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<div class="moz-cite-prefix">On 1/12/21 9:12 PM, Mainak Ghosh wrote:<br>
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<div dir="auto">Dear all
<div dir="auto"> In 'vc-relax' or 'relax' calculation for
getting better results i have to reduce the forc_conv_thr, but
it will take longer time to be completed. So,if i reduce this
threshold step by step say, i wanted the forc_conv_thr tobe
1.0D-5. I can get this result in two way. </div>
<div dir="auto"> Firstly, i can run a direct calculation where
this threshold is 1.0D-5.</div>
<div dir="auto"> Secondly, in frist run i can use 1.0D-2 as
the threshold value and use the output file for next step
input where i can use 1.0D-5 as forc_conv_thr.</div>
<div dir="auto"> Is these two things are identical ?</div>
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<p>The final result yes, but it will be faster, in total, to start
immediately with the smaller threshold as the algorithm uses the
minimization history.</p>
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cite="mid:CALi5NYw3KDeQqYc7A1A=UPc7_hcYdQ3UO4U8BN69_--mJUaxCQ@mail.gmail.com">
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<div dir="auto"> Another thing can i use LDA pseudopotential
with forc_conv_thr 1.0D-5 as trial run and use the output for
GGA-PBE xc functional input ?</div>
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<p>Yes, but I don't think you will save any time, GGA is only
marginally more expensive than LDA. You may do a pre-relax with a
lower cutoff or less k-points, again I seldom find this strategy
to be very practical. It also depend on the value you give to CPU
time with respect to human time</p>
<p>cheers<br>
</p>
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cite="mid:CALi5NYw3KDeQqYc7A1A=UPc7_hcYdQ3UO4U8BN69_--mJUaxCQ@mail.gmail.com">
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<div dir="auto">Thanks in advance.</div>
<div dir="auto"> Mainak Ghosh</div>
<div dir="auto"> University of
Calcutta,India</div>
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