Provided by: chemps2_1.8.8-1_amd64 bug

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-,  3-,  and  4-RDM.  The
       method  is  therefore  ideal  to  replace the FCI solver in the complete active space self
       consistent field (CASSCF) and complete  active  space  second  order  perturbation  theory
       (CASPT2) 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, --file=inputfile
              Specify the input file.

       -v, --version
              Print the version of chemps2.

       -h, --help
              Display this help.

   INPUT FILE
       FCIDUMP = /path/to/fcidump
              Note that orbital irreps in the FCIDUMP file follow molpro convention!

       GROUP = int
              Set the psi4 symmetry group number [0-7] which corresponds to the FCIDUMP file.

       MULTIPLICITY = int
              Overwrite the spin multiplicity [2S+1] of the FCIDUMP file.

       NELECTRONS = int
              Overwrite the number of electrons of the FCIDUMP file.

       IRREP = int
              Overwrite   the   target  wavefunction  irrep  [0-7]  of  the  FCIDUMP  file  (psi4
              convention).

       EXCITATION = int
              Set which excitation should be calculated. If zero, the ground state is  calculated
              (default 0).

       SWEEP_STATES = int,int,int
              Set  the  number  of  reduced  renormalized  basis  states for the successive sweep
              instructions (positive integers).

       SWEEP_ENERGY_CONV = flt,flt,flt
              Set the energy convergence to stop  the  successive  sweep  instructions  (positive
              floats).

       SWEEP_MAX_SWEEPS = int,int,int
              Set  the  maximum  number of sweeps for the successive sweep instructions (positive
              integers).

       SWEEP_NOISE_PREFAC = flt,flt,flt
              Set the noise prefactors for the successive sweep instructions (floats).

       SWEEP_DVDSON_RTOL = flt,flt,flt
              Set the residual norm tolerance for the Davidson algorithm for the successive sweep
              instructions (positive floats).

       NOCC = int,int,int,int
              Set  the  number  of  occupied  (external  core)  orbitals  per  irrep  (psi4 irrep
              ordering).

       NACT = int,int,int,int
              Set the number of active orbitals per irrep (psi4 irrep ordering).

       NVIR = int,int,int,int
              Set the number of virtual (secondary) orbitals per irrep (psi4 irrep ordering).

       MOLCAS_2RDM = /path/to/2rdm/output
              When all orbitals are active orbitals, write out the  2-RDM  in  HDF5  format  when
              specified (default unspecified).

       MOLCAS_3RDM = /path/to/3rdm/output
              When  all  orbitals  are  active  orbitals, write out the 3-RDM in HDF5 format when
              specified (default unspecified).

       MOLCAS_F4RDM = /path/to/f4rdm/output
              When all orbitals are active orbitals, write out the 4-RDM contracted with the Fock
              operator in HDF5 format when specified (default unspecified).

       MOLCAS_FOCK = /path/to/fock/input
              When  all  orbitals  are  active  orbitals,  read  in this file containing the Fock
              operator (default unspecified).

       MOLCAS_FIEDLER = bool
              When all orbitals are active orbitals, switch on orbital reordering  based  on  the
              Fiedler vector of the exchange matrix (TRUE or FALSE; default FALSE).

       MOLCAS_ORDER = int,int,int,int
              When all orbitals are active orbitals, provide a custom orbital reordering (default
              unspecified). When specified, this option takes precedence over MOLCAS_FIEDLER.

       MOLCAS_OCC = int,int,int,int
              When all orbitals are active orbitals, set initial guess  to  an  ROHF  determinant
              (default  unspecified).  The occupancy integers should be 0, 1 or 2 and the orbital
              ordering convention is FCIDUMP.

       MOLCAS_MPS = bool
              When all orbitals are active orbitals, switch on the creation  of  MPS  checkpoints
              (TRUE or FALSE; default FALSE).

       MOLCAS_STATE_AVG = bool
              Switch  on  writing to disk of N-RDMs of intermediate roots (TRUE or FALSE; default
              FALSE).

       SCF_STATE_AVG = bool
              Switch on state-averaging (TRUE or FALSE; default FALSE).

       SCF_DIIS_THR = flt
              Switch on DIIS when the update norm is smaller than the  given  threshold  (default
              0.0).

       SCF_GRAD_THR = flt
              Gradient  norm threshold for convergence of the DMRG-SCF orbital rotations (default
              1e-6).

       SCF_MAX_ITER = int
              Specify the maximum number of DMRG-SCF iterations (default 100).

       SCF_ACTIVE_SPACE = char
              Rotate the active space orbitals: no additional  rotations  (I),  natural  orbitals
              (N), localized and ordered orbitals (L), or ordered orbitals only (F) (default I).

       SCF_MOLDEN = /path/to/molden
              Rotate  the  FCIDUMP orbitals to the DMRG-SCF occupied (external core), active, and
              virtual (secondary) orbitals.

       CASPT2_CALC = bool
              Switch on the CASPT2 calculation (TRUE or FALSE; default FALSE).

       CASPT2_ORBS = char
              Perform the DMRG calculation for the 4-RDM in the SCF_ACTIVE_SPACE orbitals (A)  or
              in the pseudocanonical orbitals (P) (default A).

       CASPT2_IPEA = flt
              Ionization potential - electron affinity shift (default 0.0).

       CASPT2_IMAG = flt
              Imaginary level shift (default 0.0).

       CASPT2_CHECKPT = bool
              Create  checkpoints  to  continue  the  CASPT2 4-RDM calculation over multiple runs
              (TRUE or FALSE; default FALSE).

       CASPT2_CUMUL = bool
              Use a cumulant approximation for the CASPT2 4-RDM and overwrite  CASPT2_CHECKPT  to
              FALSE (TRUE or FALSE; default FALSE).

       PRINT_CORR = bool
              Print correlation functions (TRUE or FALSE; default FALSE).

       TMP_FOLDER = /path/to/tmp/folder
              Overwrite the tmp folder for the renormalized operators. With MPI, separate folders
              per process can (but do not have to) be used (default /tmp).

   EXAMPLE
        $ cd /tmp
        $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/matrixelements/N2.CCPVDZ.FCIDUMP'
        $ ls -al N2.CCPVDZ.FCIDUMP
        $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/test14.input'
        $ sed -i "s/path\/to/tmp/" test14.input
        $ cat test14.input
        $ chemps2 --file=test14.input

AUTHOR

       Written by Sebastian Wouters <sebastianwouters@gmail.com>

BUGS

       Reporting bugs: https://github.com/sebwouters/CheMPS2/issues

SEE ALSO

       User manual: http://sebwouters.github.io/CheMPS2/index.html

COPYRIGHT

       CheMPS2: a spin-adapted implementation of DMRG for ab initio quantum chemistry
       Copyright (C) 2013-2018 Sebastian Wouters

       This program is free software; you can redistribute it and/or modify
       it under the terms of the GNU General Public License as published by
       the Free Software Foundation; either version 2 of the License, or
       (at your option) any later version.

       This program is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
       GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with this program; if not, write to the Free Software Foundation, Inc.,
       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.