85 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 ...
Nike Dattani - No Free Time's user avatar
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. ...
Nike Dattani - No Free Time's user avatar
40 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,...
pmu2022's user avatar
  • 618
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 ...
Cody Aldaz's user avatar
  • 8,017
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 ...
Michael F. Herbst's user avatar
35 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 ...
J.G.'s user avatar
  • 451
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 ...
Antoine Levitt's user avatar
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 ...
TheSimpliFire's user avatar
31 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....
Fabian's user avatar
  • 1,421
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 ...
Ivan's user avatar
  • 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: ...
schneiderfelipe's user avatar
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: ...
Phil Hasnip's user avatar
  • 7,262
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 -> ...
Geoff Hutchison's user avatar
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 ...
Jack's user avatar
  • 15.1k
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 ...
taciteloquence's user avatar
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 ...
Greg's user avatar
  • 1,807
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 ...
B. Kelly's user avatar
  • 4,366
24 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 ...
Tyberius's user avatar
  • 15.5k
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 ...
Nike Dattani - No Free Time's user avatar
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, ...
Andrew Rosen's user avatar
  • 7,361
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 ...
Tyberius's user avatar
  • 15.5k
23 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 ...
Michael F. Herbst's user avatar
23 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 ...
Kevin J. May's user avatar
  • 3,161
22 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 ...
Mythreyi's user avatar
  • 1,359
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 ...
Alessio Valentini's user avatar
21 votes
Accepted

Is there a set of updated, comprehensive benchmarks for speed comparison between different quantum chemistry packages?

The problem is that this is a highly volatile question. In order to meaningfully benchmark programs, you have to use the exact same compiler flags (may require heavy hacking) and use the same ...
Susi Lehtola's user avatar
  • 19.1k
20 votes
Accepted

How to calculate diffraction pattern from a model of unit cell?

Perhaps the easiest solution is to use VESTA, which can read in a CIF (and many other crystalline structure formats) and produce a powder diffraction pattern ("Utilities" > "Powder Diffraction Pattern"...
Andrew Rosen's user avatar
  • 7,361
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 ...
Fuzzy's user avatar
  • 928
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 ...
DetlevCM's user avatar
  • 621
20 votes

What are the freely available crystal-structure visualization softwares?

OlexSys Olex2 For some applications there exists a elegant software called Olex2 which matches most of the crystallographic requirements of dealing with large systems like metal–organic frameworks.
SalvaCardona's user avatar
  • 1,590

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