matrices for ( 6, 6, 1,) uniform grid of q-points</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);"> ( 7q-points):</span><br style="color: rgb(51, 51, 255);"><span style="color: rgb(51, 51, 255);"> N xq(1) xq(2) xq(3)</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);"> 1 0.000000000 0.000000000 0.000000000</span><br style="color: rgb(51, 51, 255);"><span style="color: rgb(51, 51, 255);"> 2 0.000000000 0.192450090 0.000000000</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);"> 3 0.000000000 0.384900179 0.000000000</span><br style="color: rgb(51, 51, 255);"><span style="color: rgb(51, 51, 255);"> 4 0.000000000 -0.577350269 0.000000000</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);"> 5 0.166666667 0.288675135 0.000000000</span><br style="color: rgb(51, 51, 255);"><span style="color: rgb(51, 51, 255);"> 6 0.166666667 0.481125224 0.000000000</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);"> 7 0.333333333 0.577350269 0.000000000</span><br style="color: rgb(0, 0, 153);"></b><br>in my output file.<br>I just want to ask, that is it wise to run the calculation using<span style="color: rgb(204, 102, 0);"> ldisp =true</span> (<span style="color: rgb(255, 0, 0);"><a rel="nofollow" target="_blank" href="http://graph.ph.in">graph.ph.in</a></span>), which calculate the phonon frequencies one by one or <br>
<br>Seven different calculations, using the above seven different q-points, using single q-point calculation (<span style="color: rgb(255, 0, 0);"><a rel="nofollow" target="_blank" href="http://graph-singleq.ph.in">graph-singleq.ph.in</a>)</span><br style="color: rgb(255, 0, 0);">
<br>Is both the ways gives final result same?<br><br>Because the latter method takes less time, than previous.<br><br><br>thanks<br><br><br><br clear="all"><br>-- <br>Bipul Rakshit<br>Research Fellow,<br>S N Bose Centre for Basic Sciences,<br>
Salt Lake,<br>Kolkata 700 098<br>India<br>
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