Questions tagged [software]

Questions about libraries and standalone software designed or well-suited for scientific or numerical calculations.

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maxwell and kelvin models via prony series in abaqus

abaqus documentation only shows generalized models and their formulae. What are the prony series in abaqus for the simplest maxwell and kelvin models?
feynman's user avatar
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1 answer
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Rolling friction settings in COMMERCIAL (Ansys) finite element software

Is there a standard way of implementing rolling friction in COMMERCIAL finite element software? There's no book about such a subject in COMMERCIAL FEM software though there are books on algorithms ...
feynman's user avatar
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Most promising reduced order modeling method

Many players in the field of engineering simulation software are investing on digital twinning and reduced order modeling techniques, meaning that the field bears potential. I was wondering if among ...
Lilla's user avatar
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3 votes
1 answer
155 views

How to convert number systems on Sharp calculator if the number has decimal points, for example 3B.254?

I would like convert decimal octal numbers on sharp EL-531TH (or any other) caclulator but when I enable the octal or any other non-decimal function, the decimal key or dot key (marked with red) is ...
Alezigl's user avatar
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Why researchers use MATLAB based YALMIP or CasADi for MPC?

I was looking at various research papers and most of the researchers use CasADi, YALMIP, MPCTools to implement MPC. My question is "Why researchers use MATLAB based YALMIP or CasADi for MPC ...
Khalid Umer's user avatar
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1 answer
135 views

AMR-Capable meshing software that is not based on quad/octrees

I am looking for AMR/re-meshing software (structured grids would suffice) that is NOT based on quad-octrees, i.e., a fixed refinement rate of 2 but (ideally) something user defined, i.e., ratios of 1....
Dan Doe's user avatar
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1 vote
2 answers
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Can I find sines or cosines of rational parts of π without using radians? If not, how do I reduce the errors caused solely by the transcendence of π?

this may be irrelevant for people who need fast code. But for me it's just the opposite -- i.e. in the specific situations when I know that the extra time allows me to make my calculations more ...
5-limit_JI's user avatar
1 vote
1 answer
198 views

Research profile vs coding expertise for scientific programming career

This is a question to all scientific programmers out there that have experience in academia, industry, ideally both. Consider two figures: Alice has earned a PhD in applied mathematics at a top 10 ...
Lilla's user avatar
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1 answer
119 views

Issues with Simulating the Orbits of Mars and Earth using MATLAB and Runge-Kutta Method

I'm trying to simulate the orbits of Mars and Earth in MATLAB using the 4th order Runge-Kutta method for numerical integration. However, the orbits appear as straight lines rather than the expected ...
Javadkhan's user avatar
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1 answer
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1 dimensional simulation of gravity fails

In 1D the force of gravity does not diminish with distance however here I use 1D to mean the point mass only moves in a line in 3D space, with the other mass stationary at the origin. I started by ...
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2 votes
1 answer
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Best approach to simulating dynamics on networks

I have been recently getting into the field of various processes on networks. For example, stochastic processes like percolation, Ising models, various statistical-physics models; or deterministic ...
YeatTheorem's user avatar
3 votes
1 answer
418 views

Good IDE for GNU Octave?

Are there any good IDEs for working with Octave code? I'm used to type hints and documentation preview from software like IntelliJ or VS Code. While there are syntax highlighting plugins for VSC, all ...
Vincent Guttmann's user avatar
1 vote
1 answer
205 views

Issue in implementing a cloth simulation using verlet integration

I am trying to implement a cloth simulation in c++ using verlet integration and I'm getting some odd issues that I can't seem to explain, the points in the cloth seem to fly around and have weird ...
סתיו פארן's user avatar
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Geant4, simulate photon emitted into lead

I have just learned Geant4 and recently I tried to simulate photons emitted into lead. After I collected the data and figured out the transmission of photons. I found my data is bigger than the ...
SHZ's user avatar
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7 votes
4 answers
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Euler integration of the three-body problem

Me and one of my colleague are trying to simulate the three-body problem with a C++ program in order to compare different integration schemes. At the moment we are trying to use the Euler's method, ...
jack23456's user avatar
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Implementations of the Eisenstat-trick for SSOR

Where can I find a source code for the SSOR method with Eisenstat's trick? The original paper includes pseudo code but also seems to have minor typos. For that reason, I would be very happy to see an ...
shuhalo's user avatar
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2 votes
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Software for Smith form or Hermite form of a sparse polynomial matrix

In a current research project, I have a number of matrices with coefficients in ℚ[𝑥] for which I want to understand how their rank depends on the value of the parameter 𝑥. These matrices are: ...
Vladimir Dotsenko's user avatar
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I need MATLAB or Mathematica code to solve this integral over limit 0- λ

I want the code to integrate equation(1) or (2) over the limits using mathematical or mathlab to get equation (3) as the answer of $Z$ vibrational partition function, giving the following additional ...
tolulope ojuola's user avatar
5 votes
1 answer
92 views

Software for Feasibility Problems

I face a feasibility problem of type $$ c_i(\boldsymbol x) \leq 0, i = 1, \dots, \mathcal{I} \\ c_e(\boldsymbol x) = 0, e = 1, \dots, \mathcal{E} $$ where $\mathcal{I} + \mathcal{E} \gg \text{dim}(\...
Dan Doe's user avatar
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Book recommendation request: A good C++ based software development book for a computational mathematician

I'm hoping that this type of question is on-topic, and I have put in a little hunting to make sure it isn't a flat out repeat. If it is either of the above, I apologize in advance. I'm an early career ...
Chessnerd321's user avatar
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How can I couple MCNP with FLUKA? To attain reactor dynamics and simulate an ADS experiment? (Under Subcritical fast system)

I'm new in Particle Physics based Computing. I want to simulate an ADS experiment (Accelerator Driven System) in subcritical fast system. I was advised to simulate the experiment with FLUKA with MCNP ...
Ammar's user avatar
  • 11
0 votes
3 answers
89 views

How can I plot a rainbow?

I'm trying to write a program that can simulate a rainbow. So far I've got figured out how to determine the change in the refractive index depending on the wavelength, the angular deviation of the ...
Jeff's user avatar
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1 answer
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Convoluted exponential gaussian probability function from Igor Pro

I am trying to figure out the exact formula for a three convoluted exponential gaussian probability function from the software Igor Pro, from my research. Unfortunately all I the closest equation from ...
lPhysics's user avatar
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How to solve nonlinear second order ODE in Matlab? [duplicate]

I am working on simulating a car suspension system using Matlab. Specifically, I have to derive equation of motion using the Lagrange method and then use ode 45 to solve it. However, while using ...
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Continuum solutions for the Dirac equation in Coulomb potential - numerical codes

Following the representation used in [1, pag. 11] the solution of the Dirac equation in polar coordinates for energy $E$ is of the type: $$ \psi_{E\kappa m}(\bf{r})= \dfrac{1}{r} \Bigg( \begin{matrix} ...
081N's user avatar
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2 votes
1 answer
633 views

Reference request: C++ and numerical analysis book

I'm a master student with a good Numerical analysis background. I'm going to do a master thesis in the same subject, but I need to use C++ since my advisor loves it, and I also believe it's the best ...
FEGirl's user avatar
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2 votes
2 answers
1k views

Diagonalization using LAPACK

Say, we have a Hamiltonian which for simplicity does not mix particle hole sectors. It is just a simple Hamiltonian in real space as shown, $H=\sum_{ij,\sigma} A(i,j)(c_{i\sigma}^{\dagger}c_{j\sigma} +...
Annie's user avatar
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1 vote
2 answers
292 views

Numerical minimization of the action in python

I want to find the trajectory $x(t)$ which minimizes the action $S = \int_{t_i}^{t_f} L(x(t), \dot{x}(t)) \mathrm{d}t$ numerically. I am trying to do it by discretizing the action so it is more of a ...
user avatar
0 votes
3 answers
5k views

Draw magnetic field lines or vector field of a magnetic dipole - Python/Matplotlib

In the Wikipedia article on magnetic moments, subsection "Effects on environment" defines the magnetic field H of a magnetic dipole moment. Additionally the magnetic field lines of this ...
tester931's user avatar
1 vote
0 answers
1k views

Open-source Hexahedral meshing tools

I'm looking for an open-source automatic meshing tool or library able to generate full or dominant hexahedral mesh starting from a provided arbitrary model i.e. a surface triangular mesh stored in STL ...
Ricla's user avatar
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-1 votes
1 answer
46 views

Trouble Estimating Motor Parameters with Least Squares in MATLAB

Basically, I'm trying to use Least-Squares to estimate the parameters of a DC motor. My system can be modeled by the following matrix equation: $$\begin{bmatrix}V_{input}(t)\\0\end{bmatrix}=\begin{...
CoilKid's user avatar
  • 109
1 vote
1 answer
476 views

Solution of Coupled Differential equation for a 2d linear flow using RK4 method in python 3

I want to study the dynamics of a 2d linear flow, whose dynamical equation is- $\begin{pmatrix} \dot{x_1}\\ \dot{x_2}\\ \end{pmatrix}=\begin{pmatrix} 1 & 1\\ 4 & -2\\ \end{pmatrix}\begin{...
Anirban Majumdar's user avatar
13 votes
3 answers
35k views

How to properly calculate CPU and GPU FLOPS performance?

Problem I'm trying to calculate CPU / GPU FLOPS performance but I'm not sure if I'm doing it correctly. Let's say we have: A Kaby Lake CPU (clock: 2.8 GHz, cores: 4, threads: 8) A Pascal GPU (clock: ...
AlekseyHoffman's user avatar
1 vote
0 answers
103 views

I'm trying to add a colour to the LogicalVolume in Geant4. I get the error that fVisAttributes and visAttributes are undefined. How can I fix this?

I'm trying to add a colour to the LogicalVolume which has been renamed to TrackerLogical in Geant4. I get the error that fVisAttributes and visAttributes are undefined although I have defined them in ...
A.Sa's user avatar
  • 11
6 votes
3 answers
168 views

Coroutines for ODE solvers

Are there any ODE solver packages that use coroutines and yield their results instead of functions and returning? Briefly, a subroutine in a programming language does some computations, returns a ...
Daniel Shapero's user avatar
2 votes
2 answers
333 views

Writing code on the CPU while developing, running it on the GPU when live - which approach?

In my simulations I am using dense matrix-vector multiplications and 2D-fft transformations quite often, for matrix sizes of 8kx8k and up. Hence, I assume that using a GPU is beneficial for speeding ...
arc_lupus's user avatar
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0 votes
0 answers
57 views

Is it possble to do this complex symbolic calculation with Matlab?

Sorry it's bit abrupt, but recently I am caught up in some symbolic calcualtion which is tedious and almost impossible with mere human hands, so just wondering is it possible to solve the double ...
Tim Peng's user avatar
15 votes
3 answers
762 views

What guidelines should I follow for simulation software projects?

I am not sure whether this question belongs here, but I would like to give it a try and benefit from the experience of the people at scicomp.SE. From my experience, the software quality in ...
carlosvalderrama's user avatar
1 vote
1 answer
132 views

Manual for library Libxc

Where can I find the manual for software library Libxc for exchange-correlation functionals? Links with domain www.tddft.org don't work.
tohoyn's user avatar
  • 331
11 votes
1 answer
460 views

How should errors be reported in scientific libraries?

There are many philosophies in different software engineering disciplines about how libraries should cope with errors or other exceptional conditions. A few of the ones I've seen: Return an error ...
Daniel Shapero's user avatar
1 vote
1 answer
102 views

Best way of storing numerical data in a compact manner, while leaving it accessible for tools like GnuPlot?

My simulation, written in C++, generates a large amount (roughly ~500) of text files for each set of parameters I try to simulate, with four columns of ~5k double values in each file. Furthermore, to ...
arc_lupus's user avatar
  • 553
1 vote
1 answer
250 views

Software for parallel incomplete LU factorisation

I am looking for a software package to compute incomplete LU factorisations in parallel. Further considerations are: The package must allow for arbitrary level-of-fill or threshold-based truncation. ...
gTcV's user avatar
  • 445
1 vote
3 answers
96 views

Software for cellular automota

I would like to do simulations using cellular automata to describe the behavior of influenza. What software do you recommend?
Julio Trujillo Gonzalez's user avatar
4 votes
3 answers
1k views

Best software to do big number calculations quickly

I am trying to do some work on some math conjecture. I am testing the conjecture numbers using very large math numbers (100+ digits ). I am currently using python to test these numbers. In the ...
Rahul Shah's user avatar
5 votes
1 answer
352 views

Integrating/Implementing NURBS-related calculations

Recently, I started to develop some codes that use NURBS (general things I intend to use/already using: spline generation, interpolation, grids, isolines, closest-point find, and many others), both ...
Anton Menshov's user avatar
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0 votes
1 answer
115 views

Which free library should I use to perform cutting/clipping operation?

I have a set of points which forms a closed loop, and I want to perform cutting/clipping a 3D model using this loop. I have used VTK but in some cases, it has a "Cannot follow edges" problem. Is ...
minpu's user avatar
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1 vote
0 answers
77 views

Magnetostatic modelling Radia: Increasing distance between magnets a produces positive force until a certain point, beyond which force goes haywire

I have two sets of magnets. One set consists of two electromagnets (Shown below: Blue) and the other set consists of two NdFeB N40 permanent magnets. Both sets of magnets lie on the same plane. I want ...
James O'Farrell's user avatar
0 votes
1 answer
125 views

Help understanding this numerical surface integration technique?

I'm attempting to write a FORTRAN program that calculates the magnetic field, B, at any point outside of a bar magnet. I'm going to use a first order euler scheme, where each side of the bar magnet ...
dtfd1998's user avatar
0 votes
1 answer
1k views

Finite volume software packages

There are many software packages for the finite element method, of which the most popular are listed e.g. on Wikipedia. When it comes to the finite volume method, I'm not aware of any similarly ...
Jakub Klinkovský's user avatar
0 votes
1 answer
152 views

Converting acceleration over time to velocity or speed in code

I have acceleration data from a sensor. X Y & Z. I move the senor in the Y axis. Mostly in a straight line. So I ignore x & z. From the sensor documentation 5.2.1 Acceleration output: ax=((...
Steve Coleman's user avatar