82
votes
Accepted
Did the 2019 discovery of O(N log(N)) multiplication have a practical outcome?
What are the state-of-the-art algorithms for long-integer multiplication?
First let me address the point you raised about the schoolbook algorithm having $\mathcal{O}(n^2)$ scaling, by saying that ...
- 33.1k
40
votes
Is there a free package with robust CASSCF functionality?
OpenMOLCAS
I'm surprised that the other two answers were given without yet any mention of OpenMOLCAS yet!
There is a recent paper[1] about it for which I happen to be one of the many co-authors.
...
- 33.1k
39
votes
Accepted
Why do we have so many DFT codes (softwares)? Are they redundant?
There are many reasons why so many different scientific packages have been developed
These packages were developed by individual researchers who were in competition with each other and also work ...
- 7,937
36
votes
Accepted
How is Julia used in matter modeling?
(Disclaimer: As one of the main authors of a Julia-based DFT code, DFTK, my opinion is definitely biased)
The community of people employing Julia for materials modelling is still small, but a couple ...
- 2,364
36
votes
Accepted
How to write my own density functional theory (DFT) code in Python?
Understanding, deriving, writing, testing and debugging an ab initio code can be a lenghty and tedious task. I'd like to provide a starting point for you here. If you just to it for pedagocial reasons,...
- 578
33
votes
What is a good programming language for matter modeling?
Julia
The answers above allude to what some call the "two-language problem". In materials science it takes the form of writing your code in Fortran for speed, and writing an interface to it ...
- 646
33
votes
Did the 2019 discovery of O(N log(N)) multiplication have a practical outcome?
This $O(n\ln n)$ integer multiplication algorithm is a galactic algorithm, meaning that it won't be used despite being "of lower complexity" because it only becomes more efficient than ...
- 431
32
votes
What is a good programming language for matter modeling?
Fortran
A large part of materials modelling involves density functional theory and molecular mechanics. From this compilation of quantum chemistry software, the most widely used programming language ...
- 1,607
30
votes
Accepted
What are the freely available crystal-structure visualization softwares?
ASE
The Atomic Simulation Environment (ASE) has visualization capabilities. It is a python environment that allows direct interaction with a lot of atomistic simulation tools.
https://wiki.fysik.dtu....
- 1,391
30
votes
Which Linux distribution is best for Matter Modeling?
There isn't a silver bullet for this, so in my humble opinion there isn't a "best" Linux distribution for this. Just as Kali is not "the best" for security and Scientific Linux is also not advertised ...
- 879
29
votes
Is there a free package with robust CASSCF functionality?
ORCA
ORCA (forum). It is fully featured, efficient, and free for academics. The input is straightforward:
...
- 1,700
27
votes
Why do we have so many DFT codes (softwares)? Are they redundant?
There are many reasons why we have so many different density functional theory programs, and it would be nigh on impossible to give a full answer encompassing all of them. A brief, select few:
...
- 6,467
25
votes
Enforce a space group on a given crystal structure
While there are undoubtedly other programs that do this, it's fairly easy to do in Avogadro.
I start with a calculation on hexagonal SiC. As mentioned, it starts as $P_1$:
Go to Crystallography -> ...
- 8,655
25
votes
What is a good replacement for Gaussian?
ORCA
Official website: https://orcaforum.kofo.mpg.de/app.php/portal
What is ORCA?
ORCA is a general-purpose quantum chemistry program package that features virtually all modern electronic structure ...
- 14.8k
24
votes
What is a good programming language for matter modeling?
It depends on what you want to do
I'll go first. For context: I do mostly Monte Carlo simulations, especially quantum Monte Carlo. My work has focused on spin systems, using techniques like the ...
- 6,569
24
votes
What is a good programming language for matter modeling?
Python
@taciteloquence has already mentioned Python for data analysis and visualization, but let me add one more angle: automation.
Simulation nowadays often means high-throughput, automated ...
- 1,797
24
votes
What is a good programming language for matter modeling?
Julia
Okay, I have to add Julia.
Everyone is saying Fortran or Python, and I love them both, but they both have issues. Fortran is easy for a compiled language to write, but I still have ...
- 4,306
24
votes
What is a good replacement for Gaussian?
OpenMOLCAS
MOLCAS is now in it's 5th decade! The first version was written in the 1980s by the group of Bjorn Roos, one of history's giants in quantum chemistry. It can do many of the things most ...
- 33.1k
23
votes
Why do we have so many DFT codes (softwares)? Are they redundant?
Another thing not mentioned yet is that there are, broadly speaking, two camps of codes: those that are primarily meant for periodic (often but not exclusively plane-wave) DFT (VASP, Quantum Espresso, ...
- 7,241
23
votes
What are the main computational frameworks used in materials modeling?
Electronic Structure Theory
Much of the behavior we observe from molecules/materials arises from electronic interactions. These interactions are fundamentally quantum mechanical as are most of the ...
- 15k
22
votes
What are the freely available crystal-structure visualization softwares?
pymatgen & ASE
I'm a big fan of simplicity and integration in my python-based and Julia-based workflow.
Therefore I typically directly use the visualisation features from pymatgen, such as ...
- 2,364
22
votes
Did the 2019 discovery of O(N log(N)) multiplication have a practical outcome?
To take a slight detour, we can also look at the progress of matrix multiplication algorithms. As mentioned in a few comments here, standard matrix multiplication is $O(n^{3})$ and any exact method ...
- 15k
22
votes
What software will allow me to combine two images?
Blender
I usually do 3D images with molecules using Blender. You can export your molecule 3D model with a chemistry visualization program (such as vmd or jmol) into Blender (I usually do it using OBJ ...
21
votes
What are the freely available crystal-structure visualization softwares?
OVITO
OVITO is a great tool for visualising supercells and simulation cells with a large number of atoms. There are plenty of modifications available that facilitate analysis, and it also has a Python ...
- 1,339
21
votes
Accepted
Calculating HSE06 band structures on Quantum ESPRESSO
I have seen all the methods you mentioned but have only done one myself; I'll explain here how to use Wannier90 in conjunction with Quantum Espresso to get band structures for hybrid functional ...
- 3,061
20
votes
What is a good programming language for matter modeling?
It depends on what you want to do
It depends on what you want to do. As a couple of others have pointed out, many of the computer programs used in computational chemistry and theoretical solid state ...
- 898
20
votes
What is a good programming language for matter modeling?
It depends on what you want to do
I think one major question that needs to be asked is "What do you want to do?".
Develop new quantum chemistry codes? Use them more efficiently? Automate ...
- 621
20
votes
What software will allow me to combine two images?
VMD can load STL files in text (ASCII) format. Here's how I produced the image below:
Downloaded STL file of teapot from Wikipedia.
This STL file is in binary format, so I used MeshLab to convert it ...
- 1,901
19
votes
What are the main computational frameworks used in materials modeling?
Monte Carlo
In this case there is no one answer, and perhaps no individual best suited to write the full list. I can contribute few words about Monte Carlo methods.
What is Monte Carlo? Monte Carlo (...
- 6,569
19
votes
What is a good programming language for matter modeling?
Python
Python is definitely a good language for scientific calculation.
The syntax is very simple. It is not hard to implement some novel method and conduct preliminary tests.
The library is ...
- 3,751
Only top scored, non community-wiki answers of a minimum length are eligible