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Hi Molpro Users,
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<div class="">I have run into the error same previously brought up by Artur Nenov (see email copied below), which arises in the RS2 routine when gradients are calculated. I have been unable to find further mention of it in the mailing list, and wanted to know
if there had been follow-up or if a work-around had been found. Can the threshold for matching E0 be tuned without recompilation?</div>
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<div class="">Many Thanks,</div>
<div class="">Seth</div>
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<div class="">******Original Message from Artur Nenov dated Oct 18 2011******</div>
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<pre style="white-space: pre-wrap; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">Dear Molpro developers,
I have encountered an error while trying an RS2 optimization in Molpro. It
occurs while Molpro tries to calculate the gradient in a SS-PT2 or MS-MR-PT2
step.
The error output reads
WRONG E0 FROM CIGAM0I: -34.84434593 -34.84434594 (exemplary numbers)
and comes after the RESULTS FOR STATE list. The values given after the error
message give the Zeroth-order valence energy, which is calculated once in the
begining of the RS2 routine (without level shift) and then recalculated when a
gradient calculation is requested (this time adding the level shift). The
error occurs also when no error shift given.
The error can be straced back to the files cigam2ppi.f (SS-PT2) and
cigam2ppi_ms.f (MS-MR-PT2), where an accuracy of 1.d-9 for the delta of both
values is needed, otherwise the program aborts. Obviously, in the given case
the delta is higher. I all situation where I had this error so far both values
differ by one or two digits in the very last printed decimal place. Further so
far this error has not occured with smaller molecules like ethylene or
cyclohexadiene, only with bigger molecules.
My question is whether these small discrepances between the Zeroth-order
valence energies before and after the PT2 correction are due to some numerical
inconsistence or there is more to it.
Can I ignore this error (comment the abortion execution signal in the two files
above) or reduce the accuracy? Is this error somehow connected to the accuracy
of the calculated gradient?
Best regards,
Artur Nenov
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<div class="">===========================
<div class="">Seth Olsen, PhD.</div>
<div class="">Honorary Fellow</div>
<div class="">School of Mathematics & Physics</div>
<div class="">The University of Queensland</div>
<div class="">QLD 4072 Australia</div>
<div class="">Ph: +61 7 3365 2816</div>
<div class="">===========================</div>
<div class="">A PGP public key for this address has been uploaded to the key servers.</div>
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