Questions tagged [high-performance-computing]

Questions concerning high performance computing (HPC).

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42
votes
14answers
6k views

Supercomputers around the world

For a matter modelling person, the most valuable resource is computing power. For many of us, computing power at hand limits the scale of problems we can solve. There are many national supercomputing ...
28
votes
9answers
4k views

Which Linux distribution is best for Matter Modeling?

In some science fields there are efforts to provide customized distributions, so you can get a productive environment with minimum set-up overhead. For example, in high energy particle physics, we ...
12
votes
1answer
407 views

Are there examples of ab initio predictions on small molecules without the "major approximations"?

In most textbooks the precise Schrödinger euqation of a molecule is given (and the "beautiful thing" stops here), then born oppenheimer approximation is made, then layers of other ...
14
votes
5answers
1k views

What are some cloud services for computing?

A group of researchers in my university (including me), started to study the possibility to move to cloud computing services in order to run our simulations. The simulation areas include condensed ...
9
votes
1answer
490 views

Supercomputers around the world, which allow access for researchers outside the country

In a previous question it has been shown the computation capabilities of the countries all over the world. However, if I didn't miss something, the use of such supercomputers is limited to researchers ...
35
votes
13answers
2k views

What is a good programming language for matter modeling?

What is a good programming language for matter (e.g. molecular or materials) modeling? Since this is a broad field, I don't expect there to be only one answer.
9
votes
1answer
400 views

High precision helium energy

In the paper "High Precision Theory of Atomic Helium", Drake lists the then best-known ground state energy of the Schrödinger equation for helium to 22 digits as: $$\lambda_0 \approx -2....
24
votes
6answers
3k views

Are there critical mistakes to avoid when creating a workstation (32-128 cores)?

What are practical concerns for creating a workstation that will likely be expanded in the future to have more workstations/nodes? I am interested in running atomistic and quantum mechanical ...
21
votes
3answers
3k views

Since MKL is not optimized for AMD hardware, should I use a math library specific to AMD, or would an open-source one be just as good?

The codes for quantum mechanical calculations make heavy use of linear algebra, and it seems most of them delegate this task to time-tested and highly optimized libraries, instead of trying to deploy ...
19
votes
3answers
595 views

Materials Modeling with Raspberry Pi?

Does anyone have any knowledge or direction for creating a homemade Beowolf cluster for materials modeling?I would like to be able to run my own "hobby" simulations at home, so a low energy, ...
16
votes
4answers
516 views

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

I've found a page dedicated to quantum chemistry packages benchmarks, on GitHub, qmspeedtest. But most results there are several years old, and so probably outdated. Is there some place where we can ...
13
votes
2answers
332 views

How to get potential energy surface from GAMESS?

I'm trying to learn GAMESS and performing a simple PES scan of oxygen molecule. After the completion of the calculations I get a .log file with lots of sections like that: ...
19
votes
4answers
3k views

Should I buy a CPU or a GPU for doing calculations?

A few years ago there was a significant difference between CPUs and GPUs for performing calculations. It was quite clear when to go for a CPU or a GPU. Today there are GPUs with a very large number ...
11
votes
2answers
735 views

Parallelization in VASP

I have a system that has 1 k-point, 54 atoms, NBANDS=152, and NGZ=80. I'm running an AIMD simulation on VASP version 5.4.4 The ...
14
votes
3answers
5k views

Should I connect 2-3 laptops to form a supercomputer?

I have recently started to use Quantum ESPRESSO for evaluating different properties of ZnSe Quantum Dots. But I currently don't have access to any cluster and as I am increasing the size of ...
23
votes
6answers
5k views

Is ARM64 the next big thing?

Considering how GPUs in matter modeling was first recognized in gaming devices like PlayStation, it is also interesting to consider whether ARM64 chips, which are the type of chips in modern smart ...
15
votes
3answers
2k views

How can I use a GUI on a supercomputer?

I am trying to make plots based to VASP simulation results, but I am struggling with how to download so much data from the server. A lot of examples on the internet are taught using the local desktop ...
8
votes
3answers
187 views

What are the advantages of the Davidson diagonalization method over other sparse matrix diagonalization methods?

I am interested to understand the advantages of the Davidson diagonalization method over other sparse matrix diagonalization routines. For instance, Intel MKL.
10
votes
1answer
308 views

How to understand the wavefunction outputed by QE with HDF5 format?

Following the answer to my question: What is the best program to manipulate numerical DFT wavefunctions to calculate custom matrix elements?, I compiled Quantum ESPRESSO with the hdf5 flag on, and now ...
9
votes
4answers
275 views

What programs can do electron integrals and SCF calculations with more than one CPU?

Similar to this question which asks for each answer to provide one software that can do CASSCF: I am interested in software that can do integrals, SCF (Hartree-Fock), and the integral transformation, ...
17
votes
3answers
1k views

Running Quantum ESPRESSO calculations in Google Colab

So one big problem I experience in doing calculations with Quantum ESPRESSO is that many calculations require a lot of computing power: you need large RAM capacities and powerful processors especially ...
16
votes
3answers
185 views

Job scheduler alternatives

The power of computation required to perform a DFT calculation increases with the size of the system. Therefore, for some systems, is mandatory to use high-performance-computers, clusters, and grids. ...
11
votes
1answer
105 views

Which schedulers are compatible with a virtual machine?

I have an old TORQUE cluster (out of support) with 4 nodes running on Cent OS 6 and I am having trouble using the latest versions of Matter Modelling software. I recently came across Quantum Mobile ...
10
votes
1answer
138 views

What are the trade-offs setting DIRSCF to either .TRUE. or .FALSE. (the default) in GAMESS (US)?

The first software I used to run calculations was Gaussian09. When submitting a input, I used to see a pattern of resource usage where the allocated CPU quickly maxed out, remaining high most of the ...
10
votes
2answers
173 views

Why is Q-Chem producing a parallel efficiency greater than 1?

The efficiency $E$ of a parallel calculation is defined as \begin{align} E &= \frac{S}{N}, & S &= \frac{T_1}{T_N}, \end{align} where $S$ is the speedup and $N$ is the number of workers, ...
9
votes
1answer
423 views

Is it possible to do TD-DFT/6-31G+(d,p) calculations on a laptop?

In the recent publication: "Density Functional Theory Calculation on the Structural, Electronic, and Optical Properties of Fluorene-Based Azo Compounds", the author claimed to have used ...
8
votes
0answers
81 views

What's the largest system we can study based on "fundamental limits to computation"? [closed]

If we have a (classical) computer about the size of a room and if its computational power is only limited by fundamental limits to computation, what is the largest system we can study using different ...
7
votes
1answer
242 views

Running Quantum ESPRESSO on a GPU in Windows

I have been using BURAI GUI for Quantum ESPRESSO for the calculation of optical properties of ZnSe. While running calculations I observed that my laptop's GPU was not even being used and I am a bit ...