Sample Inputs CC

Sample inputs for general order coupled cluster theory

We assume that you have created an interface file from an external program (or use this input within the Molpro interface). In certain cases (FCIDUMP interface), you might need to add further orbital space definitions.

This is an input for CCSDT (name it, for instance, 'ccsdt.inp'):

general
 memmax=50000000
orb_space
 shell type=frozen 
method
 CC maxexc=3
calculate
 solve maxiter=60,conv=1d-6,maxsub=8

shell type=frozen will detect the required orbitals to be kept frozen. For the Molpro interface you can skip this line, as the information will be automatically provided by the interface file.

memmax=<value> gives the maximum allowed memory consumption in words (= 8 bytes). For the Molpro internal interface, this value is overridden by the settings transferred from Molpro.

Assuming that "gecco.x" is in your $PATH, run GeCCo by

gecco.x -m -l ccsdt.log ccsdt.inp > ccsdt.out & 

The log file may be discarded. It is quite messy, but may give some additional information in case of unexpected behavior.