All Questions
35 questions
2
votes
1
answer
314
views
Quadratic Eigenvalue Problem
Is SLEPc really the only C/C++ package that provides a solver for the Quadratic Eigenvalue Problem (QEP) out of the box, using sparse matrices?
- 294
0
votes
1
answer
242
views
Assign and print the results of CHOLMOD package
I am trying to solve a simple working example, a linear system $Ax=b$, where $A$ is sparse SPD and $b$ is dense, using CHOLMOD.
...
- 294
1
vote
1
answer
403
views
What language are best for creating data compression algorithms except for C/C++?
I've been trying to implement data compression algorithms in python, but I just can't get mine as fast as the other algorithms other have made. So I've decided on using C since I've asked people about ...
- 153
1
vote
2
answers
2k
views
Recommendations for ODE solvers for stiff equations
I'm continuing the research of a former Ph.D. student in my group requiring the solution of a system of ODEs. On a technical note, they wrote:
The system of Boltzmann equations behaves numerically ...
- 105
4
votes
2
answers
663
views
Evaluation of real-valued confluent hypergeometric function with specific complex arguments
In my C++ code, I need to evaluate the confluent hypergeometric function ${}_1F_1(a,b;z)$ with complex arguments in a special case. More precisely, I have to compute
$$
e^{-i\phi}{}_1F_1(\ell+1+iZ,2(\...
- 61
1
vote
2
answers
185
views
Need software for generating self-avoiding random walks on a tetrahedral lattice
I am looking for FOSS code that can generate self-avoiding random walk trajectories on a tetrahedral lattice. The purpose of the exercise is to create random conformations of model polymer chains that ...
- 321
10
votes
1
answer
1k
views
How to document math formulations in scientific computing codes?
I am writing the code relate to math.
There is some complicated math formulation in the project.
Directly writing the calculation code leads to hard understanding; thus I want to comment on the ...
- 323
4
votes
3
answers
236
views
GPGPU computing, software selection
I am using an existing GCC C++ x86 Qt application that filters, displays and stores results computed by some C code. Since the computation by now got too complex for CPUs I intend to port the small C ...
- 163
6
votes
4
answers
3k
views
Efficient eigen-decomposition of covariance matrix
I am looking for an C/C++/Python algorithm implementation that calculates eigenvalues and eigenvectors of a symmetric, positive semidefinite covariance matrix.
A general-purpose eigen-decomposition ...
- 201
0
votes
1
answer
258
views
Looking for a converter of AMPL/GAMS models into C code
I've done an extensive web search, but could not find an option. Conversion between model formats is available, but conversion of objective function and constraint equations into C code seems absent. ...
- 201
1
vote
1
answer
519
views
I've developed a derivative-free optimization method, looking for comments
Here is the URL: https://github.com/avaneev/biteopt
I've tested it on numerous global optimization benchmarking functions (included), and on real-world hyperparameter optimization problems I have. ...
- 201
2
votes
0
answers
92
views
Looking for a version of DSDP that is less prone to integer overflows than the original
I am working on a problem that involves semidefinite programming (constrained optimization of fairly large positive definite matrices). The software is written in C++ and calls DSDP 5.8 to solve the ...
- 321
2
votes
0
answers
844
views
Using C/C++ for Markov chain Monte Carlo (MCMC) methods
I'm working on optimizing the parameters of a mathematical model to fit experimental data, using an existing formula for the likelihood of observing the data given a set of parameter values. At the ...
- 31
4
votes
1
answer
186
views
Using GSL for basic operations
I am learning C/C++ for Scientific Computing and I have a question regarding the usage of scientific libraries for basic operations.
Suppose I have to write a small program in C for a bioinformatics ...
- 404
2
votes
0
answers
219
views
lightweight implementation of semiempirical quantum chemistry (e.g. MNDO,AM-1,PM3)
I'm searching for semi-empirical quantum chemistry solver which would be easy to integrate into my own software. I found a few implementations which can be in principle used e.g. MOPAC, ORCA, SQM some ...
- 937
4
votes
1
answer
3k
views
Simple open-source Quantum chemistry or DFT code in C/C++
I know lot of density functional packages in fortran, including one which we are developing in our group (Fireball-DFT) but I don't like fortran very much and I would like something which is easier ...
- 937
1
vote
0
answers
134
views
Problem in analyzing the program of Gauss Jordan Inverse problem
I had to code a program which calculates Inverse of a matrix by Gauss-Jordan Inverse method , I was trying to analyse the program and then code it myself.
the link
http://hullooo.blogspot.in/2011/...
- 229
1
vote
0
answers
76
views
Is MATLAB feasible for app deployment versus lower level languages [duplicate]
MATLAB/Octave is a pretty useful language for prototyping scientific computation use cases, however I would like to know if the sheer nature of being a high level language bottlenecks how fast the ...
- 111
1
vote
2
answers
275
views
Programming language for HPC [closed]
I'm planning on building a program that will carry out HPC. I'm aware that C/C++ is significantly better than Python in terms of the speed of computation. However, I'm not yet proficient in C/C++, so ...
- 11
5
votes
3
answers
1k
views
What do C, C++ and Java have that Fortran 2003 don't? [closed]
As you may know, Fortran is widely and longly (?) used in science. I've heard a lot of people saying that we natural scientists should all migrate to C++ or Java. I've seen people increasingly ...
- 207
8
votes
2
answers
1k
views
Library with polylogarithm function [duplicate]
I am looking for a reliable library where I can find polylogarithm function and newton/secant method for solving non-linear equations. Basically I have something like this:
...
- 181
2
votes
2
answers
1k
views
Kummer's confluent hypergeometric for complex arguments in C/C++?
I need to evaluate Kummer's confluent hypergeometric function for imaginary arguments:
$$_1F_1(a,b;ix)$$
where $i$ is the imaginary unit, $a,b,x$ are real, and $a,b>0$. Is there a routine ...
- 1,739
2
votes
1
answer
639
views
Recommendation for C/C++ library which offers Schur complement functions?
I need to find C/C++ libraries which offer function for computing Schur complement. I know about MUMPS and Pastix, but I need more of them to compare them in my research.
Do you have any experience ...
- 141
1
vote
0
answers
105
views
Elemental vs DPLASMA
I want to use one of these two libraries into my C++ project to basically invert a dense matrix (with Cholesky). Of course, I am interested in a distributed environment.
Both libraries seem nice so ...
- 113
-3
votes
1
answer
446
views
Solving electron density function for Hydrogen and drawing in 3D
I recently stumbled upon interesting site that has interactive 3D representation of radial electron distribution (atomic orbital).
here is the url: http://winter.group.shef.ac.uk/orbitron/AOs/1s/e-...
8
votes
3
answers
8k
views
Should I pass command line arguments to MPI_Init or not?
When writing MPI 3.0 code, should I pass argc and argv to the MPI_Init call or not, and why?
...
- 1,085
0
votes
1
answer
668
views
Fastest linear solver for sparse positive semidefinite, striclty diagonally dominant matrix
What is the state of the art for fastest linear solver for sparse, positive semi definite and strictly diagonally dominant matrix with N varies from ~700 to ~3000, and about a 1/16 of the matrix is ...
- 93
14
votes
4
answers
5k
views
Looking for Runge-Kutta 8th order in C/C++
I would like to use Runge-Kutta 8th order method (89) in a celestial mechanics / astrodynamics application, written in C++, using a Windows machine. Therefore I wonder if anyone knows a good library / ...
- 277
3
votes
1
answer
904
views
Accurate implementation of the logarithm of the incomplete Beta function in C++?
I need an accurate implementation (for use in C/C++) of the logarithm of the incomplete Beta function:
$$\log \mathrm{B}(x,y;\alpha,\beta) = \log \int_x^y t^{\alpha-1}(1-t)^{\beta-1}\mathrm{d}t$$
...
- 1,739
13
votes
5
answers
1k
views
Compute $(e^x-1)/x$ near $x = 0$
The function $f \colon x \mapsto (e^x-1)/x$ has singularity near $x = 0$. That singularity can be lifted, though: for $x = 1$, one should have $f(x) = 1$, since
$$
e^x = \sum_{k=0} \frac{x^k}{k!}
$$
...
- 233
11
votes
3
answers
1k
views
Testing if two 12x12 matrices have the same determinant
I am given a $12 \times 12$ matrix $Q$ that is symmetric, invertible, positive definite and dense. I need to test if $$\det(Q) = \det(12I-Q-J) \; \; (1)$$ where $J$ is the all ones matrix.
I am ...
- 468
3
votes
2
answers
124
views
Are matlab C library versions backwards compatible?
I have some C++ code that links to matlab2008b. Are matlab 2012a and 2012b backwards compatible with 2008b?
If it's not trivially compatible, are there some simple steps to make it compatible?
- 3,355
9
votes
3
answers
2k
views
Recommendations for a lightweight/no-install C or C++ based dense linear algebra solver
Most of my programming is one-off research codes in C for my own use. I have never distributed any code to other than close collaborators. I have developed an algorithm that I am publishing in a ...
- 193
3
votes
3
answers
627
views
How to obtain finite difference, which is continuous
I want to calculate a finite difference (something like this SO Post). My data is as follows: I have x-values that are powers of two (4, 8, 16, 32 and 64). Corresponding to them are y-values, such ...
- 133
6
votes
2
answers
2k
views
Which libraries have good implementations of Basis splines?
I'm looking to use the finite element method with B-splines as my function basis. Which C/C++ libraries have good B-spline support?
Specifically, I'm looking for an implementation of a stable ...
- 3,355