Questions tagged [fortran]

For questions related to interpreting/debugging FORTRAN modeling code. Note, this tag need not be used for every question about FORTRAN software (like MOLPRO). It is only need for questions directly concerned with the code of such programs.

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Abaqus UMAT [Fortran]: how to call a function from another function without getting "unresolved external symbol"

I am currently working on implementing a material model in an Abaqus UMAT. The code is structured like this ...
Noco's user avatar
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5 votes
1 answer
148 views

Contents of a CHGCAR file and how to read it appropriately in Python? [duplicate]

Rephrasing the above, what is the content of the data in the CHGCAR file? Is the data part shown below representative of the electron-charge density or is it the actual charge in the system and I have ...
Pranoy Ray's user avatar
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4 votes
1 answer
115 views

Inverse Matrix Calculation

I am working on the charge transport calculation, based on the non-equilibrium green function method, for the Hamiltonian with the non-orthogonal basis. Suppose $H$ and $S$ are the Kohn-Sham ...
Kieran's user avatar
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5 votes
1 answer
277 views

Reading DCD files using Python without using third party packages?

I am trying to read a Nanoscale Molecular Dynamics (NAMD), Dihedral Coordinates (DCD) file using Python. Following the code given at here to read DCD files using Fortran, I have written the following ...
Hemanth Haridas's user avatar
3 votes
2 answers
253 views

Is this "internal error" reproducible when compiling OpenMolcas on other Intel compilers?

The procedure I've been following to build OpenMolcas with an Intel Fortran compiler in the Compute Canada environment is as follows: ...
Nike Dattani's user avatar
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3 votes
2 answers
249 views

How to use the GDB debugger with OpenMolcas?

I would like to follow how some variables are changing during an OpenMolcas calculation, and adding WRITE statements has become too tedious. I've compiled with the <...
Nike Dattani's user avatar
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13 votes
3 answers
229 views

Improving my programming for computational chemistry/physics

What are some good textbooks or online resources to improve my skills in C++, C and Fortran, specifically for computational chemistry. For example, I am interested in learning about parallelisation ...
Fracton's user avatar
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2 votes
0 answers
57 views

how to incorporate size polydispersity in colloidal suspensions [closed]

Basically, I'm working on spherical colloids and investigating the phase behavior of these monodisperse colloids using Monte Carlo simulations (Fortran 77 coding). Now I want to introduce size ...
siva ram's user avatar
1 vote
1 answer
99 views

Why does naming a variable "NU" instead of e.g. "ANU" change the output of my UMAT? (Abaqus/Fortran)

I am starting to learn how to write UMATs in Abaqus, so I took the most simple example, which is linear elasticity (Hooke's law), and implemented it. I tested it on a 3D-rectangular body with a fixed ...
Noco's user avatar
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5 votes
1 answer
414 views

Programming auto-correlation function calculation

I have a set of data (heat flow) values in x, y and z directions for which I have to calculate the auto-correlation function to get the thermal conductivity. I have written a small Fortran90 code but ...
Pascal's user avatar
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7 votes
1 answer
711 views

How to read QE's wfc*.dat files with python

I'm working with QE 7.0 for the computation of some properties of solids. My working theory requires me to access all the information inside the wfc#c.dat/h5 files, created in the prefix.save ...
Amir K's user avatar
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5 votes
1 answer
93 views

About the order of indices in basis set expansion

In many books, e.g., Szabo and Ostlund, Helgaker Jorgensen and Olsen, etc etc, the expansion of Hartree-Fock orbital by basis set is written as a kind of $$ \phi_i = \sum_{\mu} C_{\mu i} \chi_{\mu} $$ ...
Lancashire3000's user avatar
7 votes
1 answer
343 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 ...
user avatar
9 votes
0 answers
207 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 ...
Lancashire3000's user avatar
21 votes
9 answers
9k views

How to master Fortran with minimal effort?

Fortran language is used in many first-principles matter modeling codes, such as VASP and QE. These codes usually include many ...
Jack's user avatar
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9 votes
2 answers
1k views

What is the format of the electron-density data in a CHGCAR file?

Rephrasing the above, what is the pattern in which the electron-density data is stored in the CHGCAR file? I understand that the electron density data in a CHGCAR file is in the form of a 3D Fortran ...
Pranoy Ray's user avatar
  • 1,611