Apparent bug in MP3 portion of MP4 calculation


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Gets Around
It's not a bug in the traditional sense. It is a defect in how Moller-Plesset methods were implemented in TCE. For example, MP4 requires the storage of quadruples amplitudes. This is not necessary for canonical methods, but TCE was designed to be fully general, and such an approach may be required for nonorthogonal basis sets.

https://github.com/jeffhammond/nwchem/blob/master/QA/tests/tce_h2o/mp4sdq_h2o.nw demonstrates the "mbpt4sdq(t)" method, which is equivalent in cost to CCSD(T), as should be the case when RHF orbitals are used, and may be true to UHF and/or ROHF, but I have not verified. You can compare to GAMESS to know for sure.