I noted that a similar question has been asked by others before, but there is no good answer found yet:
I have been doing a comparison on the performances and resource demands of CCSD various software package; I found that NWChem may give different CCSD energies for using the TEC and legacy CCSD algorithm, and I reproduced the number generated by the legacy CCSD code by other commercial packages. Can anyone provide some advice?
The code was download and compiled on 16May2019, using intel compiler, mpi and mkl (2017), the armci_network used is mpi-pr, and ga version is 5.7.0
The summary of outputs and input are given as follow:
Legacy CCSD:
-------------------------------------------------------------------------
iter correlation delta rms T2 Non-T2 Main
energy energy error ampl ampl Block
time time time
-------------------------------------------------------------------------
g_st2 size: 12 MB
mem. avail 10099 MB
1 -0.8027540481 -8.028D-01 1.771D-01 4.70 0.00 4.36
...
11 -0.8316067315 -2.419D-07 4.788D-07 1.72 0.00 1.46
*************converged*************
-------------------------------------------------------------------------
-----------
CCSD Energy
-----------
Reference energy: -230.711542913190101
CCSD corr. energy: -0.831606731454189
Total CCSD energy: -231.543149644644302
TCE CCSD:
CCSD iterations
-----------------------------------------------------------------
Iter Residuum Correlation Cpu Wall V2*C2
-----------------------------------------------------------------
1 0.2204269357423 -0.8055763310885 5.2 1.4 0.8
...
35 0.0000000000008 -0.8473895042521 4.0 1.0 0.7
-----------------------------------------------------------------
Iterations converged
CCSD correlation energy / hartree = -0.847389504252062
CCSD total energy / hartree = -231.558932417442151
The input for NWChem:
memory stack 10000 mb heap 100 mb global 10000 mb noverify
start benzene
geometry
SYMMETRY c1
C 0.00000 1.40272 0.00000
H 0.00000 2.49029 0.00000
C -1.21479 0.70136 0.00000
H -2.15666 1.24515 0.00000
C -1.21479 -0.70136 0.00000
H -2.15666 -1.24515 0.00000
C 0.00000 -1.40272 0.00000
H 0.00000 -2.49029 0.00000
C 1.21479 -0.70136 0.00000
H 2.15666 -1.24515 0.00000
C 1.21479 0.70136 0.00000
H 2.15666 1.24515 0.00000
end
basis cartesian
* library 6-31g**
end
driver
clear
end
scf
singlet
VECTORS HCORE
THRESH 1.0e-9
maxiter 90
end
ccsd
maxiter 100
TOL2E 10e-12
FREEZE atomic
end
TCE
FREEZE atomic
ccsd(t)
thresh 1.0e-12
io ga
tilesize 18
END
task ccsd(t) energy
task tce energy
set tolguess 1e-7
set tce:xmem 100
Regards,
Dominic Chien
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