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PROGRAM:
NAME
chemps2 - spin-adapted DMRG for ab initio quantum chemistry
SYNOPSIS
chemps2 [OPTION] ...
DESCRIPTION
chemps2 is a scientific code to perform spin-adapted density matrix renormalization group
(DMRG) calculations for ab initio quantum chemistry fcidump files. This method allows one
to obtain numerical accuracy in active spaces beyond the capabilities of full
configuration interaction (FCI) and can return the active space 2-RDM. The method is
therefore ideal to replace the FCI solver in the complete active space configuration
interaction (CASCI) and complete active space self consistent field (CASSCF) methods. The
link to the user manual can be found in the section SEE ALSO.
OPTIONS
SYMMETRY
Conventions for the symmetry group and irrep numbers (same as psi4):
| 0 1 2 3 4 5 6 7
---------|-----------------------------------------
0 : c1 | A
1 : ci | Ag Au
2 : c2 | A B
3 : cs | Ap App
4 : d2 | A B1 B2 B3
5 : c2v | A1 A2 B1 B2
6 : c2h | Ag Bg Au Bu
7 : d2h | Ag B1g B2g B3g Au B1u B2u B3u
ARGUMENTS
-f, --fcidump=filename
Set the fcidump filename. Note that orbital irreps in this file follow molpro
convention!
-g, --group=int
Set the psi4 symmetry group number [0-7] which corresponds to the fcidump file.
-m, --multiplicity=int
Overwrite the spin multiplicity [2S+1] of the fcidump file.
-n, --nelectrons=int
Overwrite the number of electrons of the fcidump file.
-i, --irrep=int
Overwrite the target wavefunction irrep [0-7] of the fcidump file (psi4
convention).
-D, --sweep_d=int,int,int
Set the bond dimensions for the successive sweep instructions (positive integers).
-E, --sweep_econv=flt,flt,flt
Set the energy convergence to stop sweep instructions (positive floats).
-M, --sweep_maxit=int,int,int
Set the maximum number of sweeps for the sweep instructions (positive integers).
-N, --sweep_noise=flt,flt,flt
Set the noise prefactors for the successive sweep instructions (floats).
-e, --excitation=int
Set which excitation should be calculated (positive integer). If not set, the
ground state is calculated.
-o, --twodmfile=filename
Set the filename to dump the 2-RDM. If not set, the 2-RDM is not dumped.
-c, --checkpoint
Read and create MPS checkpoints.
-p, --print_corr
Print correlation functions.
-t, --tmpfolder=path
Overwrite the tmp folder for the renormalized operators (default /tmp).
-r, --reorder=int,int,int
Specify an orbital reordering w.r.t. the fcidump file (counting starts at 0).
-h, --help
Display this help.
EXAMPLE
$ cd /tmp
$ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/matrixelements/H2O.631G.FCIDUMP'
$ ls -al H2O.631G.FCIDUMP
$ chemps2 --fcidump=H2O.631G.FCIDUMP \
--group=5 \
--sweep_d=200,1000 \
--sweep_econv=1e-8,1e-8 \
--sweep_maxit=2,10 \
--sweep_noise=0.05,0.0 \
--twodmfile=2dm.out \
--print_corr \
--reorder=6,5,4,3,2,1,0,7,8,9,10,11,12
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