Questions tagged [c++]

A powerful object oriented programming language.

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2answers
140 views

General Linear Algebra Wrapper Library

I am currently mulling over the idea of taking a code I currently work with and rebuilding it from the ground up to allow for the use of more efficient programming and numerical techniques. In the ...
5
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2answers
1k views

Three-body problem

I wrote the following program to solve the three body problem (Sun, Earth, Jupiter), initializing the system such that the total angular momentum is 0. The result of the simulation is really bad (and ...
2
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0answers
122 views

Lapack++ for QR algorithm

I have recently started using Lapack++ which I found convenient for my programming purpose, in general. Now, I need to solve a matrix using QR algorithm. I've searched the user manual and I found a ...
4
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3answers
473 views

Literature material discussing generic frameworks to solve PDEs

I am trying to gather literature material to study how people propose to implement generic frameworks to solve partial differential equations in C++. Despite my effort to search the web, the only ...
10
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3answers
3k views

How to build a recursive spline function in C++

At the moment I am working on a differential equation solving method called basis-spline collocation. What I am having trouble with is building a method to build an arbitrary order spline, with the ...
3
votes
2answers
926 views

FEniCS: extracting points from a cell

I'd like to loop over all edges of a simplex (in a mesh). To this end: How can I extract the the points from a cell? This is for the eval method of a C++ ...
0
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1answer
51 views

Cells segregation

There is unstructured grid which contains only quadrangles cells. Each cell has 4 neighbors, and known them (has a pointer to them). I can iterate through all cells in the grid. Some cells are marked ...
3
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1answer
70 views

Library for solving a linear selection problem in a distributed memory machine

I need to solve a very large O(10^10) linear selection problem in a distributed memory machine, is there any library that will solve it for me? In shared memory ...
5
votes
1answer
131 views

Use Butterworth and Chebychev filters

I need to calculate frequency response, phase response and apply to signals the Butterworth, Chebychev1 and Chebychev2 band-pass filters. I'm developing in C++ with Qt, and I'm looking for algorithms ...
6
votes
1answer
2k views

Flexible Mesh Framework

I am looking for flexible and easy to learn mesh framework which provides data structure for representing and manipulating meshes in 2D i 3D. I've already found a few: MSTK https://software.lanl.gov/...
3
votes
2answers
115 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?
9
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4answers
508 views

Hosting site for a small scientific library

For my research work I have been developing a small C++ library aimed at facilitating the communication between C++ computational codes and Octave/Matlab (when the latter is used for post-processing ...
9
votes
3answers
1k 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 ...
3
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1answer
685 views

SQP optimization algorithm tuning advice

I am using a stable version of SQP algorithm from a lib. Parameters setting is left to the developer, althought default values are at hands. I launch solver on very simple optimization problems s.a. ...
24
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4answers
2k views

When should I use C++ expression templates in computational science, and when should I *not* use them?

Suppose that I'm working on a scientific code in C++. In a recent discussion with a colleague, it was argued that expression templates could be a really bad thing, potentially making software ...
7
votes
2answers
640 views

transitive floating point comparison with (absolute) tolerance

I want to compare two floating point numbers for equality relative to a known absolute tolerance. However, this is inside an algorithm I wrote quite some time ago, and I believe the logic of that ...
12
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3answers
1k views

Blaze linear algebra library?

The paper "Expression Templates Revisited: A Performance Analysis of Current Methodologies" in SIAM Journal of Scientific Computing references the "Blaze" linear algebra library. I haven't heard of it ...
6
votes
2answers
543 views

Recommendations for a usable, fast GPL-compatible derivative-free numerical optimization library that can be interfaced to C++

I am dealing with optimization of functions for which I do not have derivatives available, and the optimization is not constrained. I am searching for a high quality GNU Public License-compatible ...
0
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0answers
166 views

Permissive Math Library for Parameter Statistics in C++

I am looking for recommendations for a C++ math library, with a permissive licence, well suited to calculating a wide variety of statistics on segmentations of timebased parameter data. I would be ...
7
votes
1answer
395 views

Generalized least squares gradient of a vector field

For computing the gradient of a scalar field, one can use the weighted least squares method as described in the paper Revisiting the Least-squares Procedure for Gradient Reconstruction on Unstructured ...
6
votes
1answer
2k views

Why does std::complex<> initialize its value to 0 upon default construction?

Doing so strikes me as a waste of time. Consider std::complex<double> *a = new std::complex<double>[1<<28]; This could be near-instantaneous ...
3
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3answers
2k views

What modern OOP features should a computational scientist use? [closed]

Many computational scientists that I know of, including myself for example, are not computer scientists. As such they are often not very well aware more advanced techniques in OOP. On the other hand, ...
12
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3answers
1k views

Efficient tridiagonal matrix algorithm implementation

I am solving a physical problem using implicit numerical scheme. This leads me to solving a linear equation with tridiagonal matrix. I've coded this algorithm from Wikipedia. I wonder if there is an ...
8
votes
1answer
723 views

C++ library for graphs with maximum common subgraph solver

I'm looking for a convenient, free C++ library for graphs that include a solver for the maximum common subgraph (MCS) problem. I'm aware of the Boost Graph Library and LEMON , but neither includes an ...
4
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3answers
457 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 ...

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