Questions tagged [fcidump]
For questions about the FCIDUMP file format used for saving one and two electron integral.
20 questions
4 votes
0 answers
64 views
Nuclear repulsion and core contributions in MRCC fort.55 integrals file
Background I am using MRCC to generate the integrals file (fort.55) for an RHF system (Ne atom in this case) using the frozen core approximation with core=frozen as ...
- 4,076
8 votes
1 answer
432 views
Why does our PySCF-MRCC interface work for B++ but not for Li?
Background My colleague and I have built an interface between PySCF and MRCC which seems to work all the time for RHF references, but only sometimes for UHF references. We use PySCF to calculate the ...
- 4,076
2 votes
0 answers
90 views
Which programs can read an FCIDUMP file for a UHF wavefunction?
Around 4 years ago, a question was asked about which programs can interact with an FCIDUMP file: How do the various programs read or write integrals in FCIDUMP format? In the design of Knowles and ...
- 71
5 votes
2 answers
571 views
FCIDUMP file from UHF calculation in PySCF
Background In PySCF, one can use from_chkfile() to Read SCF results from PySCF chkfile and transform 1e, 2e integrals using the SCF orbitals. The transformed integrals are then written to FCIDUMP file....
- 4,076
7 votes
1 answer
252 views
Using the same input (MINP) file, why does MRCC fail with a "normal" fort.55 file, but succeeds with a longer fort.55 file that has duplicate entries?
I have the following fort.55 file: ...
- 4,076
5 votes
0 answers
126 views
Can PySCF generate FCIDUMPs in native MOLPRO format? [closed]
I am working on a C++ project that entails reading FCIDUMP files and feeding it into some post-HF calculation. For practical reasons, it is more preferable to stick with the native FCIDUMP format of ...
- 91
2 votes
1 answer
742 views
PySCF: How to do CCSD calculations from an FCIDUMP file in HDF5 format?
Recently my question: Why does CCSD work, but not CCSD(T), after reading an FCIDUMP in PySCF? lead to a bug fix that allows users to do CCSD(T) calculations from an FCIDUMP file in PySCF. That was ...
- 38.6k
2 votes
0 answers
151 views
2 votes
1 answer
415 views
Why does CCSD work, but not CCSD(T), after reading an FCIDUMP in PySCF?
CCSD(T) works after an RHF calculation: Input: ...
- 38.6k
2 votes
0 answers
763 views
How to read two electron integrals from pyscf [closed]
This is a follow-up question to this one I asked a few days ago. I in the meantime talked to my teacher and generate all the necessary integrals in PySCF. For the one electron integrals that isn't an ...
- 125
7 votes
1 answer
601 views
Exploiting 8-fold symmetry of ERI tensor for building Coulomb and Exchange matrices
I'm trying to write a restricted Hartree Fock code in Fortran that reads in a file of zeroth-iteration 1 and 2 electron integrals (FCIDUMP format) and uses them to do the SCF procedure from an initial ...
user4763
6 votes
1 answer
1k views
How to compute the overlap matrix in Python
I want to calculate the overlap integral (S), I made the code, but it is only worked when I use a basis function that describe 1s and when I include 2s orbital, I start to get error. The First Problem ...
- 1,899
9 votes
0 answers
399 views
Interacting with pyscf integral library from Fortran [closed]
I would like to use libcint, the integral library in pyscf from Fortran. Its webpage has a Fortran API and developer manual, but ...
- 182
8 votes
1 answer
204 views
How to read data from an input and form two-electrons integral?
I am doing a code that can calculate the hartree-fock energy. I want to form the two-electrons integral by reading the data from the input like this one below. The first four number are the indices ...
- 1,899
8 votes
1 answer
315 views
What do the parameters at the top of an FCIDUMP file mean?
A while ago I wrote a simple program that takes in an FCIDUMP file (generated by MOLRPO) and can determine matrix elements (or ...
- 740