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0answers
31 views

How to code on matlab for nonlinear systems?

How to code on matlab to solve arbitrary(not polynomial)nonlinear multivariable system of equations?like equations tagged under nonlinear systems of equation(see my equation I tagged)
1
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2answers
80 views

What sparse linear programming solver it is better to use?

I have the following LP problem: $$ \min \limits_{\varepsilon, x_{1}, \ldots, x_{n}}f(\varepsilon, x_{1}, \ldots, x_{n}) = \varepsilon \;\;\;\;\; s.t. \;\;C x \geq 0, \;\; x_{i}^{0} - \varepsilon ...
4
votes
1answer
86 views

Solver suggestion for many small quadratic problem in C++

I have a C++ program/model that in some parts already use IPOPT (with ADOL-C and ColPack) to solve some pretty large non linear problems. Now in an other part of the program I need to solve a large ...
0
votes
0answers
76 views

Salome-Meca, and using a custom solver

I just downloaded Salome-Meca build. I've used Salome previously so I'm competent enough to build geometry, create basic meshes and make surface groups for boundary conditions. What I'm not familiar ...
1
vote
2answers
97 views

Determine the step size in a differential equation numerical solver

How can we define the precision we require in a numerical differential equation solver? What is it that I have to optimize to know? And how do I know that I'm at a sufficient time-step value? For ...
7
votes
2answers
102 views

How do you numerically solve a multivariable ODE system with different time steps per state variable?

If you have a large multivariable ODE system, and certain processes occur at a much smaller time scale, how can you implement a solver that uses smaller time steps for state variables involved in fast ...
3
votes
3answers
109 views

Best method to find the zero of a decreasing function numerically

I need to find the zero of a function $f(\lambda)$ which is of the form $\sum \frac{c_i^2}{(1+\lambda d_i)^2} -1 $. I tried using Newton's method, and it works sometimes, but it is higly dependent of ...
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0answers
59 views

A question on CHOLMOD

When I change "cholmod_*" to "cholmod_l_" (because the size of my matrix is large, use "cholmod_" will outputs error"problem too large"), it shows " sparse:error: integer and real must match the ...
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4answers
209 views

Simple FEniCS problem shape mismatch

EDIT: THE ORIGINAL POST DID NOT MAKE MUCH SENSE, SO I ADJUSTED IT Ok, so I have thought about it, googled it and put some more thought into it. This presentation by the Imperial College in London has ...
3
votes
2answers
192 views

Quadratic Programming: Quadprog

Given a real-rectangular matrix $S$ and inorder to solve this simple quadratic programming problem: Minimize $w'S'Sw = ||S w||^2$ over $w$ subject to $e^Tw = 1$ and $w \geq 0$ using a solver I ...
4
votes
1answer
155 views

Solving Coupled ODE eigenvalue problem

I've been trying to find some resources that would help me figure out how to numerically solve a coupled system of ODEs which is also an eigenvalue problem. The system is something like: $ \tag{1} ...
5
votes
1answer
177 views

Poisson solver on unstructured mesh

For the 2D Poisson equation, there exist on finite difference mesh, some code taking $O(n \log(n))$ operations to solve it on a mesh with $n$ nodes. They rely on Fast Fourier Transform or Block Cyclic ...
4
votes
3answers
504 views

CPU benchmarks for numerical kernels

CPU benchmarks available online mostly focus on desktop apps/games and rarely on serial/parallel numerical kernels, specially sparse ones (e.g., MatMult). Some benchmarks like NAS/SciMark exists but ...