
Keyword  Meaning 
TITLe  This keyword is followed by one title line. 
FROZen  Integer on the following line specifies number of inactive occupied orbitals in the CCSD calculation. (Default=0) 
DELEted  Integer on the following line specifies number of inactive virtual orbitals in the CCSD calculation. (Default=0) 
LARGe  Integer on the following line specifies the main segmentation of the virtual orbitals. Value must be between 1 (no segmentation) and 32. Product of Large and Small segmentation must be lower than 64. (Default=1) 
SMALl  Integer on the following line specifies the auxiliary segmentation of the virtual orbitals. Value must be between 1 (no segmentation) and 8. Product of Large and Small segmentation must be lower than 64. Small segmentation doesn't generate extra parallel tasks. (Default=1) 
CHSEgmentation  Integer on the following line specifies the block size of the auxiliary (Cholesky/RI) index. Value must lower than the minimal dimension of the auxiliary index on each computational node. (Default=100) 
MHKEy  Integer on the following line specifies if library BLAS (MHKEy=1) or hardcoded fortran vectorvector, matrixvector and matrixmatrix manipulation is used. (Default=1) 
NOGEnerate  This keyword specifies that the preCCSD steps (regeneration of integrals from the Cholesky/RI vectors, etc.) are skipped. (Default=OFF) 
ONTHefly  This keyword specifies that all integral types scaling steeper then O^{2}V^{2} are generated "onthefly" from the Cholesky/RI vectors. Use of this keyword leads to dramatically savings of the disk resources, but leads to significant arithmetic overhead. Keywords "ONTHefly" and "PRECalculate" are mutually exclusive. (Default=OFF) 
PRECalculate  This keyword specifies that all integral are precalculated before the CCSD iterative procedure starts. Use of this keyword leads to significant consumption of the disk space, especially is singleprocessor runs. (Default=ON) 
NODIstribute  This keyword (in combination with the "PRECalculate" keyword) specifies that all integral are stored on each computational node. In case of all integrals being stored on each node, extra permutation symmetry can be applied, thus leading to significant savings of the disk space. However, in case of massively parallel runs (i.e. more than 8 nodes), savings from keeping only subset of integrals required on particular node are more significant than savings due to permutational symmetry. (Default=OFF) 
JOINlkey  The parameter on the following line specifies, which algorithm is used for
precalculation and of the integrals in parallel run. In parallel runs, SEWARD
produces AO Cholesky/RI vectors segmented in auxiliary index over
parallel nodes. Depending on the network bandwidth and computational power
of each node, different algorithms can lead to optimal performance.
Following options are available:
0  None: no cumulation of Cholesky/RI vectors is needed (debug only). 1  Minimal: Cholesky/RI vectors are cumulated prior to integral precalculation. Low network bandwidth is required. 2  Medium: O^{2}V^{2} integrals are generated from local Cholesky/RI vectors and cumulated along with the Cholesky/RI vectors afterwards. Other integrals are calculated from cumulated intermediates. 3  Full: All integrals are generated from local Cholesky/RI vectors and cumulated afterwards. High network bandwidth is required. (Default=2) 
MAXIterations  Integer on the following line specifies maximum number of CCSD iteration (Default=40) 
RESTart  This keyword specifies that CCSD calculation is restarted from previous run. This keyword is currently under development, thus disabled. (Default=OFF) 
THREshold  Double precision floating point number on the following line specifies the convergence threshold for the CCSD correlation energy. (Default=1.0d6) 
PRINtkey  The integer on the following line specifies the print level in output
1  Minimal 2  Minimal + timings of each step of the CCSD iterations 10  Debug (Default=1) 
END of input  This keyword indicates that there is no more input to be read. 
&CHCC &END
Title
Benzene dimer
Frozen
12
Deleted
0
Large
4
Small
2
CHSEgment
100
Precalculate
Join
2
Maxiter
50
Threshold
1.0d6
Print
2
End of Input