1CHEMPS2(1) chemps2 v1.8.9 CHEMPS2(1)
2
6 chemps2 - spin-adapted DMRG for ab initio quantum chemistry
7
10 chemps2 [OPTION] ...
11
14 chemps2 is a scientific code to perform spin-adapted density matrix
15 renormalization group (DMRG) calculations for ab initio quantum chem‐
16 istry fcidump files. This method allows one to obtain numerical accu‐
17 racy in active spaces beyond the capabilities of full configuration
18 interaction (FCI) and can return the active space 2-, 3-, and 4-RDM.
19 The method is therefore ideal to replace the FCI solver in the complete
20 active space self consistent field (CASSCF) and complete active space
21 second order perturbation theory (CASPT2) methods. The link to the user
22 manual can be found in the section SEE ALSO.
23
26 SYMMETRY
27 Conventions for the symmetry group and irrep numbers (same as psi4):
28 | 0 1 2 3 4 5 6 7
30 ---------|-----------------------------------------
31 0 : c1 | A
32 1 : ci | Ag Au
33 2 : c2 | A B
34 3 : cs | Ap App
35 4 : d2 | A B1 B2 B3
36 5 : c2v | A1 A2 B1 B2
37 6 : c2h | Ag Bg Au Bu
38 7 : d2h | Ag B1g B2g B3g Au B1u B2u B3u
39 ARGUMENTS
41 -f, --file=inputfile
42 Specify the input file.
43 -v, --version
45 Print the version of chemps2.
46 -h, --help
48 Display this help.
49 INPUT FILE
51 FCIDUMP = /path/to/fcidump
52 Note that orbital irreps in the FCIDUMP file follow molpro con‐
53 vention!
54 GROUP = int
56 Set the psi4 symmetry group number [0-7] which corresponds to
57 the FCIDUMP file.
58 MULTIPLICITY = int
60 Overwrite the spin multiplicity [2S+1] of the FCIDUMP file.
61 NELECTRONS = int
63 Overwrite the number of electrons of the FCIDUMP file.
64 IRREP = int
66 Overwrite the target wavefunction irrep [0-7] of the FCIDUMP
67 file (psi4 convention).
68 EXCITATION = int
70 Set which excitation should be calculated. If zero, the ground
71 state is calculated (default 0).
72 SWEEP_STATES = int,int,int
74 Set the number of reduced renormalized basis states for the suc‐
75 cessive sweep instructions (positive integers).
76 SWEEP_ENERGY_CONV = flt,flt,flt
78 Set the energy convergence to stop the successive sweep instruc‐
79 tions (positive floats).
80 SWEEP_MAX_SWEEPS = int,int,int
82 Set the maximum number of sweeps for the successive sweep
83 instructions (positive integers).
84 SWEEP_NOISE_PREFAC = flt,flt,flt
86 Set the noise prefactors for the successive sweep instructions
87 (floats).
88 SWEEP_DVDSON_RTOL = flt,flt,flt
90 Set the residual norm tolerance for the Davidson algorithm for
91 the successive sweep instructions (positive floats).
92 NOCC = int,int,int,int
94 Set the number of occupied (external core) orbitals per irrep
95 (psi4 irrep ordering).
96 NACT = int,int,int,int
98 Set the number of active orbitals per irrep (psi4 irrep order‐
99 ing).
100 NVIR = int,int,int,int
102 Set the number of virtual (secondary) orbitals per irrep (psi4
103 irrep ordering).
104 MOLCAS_2RDM = /path/to/2rdm/output
106 When all orbitals are active orbitals, write out the 2-RDM in
107 HDF5 format when specified (default unspecified).
108 MOLCAS_3RDM = /path/to/3rdm/output
110 When all orbitals are active orbitals, write out the 3-RDM in
111 HDF5 format when specified (default unspecified).
112 MOLCAS_F4RDM = /path/to/f4rdm/output
114 When all orbitals are active orbitals, write out the 4-RDM con‐
115 tracted with the Fock operator in HDF5 format when specified
116 (default unspecified).
117 MOLCAS_FOCK = /path/to/fock/input
119 When all orbitals are active orbitals, read in this file con‐
120 taining the Fock operator (default unspecified).
121 MOLCAS_FIEDLER = bool
123 When all orbitals are active orbitals, switch on orbital
124 reordering based on the Fiedler vector of the exchange matrix
125 (TRUE or FALSE; default FALSE).
126 MOLCAS_ORDER = int,int,int,int
128 When all orbitals are active orbitals, provide a custom orbital
129 reordering (default unspecified). When specified, this option
130 takes precedence over MOLCAS_FIEDLER.
131 MOLCAS_OCC = int,int,int,int
133 When all orbitals are active orbitals, set initial guess to an
134 ROHF determinant (default unspecified). The occupancy integers
135 should be 0, 1 or 2 and the orbital ordering convention is
136 FCIDUMP.
137 MOLCAS_MPS = bool
139 When all orbitals are active orbitals, switch on the creation of
140 MPS checkpoints (TRUE or FALSE; default FALSE).
141 MOLCAS_STATE_AVG = bool
143 Switch on writing to disk of N-RDMs of intermediate roots (TRUE
144 or FALSE; default FALSE).
145 SCF_STATE_AVG = bool
147 Switch on state-averaging (TRUE or FALSE; default FALSE).
148 SCF_DIIS_THR = flt
150 Switch on DIIS when the update norm is smaller than the given
151 threshold (default 0.0).
152 SCF_GRAD_THR = flt
154 Gradient norm threshold for convergence of the DMRG-SCF orbital
155 rotations (default 1e-6).
156 SCF_MAX_ITER = int
158 Specify the maximum number of DMRG-SCF iterations (default 100).
159 SCF_ACTIVE_SPACE = char
161 Rotate the active space orbitals: no additional rotations (I),
162 natural orbitals (N), localized and ordered orbitals (L), or
163 ordered orbitals only (F) (default I).
164 SCF_MOLDEN = /path/to/molden
166 Rotate the FCIDUMP orbitals to the DMRG-SCF occupied (external
167 core), active, and virtual (secondary) orbitals.
168 CASPT2_CALC = bool
170 Switch on the CASPT2 calculation (TRUE or FALSE; default FALSE).
171 CASPT2_ORBS = char
173 Perform the DMRG calculation for the 4-RDM in the
174 SCF_ACTIVE_SPACE orbitals (A) or in the pseudocanonical orbitals
175 (P) (default A).
176 CASPT2_IPEA = flt
178 Ionization potential - electron affinity shift (default 0.0).
179 CASPT2_IMAG = flt
181 Imaginary level shift (default 0.0).
182 CASPT2_CHECKPT = bool
184 Create checkpoints to continue the CASPT2 4-RDM calculation over
185 multiple runs (TRUE or FALSE; default FALSE).
186 CASPT2_CUMUL = bool
188 Use a cumulant approximation for the CASPT2 4-RDM and overwrite
189 CASPT2_CHECKPT to FALSE (TRUE or FALSE; default FALSE).
190 PRINT_CORR = bool
192 Print correlation functions (TRUE or FALSE; default FALSE).
193 TMP_FOLDER = /path/to/tmp/folder
195 Overwrite the tmp folder for the renormalized operators. With
196 MPI, separate folders per process can (but do not have to) be
197 used (default /tmp).
198 EXAMPLE
200 $ cd /tmp
201 $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/matrixelements/N2.CCPVDZ.FCIDUMP'
202 $ ls -al N2.CCPVDZ.FCIDUMP
203 $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/test14.input'
204 $ sed -i "s/path\/to/tmp/" test14.input
205 $ cat test14.input
206 $ chemps2 --file=test14.input
207
210 Written by Sebastian Wouters <sebastianwouters@gmail.com>
211
214 Reporting bugs: https://github.com/sebwouters/CheMPS2/issues
215
218 User manual: http://sebwouters.github.io/CheMPS2/index.html
219
222 CheMPS2: a spin-adapted implementation of DMRG for ab initio quantum chemistry
223 Copyright (C) 2013-2018 Sebastian Wouters
224 This program is free software; you can redistribute it and/or modify
226 it under the terms of the GNU General Public License as published by
227 the Free Software Foundation; either version 2 of the License, or
228 (at your option) any later version.
229 This program is distributed in the hope that it will be useful,
231 but WITHOUT ANY WARRANTY; without even the implied warranty of
232 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
233 GNU General Public License for more details.
234 You should have received a copy of the GNU General Public License along
236 with this program; if not, write to the Free Software Foundation, Inc.,
237 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
238version 1.8.9 29 October 2018 CHEMPS2(1)