<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Dear Dennis,<br>
<br>
the problem you encountered most likely arises from strongly
correlated CH-stretching vibrations. According to your output the
vibrational ground-state calculation succeeded without problems and
the next state to be computed is a CH-stretching mode. As you have 4
hydrogen atoms in your systems, these will be strongly coupled,
leading to very low leading VCI coefficients. As a consequence very
many configurations need to be selected to describe this state
properly. For example, if the selection process has picked more than
50.000 configurations (which would be just 5% of the original space)
the memory demands for the VCI matrix become huge. The newest (still
unreleased :( ) version of Molpro avoids this bottleneck by
exploiting sparsity techniques. The fact that the message provided
by Molpro states, that there a just 25 MByte left is a result of the
iterative nature of the algorithm, which steadily increases the
memory demands. It does not request the memory for the VCI matrix in
one piece. Essentially everything looks quite alright to me. <br>
<br>
What can you do? Make up your mind, if you really need the
CH-stretching vibrations. Very often, the fingerprint regions is
more important. If you do not need them, you can exclude them by
using the VIBSTATE program (do not forget the USERMODE option). If
you really need them, I suggest to switch to a calculation on just
one core and to provide about 2000 MW to the calculation. Most
likely this will do it, but definitely will take some time. You
could also try to reduce the correlation space in the VCI
calculation by reducing CIMAX and LEVEX keywords. This of course
will lead to less reliable results, but you will get a "feeling"
about the the problem. You may start with very small VCI spaces and
then you steadily increase the correlation space in order to
understand what's going on. <br>
<br>
I believe that this is not a technical problem, but rather a
molecule specific problem which arises from the strong couplings of
the CH-stretching modes. <br>
Best wishes,<br>
<br>
Guntram<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 08/29/17 11:36, Dinu, Dennis Florian
wrote:<br>
</div>
<blockquote
cite="mid:03DF623C9A80794AADC9AE820307C12669DE0648@XMBX2.uibk.ac.at"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<style type="text/css" id="owaParaStyle">P {margin-top:0;margin-bottom:0;}</style>
<div style="direction: ltr;font-family: Tahoma;color:
#000000;font-size: 10pt;">Dear Molpro-Community,<br>
<br>
first of all the SURF/VSCF/VCI programs in molpro perform really
nice, the majority of the anharmonic vibrational calculations
were unproblematic and all in all the experience was very
user-friendly. But now that I switched to a bigger System
(C2H4O3), I run into a memory problem, which I cannot solve from
the rather brief error output. <br>
<br>
Setup: precompiled Molpro 2015.1 / Intel Xeon CPU E5-2643 v3 /
12 cores / 256 GB RAM<br>
The error message: <br>
<font size="1">--------------------------------------------------------------------------------------------------<br>
PROGRAM * VCI (Vibrational configuration interaction)
Authors: G. Rauhut 2004, M. Neff 2009, D. Oschetzki 2013<br>
<br>
Reading potential from record 5600.2<br>
Reading wave function from record 5750.2<br>
<br>
Results of VCI calculation:<br>
<br>
Number of configurations: A` 1259812 ( S: 84
D: 3528 T: 91210 Q: 1164989 )<br>
A`` 1023169
( S: 21 D: 1722 T: 61740 Q: 959686 )<br>
<br>
Fundamentals<br>
<br>
Mode E(abs) VCISDTQ IR Intens Leading
term Type Dim. CPU tot. CPU #<br>
0 14548.94
0.00 0.9507
J 5721 11616.6 11616.6<br>
insufficient memory available - require
26270376 have <br>
25383256<br>
the request was for real words</font><br>
<font size="1">--------------------------------------------------------------------------------------------------<br>
<br>
</font>The calculation was started with 512 Megawords per CPU,
so the error message, saying that there are just about 25
Megawords available is rather strange for me. I already tried
much less (100 Megawords), and much more (1024 Megawords) memory
allocation per CPU, but with the same error message. <br>
<br>
There are some posts in the mailing-lists concerning this, most
of then within electronic structure theory. Here some examples:<br>
CASSCF calculation: <a moz-do-not-send="true"
href="http://www.molpro.net/pipermail/molpro-user/2005-June/001380.html"
target="_blank">
http://www.molpro.net/pipermail/molpro-user/2005-June/001380.html</a><br>
CCSD(T) calculation: <a moz-do-not-send="true"
href="http://www.molpro.net/pipermail/molpro-user/2009-June/003122.html"
target="_blank">
http://www.molpro.net/pipermail/molpro-user/2009-June/003122.html</a><br>
UCCSD(T)-F12 calculation: <a moz-do-not-send="true"
href="http://www.molpro.net/pipermail/molpro-user/2011-April/004320.html"
target="_blank">
http://www.molpro.net/pipermail/molpro-user/2011-April/004320.html</a><br>
and much more..<br>
<br>
The main answers that i found:<br>
1) Increase the memory until the calculation works.<br>
Question: For the CC programs, molpro suggests the amount of
memory it needs. Is there a similar output for the VCI progams?<br>
<br>
2) Adjust size of the shmmax kernel parameter in
/proc/sys/kernel/shmmax<br>
Question: For the MPI-2 version of molpro, this parameter should
not be of interest.. is that right?
<br>
<br>
Are there any other suggetions and answers to that problem?<br>
<br>
PS: On our large-memory nodes, we have no SWAP. Could that be a
problem for the molpro system?<br>
<br>
greets<br>
<br>
Dennis Dinu<br>
Institute of Theoretical Chemistry<br>
University of Innsbruck<br>
<br>
<br>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Molpro-user mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Molpro-user@molpro.net">Molpro-user@molpro.net</a>
<a class="moz-txt-link-freetext" href="http://www.molpro.net/mailman/listinfo/molpro-user">http://www.molpro.net/mailman/listinfo/molpro-user</a></pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
********************************************************************************
Apl. Prof. Dr. Guntram Rauhut
Institut f. Theoretische Chemie
Universitaet Stuttgart
Pfaffenwaldring 55
D-70569 Stuttgart
Germany
Tel. : +49/(0)711/685-64405
FAX : +49/(0)711/685-64442
E-Mail : <a class="moz-txt-link-abbreviated" href="mailto:rauhut@theochem.uni-stuttgart.de">rauhut@theochem.uni-stuttgart.de</a>
HTTP : <a class="moz-txt-link-abbreviated" href="http://www.uni-stuttgart.de/theochem/rauhut/">www.uni-stuttgart.de/theochem/rauhut/</a>
********************************************************************************
</pre>
</body>
</html>