Questions tagged [software]

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

Filter by
Sorted by
Tagged with
2
votes
1answer
173 views

Poisson solver diverged

My 2D-Poisson solver is build for simulation of semiconductor. The algorithm is Gauss-Seidel iterative method. If I use simple PN junction for simulation testing, it diverged while I applied high ...
2
votes
1answer
1k views

Celestial mechanics simulation software? The 'N-Body Problem'

What software or sites might simulate an N-body gravitational problem? Application is related to Klemperer Rosette or Iridium Satellites. Bias for C, C++, PHP, or Java. Nice visuals a big plus. ...
2
votes
1answer
2k views

tecplot 360: convert face-centered data to node data

Is there a way in Tecplot to change data from face-centred to node-based? If I look at the plot, it seems to me that internally Tecplot is changing the data from being at the centre of the face to ...
2
votes
1answer
247 views

Dakota Optimizer - plot objective functions in real-time

I am using the Dakota Optimizer. I have 50+ variables, 50+ constraints and more than one objective function. Independent of the actual optimizer used, or the output selected: Is there a way to plot ...
2
votes
1answer
75 views

Integrating from tabular data, in particular steam tables

I'd like to be able to view in graph form the volume and pressure of steam produced from heating water in a sealed vessel, starting from room temperature water. Important variables, such as the ...
2
votes
0answers
49 views

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} ...
2
votes
0answers
275 views

Evaluation of feynman diagrams: FORM vs. Sympy vs. other

I just started working on my master thesis in the theoretical particle physics and my supervisor asked me to start working with FORM, a script interpreter with basic knowledge of lorentz and dirac ...
2
votes
1answer
911 views

How to include parameters in plot title in comsol? [closed]

I have a comsol model. I want to draw a few plots for different values of a global parameter called plot_z, e.g. if plot_z can ...
2
votes
0answers
78 views

Can similarity criterion help reducing calculations in Finite Element Analysis (FEA) problems?

Can similarity criterion help reducing calculations in Finite Element Analysis (FEA) problems? I'm using NX (a thermal and CFD simulation software) to simulate the temperature and fluid field of a ...
2
votes
0answers
169 views

How to print out a network in peersim? [closed]

Peersim is a peer-to-peer network simulator. I'm simply trying to get the program to print out the network (an edge list is fine). Presumably this is possible, since there is an in-built ...
1
vote
2answers
75 views

Help on writing sofware: general guidelines, in particular separation of computation and visualization

Although I already did some work in the intersection of theory and simulation I'm still very new to this field and I need some guidance. If anybody can give some recommendations for introductory ...
1
vote
3answers
1k views

C++ mixed integer nonlinear programming (MINLP) solver

Doing research project in material involving (mixed integer nonlinear programming) MINLP problem, we want to implement MINLP based on C++, because the majority of our project is based on C++. What ...
1
vote
2answers
134 views

convex optimization with objective function given by oracles

Is there any solver for convex optimization in C++ (or some dedicated scheme while no solver is yet available) that could solve a convex optimization problem with objective function value given by an ...
1
vote
1answer
1k views

Solving a problem using multiple threads using CLP

Is it possible to run Clp on multiple threads using Julia and JuMP?
1
vote
2answers
97 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 ...
1
vote
1answer
110 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{...
1
vote
1answer
323 views

Any FOSS MATLAB/Octave toolbox for high-speed variable precision arithmetic?

I need to use variable precision arithmetic in MATLAB for an expensive set of computation. The vpa function provided by the symbolic math toolbox is very slow. I found a non-free alternative toolbox ...
1
vote
2answers
62 views

Automatic motion recognition

How difficult is it to program an automatic software using C that is able to read astronomy images of up to 4096x4096 pixels (or other sensor geometries), search ...
1
vote
1answer
80 views

What are some tips on developing a problem-specific ODE solver?

I have a small system of stiff ODEs describing a chemical reaction. The right-hand side is quite complicated, as well as the Jacobian. This equation will be solved many times with different initial ...
1
vote
1answer
1k views

Multidimensional Minimization: GNU GSL C++ error code 27 for - iteration is not making progress towards solution

I am trying to find the minimum of the function using GNU scientific library, package Multidimensional Minimization. The method I am using is Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm which is ...
1
vote
2answers
152 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} +...
1
vote
2answers
140 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 ...
1
vote
1answer
69 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 ...
1
vote
1answer
888 views

An efficient way to convert between MKL and Armadillo types

We use Armadillo a lot in our code but there are places where we prefer to use MKL directly from Vector Math Library. We have cx_vec i.e. vector of doubles. But the exp function of armadillo uses std::...
1
vote
1answer
91 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.
1
vote
1answer
116 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. ...
1
vote
1answer
148 views

Finding the lowest $n$ eigenvalues of a band-diagonal Matrix

I have a real sparse matrix of the form $$ \left( \begin{array}{ccc} h_{11} & h_{12} & 0 & h_{14} & & & \\ h_{21} & h_{22} & h_{23} & 0 & h_{25} & & ...
1
vote
1answer
575 views

Can TETGEN generate triangulation of a 2D point set?

I would like to link my Fortran 90 application to a library which would give me Delaunay triangulation (for a 2D set of points) and tetrahedralization (for a 3D set of points). As suggested in Fastest ...
1
vote
1answer
153 views

Is OPENFOAM a good idea for direction/operator splitting in parabolic equation

I would like to know if I should switch to OPENFOAM for my task. I work only with Cartesian grids, right now in 2d, rectangular domains only. If $\mathbf{w} = (w_1, w_2)$ and suppose I want to solve ...
1
vote
1answer
2k views

Free HFSS alternative to create geometry using python

I am using a python script to create wirebond interfaces in Ansys HFSS. Variables define the board, wirebond, and package geometry. To simulate a new wirebond, I just edit the geometry variables and ...
1
vote
1answer
570 views

What kinds of size of matrix A that CHOLMOD can solve Ax=b

CHOLMOD is very fast, but I am just wondering what kinds of size A such that it can solve Ax=b. I have a A of 200,000 * 200,000, but it outputs errors" problem too large". I am very appreciated if ...
1
vote
0answers
119 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 ...
1
vote
0answers
33 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 ...
1
vote
0answers
58 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 ...
1
vote
0answers
217 views

Solving complicated coupled ODE using RK4/ODE45 in Matlab

I have the following coupled differential equations also known as Guiding Center Approximation. It is used to explain the position- and velocity change of particles (electrons and protons, N = 1000) ...
1
vote
0answers
43 views

Software suggestion for simulating the stacking of sedimenting rods

I'd like to simulate the following problem: Define some square, horizontal and hard area onto which cylinders (aspect ratio R) sediment. Preferably, the source of cylinders sequentially generates N ...
1
vote
0answers
84 views

Spherical Harmonics: band-limited representations of a vector field on a sphere

I have used pyShtools in the past to expand scalar functions to spherical harmonics and to synthesize band-limited representations of them. However, I am not too sure how to achieve this for a vector ...
1
vote
0answers
61 views

Book Recommondation for the time-dependent Schrödinger equation [duplicate]

Can you recommend a good book that discusses several methods for the numerical solution of time-dependent and time-independent Schrödinger equation? I have searched the internet several times but ...
1
vote
0answers
327 views

What are alternatives to openbabel to convert CML file to image?

I recently started to perform natural resonance theory (NRT) analysis with NBO6. This program may automatically create a chemical markup language (cml) file with the treated structures. Unfortunately ...
1
vote
0answers
68 views

Convolutional Neural Nets for Large Scale Image Classification on Windows?

I need to build some CNN's using very large numbers of photos, to classify which photos contain certain features. I've run into a number of road blocks. As much as I love both Linux and ...
1
vote
0answers
98 views

Which topics are hot in computational science? [closed]

I am accepted to computational science master program. The master program just started to accept students in our university and today each group of 3 students was assigned to an advisor teacher (we ...
1
vote
0answers
43 views

Interior nodes of a closed graph?

Does anybody know if any graph partitioner library such as Metis, Scotch, or Zoltan can (besides splitting a domain), differentiate between internal (i) and boundary (b) nodes?
1
vote
0answers
44 views

Manipulating/Extracting Data and Developing Methods - Language Choice [closed]

As a general programming enthusiast and aspiring Bioinformatician student I have an intermediate understanding of computing (languages) as well as Java, and to a lesser extent C++. Having knowledge in ...
1
vote
0answers
61 views

Understanding the use of Minimum Translation Vector (MTV) for an elastic collision response

So, I'm trying to simulate polygon rigid body physics, both linear and angular. To calculate the MTV is easy in SAT (Minimum Translation Vector), and to use it to adjust position is also easy: ...
1
vote
0answers
179 views

How can i find the coordination number with voro++? [closed]

Could anybody please help with voro++ cause i am new to this software?My problem is how can i find the coordination number of an atom ,cause i checked it for a bcc lattice and it gave me 24 for all ...
1
vote
0answers
62 views

speckle interferometry (or other interferometry) software

This might not be the best place to ask, and if its not could someone please point me to where would be better, but here we go anyway. Does anyone out there know of open source software which can be ...
0
votes
3answers
246 views

CAD like visualisation of 3D vector data?

It looks like MATLAB and Mathematica is often used for post-processing and data visualization of 3D vector data. Now consider you are simulating 3D objects and get out gradient fields etc., is there ...
0
votes
1answer
688 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 ...
0
votes
3answers
716 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 ...
0
votes
2answers
80 views

Software that does naïve or formal simplification of mathematical expressions

Devil-may-care that I am, suppose that I wanted to 'simplify' the following expression, utterly ignoring the fact that it's very naughty to raise various kinds of numbers to arbitrary powers or to ...