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ccmaxit keyword not properly applied

  • richard.kang
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3 days 10 hours ago - 3 days 10 hours ago #1599 by richard.kang
ccmaxit keyword not properly applied was created by richard.kang
Hello,

This is a simple CCSDT calculation with a cc-pvtz.
I am new to MRCC so I apologize for apparent mistakes but I thought the ccmaxit keyword is supposed to increase the CC iterations upto whichever number I set. However, I wasn't able to adjust this number by setting this keyword though the energy decrease in CC iterations seems stable enough.
Is there a bug or am I using a wrong keyword?
Though the attached output is for CCSDT, the same issue was present for other cases such as CCSDTQP etc.

 

File Attachment:

File Name: mrcc_out.txt
File Size:49 KB


Thank you,
Richard
 
 
Last edit: 3 days 10 hours ago by richard.kang.

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3 days 4 hours ago #1600 by alex34
Replied by alex34 on topic ccmaxit keyword not properly applied
As far as I remember, at least for previous versions (I am not a developer), this keyword does not apply to higher-order CC. You should redefine the maxit variable in the source file MRCCCOMMON and compile the program yourself.
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  • nagypeter
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2 days 22 hours ago #1601 by nagypeter
Replied by nagypeter on topic ccmaxit keyword not properly applied
Dear Richard,

alex34 is correct, maxit of MRCCCOMMON govern the maxumimum number of itnerations, when ccprog=mrcc.
ccmaxit keyword works for the ccprog=ccsd code, that is up to CCSD(T).

Just a note, but the reason that you need so much interations is that you set extremely tight settings: itol=14
cctol=8
These settings do not allow CCSDT to stop until exteremely tight convergence. Fine if intentional, then the only option is increasing maxit in MRCCCOMMON

Best regards,
Peter
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1 day 12 hours ago #1602 by richard.kang
Replied by richard.kang on topic ccmaxit keyword not properly applied
Thank you so much for both responses!
I will first try with less tight settings (I was just using MINP from a previous member in the group) and try to adjust MRCCCOMMON if absolutely needed.

Sincerely,
Richard

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