From NWChem
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9:26:52 PM PDT  Sun, Mar 31st 2019 

Hi all,
I'm working with a reaction (35 atoms total), which is only marginally within the limits of the hardware I presently have available.
From the documentation I've read, TCE can do ROHFCCSD in parallel but not CCSD[T]. If there's a way to do ROHFCCSD[T] in parallel please disabuse me of the misunderstanding and enlighten me as to how.
What I'd like to do (given the above assessment) if possible, is to run the ROHFCCSD in parallel and restart on a single core to finish the CCSD[T].
Can it be done? How? Would using TCE_CUDA (haven't compiled it yet but could) bear on this at all either way?
In general, I'd also like to know if it's possible to restart CCSD calculations (gamess can from the F70 scratch file it produces)
Thanks in advance!




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6:42:36 PM PDT  Mon, Apr 1st 2019 

I use the following input and three cores to do the ROHF calculation of doublet CH free radical with NWCHEM 6.8
echo
start molecule
charge 0
memory ...
geometry units angstroms print xyz
symmetry c1
C ...
H ...
end
basis
end
SCF
doublet
ROHF
END
TCE
SCF
CCSD[T]
io ga
END
TASK TCE ENERGY
and find it can be finished without any problem
Singles contributions
Doubles contributions
CCSD(T)
Using plain CCSD(T) code
...
CCSD[T] correction energy / hartree = ...
CCSD[T] correlation energy / hartree = ...
CCSD[T] total energy / hartree = ...
CCSD(T) correction energy / hartree = ...
CCSD(T) correlation energy / hartree = ...
CCSD(T) total energy / hartree = ...
Cpu & wall time / sec ...
Parallel integral file used 3 records with 0 large values
I have also successfully finished ROHF CCSDT for it parallelly.
The initial geometry might need to be reoptimized.

Edited On 3:43:38 PM PDT  Thu, Apr 4th 2019 by Xiongyan21




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5:03:52 PM PDT  Tue, Apr 2nd 2019 

I recalculate it using the same input and four threads with NWCHEM 6.8 on Ubuntu18.04 and get
...
Iterations converged
CCSD correlation energy / hartree = ...
CCSD total energy / hartree = ...
Singles contributions
Doubles contributions
CCSD(T)
Using plain CCSD(T) code
..
CCSD[T] correction energy / hartree = ...
CCSD[T] correlation energy / hartree = ...
CCSD[T] total energy / hartree = ...
CCSD(T) correction energy / hartree = ...
CCSD(T) correlation energy / hartree = ...
CCSD(T) total energy / hartree = ...
Cpu & wall time / sec ...
Parallel integral file used 4 records with 0 large values
Thus, there is no problem to run this parallelly with NWCHEM 6.8.

Edited On 3:44:40 PM PDT  Thu, Apr 4th 2019 by Xiongyan21




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Posts 292


4:48:27 PM PDT  Wed, Apr 3rd 2019 

When spherical is used, the result on Ubuntu18.04 becomes
...
Singles contributions
Doubles contributions
CCSD(T)
Using plain CCSD(T) code
...
CCSD[T] correction energy / hartree = ...
CCSD[T] correlation energy / hartree = ...
CCSD[T] total energy / hartree = ...
CCSD(T) correction energy / hartree =
CCSD(T) correlation energy / hartree =
CCSD(T) total energy / hartree = ...
The repeated one gives
...
CCSD[T] correction energy / hartree = ...
CCSD[T] correlation energy / hartree = ...
CCSD[T] total energy / hartree = ...
CCSD(T) correction energy / hartree =
CCSD(T) correlation energy / hartree =
CCSD(T) total energy / hartree = ..
The two results can be called identical.

Edited On 3:19:14 PM PDT  Fri, Apr 5th 2019 by Xiongyan21



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