0
votes
0answers
2 views

FEM with soil slope

I what to calculate displacements, stress and strain in a soil slope with a FEM script. The slope moves like a laminar flow. Can you suggest me some bibliography on this problem? I've already look on ...
2
votes
1answer
36 views

How to test convergence of an algorithm for constrained optimization

I am applying an iterative method (projected newton) to an optimization problem. Theoretically, the method should converge linearly. I would greatly appreciate it if you could share how should I test ...
0
votes
0answers
19 views

The solution found by the optimization function when exitflag is negative

I'm using Matlab's fmincon to solve a constrained nonlinear optimization for varying sets of parameters in the objective function. I have 2 parameters and have 400 unique combination of these 2 ...
0
votes
0answers
7 views

Finding correlations between sparse data with different temporal bases

The problem was one that came up during a standards committee meeting. If have one channel of data sampled every 100ms to record fault codes on a system (say an gasoline engine). It records value ...
0
votes
0answers
15 views

convergence interval of an infinite series without the general term

I am trying to find the convergence of an infinite series of which I do not have the nth term. Instead of applying the ratio test for the nth term, I divided the first two terms, then the next two and ...
0
votes
0answers
35 views

how do I know is my GPU work?

When I did my simulations I am test my Nvidia Tesla c2075 if its work or not ? so according to my attached photo , that's mean its not working ? I am already enable GPU on starting Fluent 15
0
votes
1answer
47 views

difference of polytopes in $\mathbb{R}^n$

Is checking the equivalence of two convex polytopes $p^{s}$ and $p^{t}$ NP-hard? $p^{s}= CH\{ \cup <p^{s,a_1},...., p^{s,a_m}> \} $ // CH is convex hull computed on union of a polynomial ...
0
votes
1answer
59 views

Tanh-sinh quadrature numerical integration method converging to wrong value

I'm trying to write a Python program to use Tanh-sinh quadrature to compute the value of \begin{equation} \int_{-1}^1 \frac{dx}{\sqrt{1-x^2}} \end{equation} but although the program converges to a ...
0
votes
1answer
46 views

solving a non-linear equation with integrals involved

I would like to solve the following equation, wrt $n(e)$ $$f(n(e))=g(n(e)) + \int w(n(e))de $$ The integral there it confuses me. Any suggestion on how I can implement this on a the computer (I am ...
3
votes
2answers
47 views

Cloud solutions for microscopy image analysis

At our research facility we routinely perform what are called PALM (Photo-activated localisation microscopy) or STORM (stochastic optical reconstruction microscopy) experiments. You can read all ...
5
votes
1answer
27 views

What are the numerical methods for huge polynomial systems?

Let a system of $n$ polynomial equations of degree $d$ with $m$ variables. I'm interested in a sparse system with $d = 3$, $n \sim 2000000$, $m \sim 50000$ and integer coefficients. What techniques ...
0
votes
0answers
13 views

What is the difference between continuous-time waveform relaxation(CWR) and discretized waveform relaxation?

What is the difference between continuous-time waveform relaxation(CWR) and discretized waveform relaxation? I am just confused ...
2
votes
0answers
66 views

Pre calculate mathematical expressions in Fortran 90

Is there some flag to let the Fortran compiler pre calculate a math expression before compiling it?. I have to write expressions that contain many small 4x4 matrix multiplications. The thing is, most ...
5
votes
2answers
156 views

Understanding the cost of adjoint method for pde-constrained optimization

I'm trying to understand how the adjoint-based optimization method works for a PDE constrained optimization. Particularly, I'm trying to understand why the adjoint method is more efficient for ...
0
votes
0answers
26 views

Algorithm for porosity based CFD mesh

I am writing the pre-processing program for a porosity based CFD project. I have a mesh made of cubes, and need to import an object (a stl file: triangular mesh, not solid) over it. The cubes will ...
1
vote
1answer
36 views

Open several dependent functions in matlab with scripting

I have several matlab functions and one script that call those functions. Suppose that they are 'a.m' 'f1.m' 'f2.m' and 'f3.m'. The script 'a.m' must open the functions files when it is manually ...
1
vote
1answer
67 views

How to minimize the artefact of a cartesian to polar transform followed by a polar to cartesian transform?

I'm transforming cartesian images into polar images. (x,y) => (angle, radius) I fill the polar image by iterating on each of its pixels and filling them by doing the reverse polar transform. For a ...
0
votes
1answer
17 views

Non linear system of equations with discretization on k-space

I want to numerically solve the following system of differential equations at the steady state: \begin{equation} \begin{aligned} \frac{\partial \rho_{11\mathbf{k}}}{\partial t} =& ...
4
votes
3answers
72 views

Discrete Poisson Equation with Pure Neumann Boundary Conditions

I'm trying to implement the Helmholtz-Hodge Decomposition in 2D, which states that a vector field is composed by a rotational free component, a divergence free component and a harmonic component. ...
1
vote
2answers
45 views

use Matlab's PDE toolbox to solve PDE with variable coefficients [closed]

I'm new to the PDE toolbox in Matlab. From the PDE specification window of the toolbox, it looks like one can only solve PDE with constant coefficients. How can ...
0
votes
1answer
43 views

Calculating periodicity of a pseudo random number generator (Middle-square method) [closed]

Below is a Python code that calculates the periodicity of the middle-square method for a given 4 digit-numbers: ...
1
vote
0answers
37 views

Issues with Open MPI [closed]

Not sure if this question is more appropriate for StackOverload, but I'm guessing a bunch of people here have experience with MPI2, so thought I would try here first. I have some large dense complex ...
4
votes
1answer
91 views

Numerically compute one-to-one mapping

I have a set of points defined by their coordinates $(x_1,y_1)$ after changing some parameters of the problem I obtain a second set of points defined by their coordinates $(x_2, y_2)$. There exists a ...
0
votes
0answers
12 views

Any software that can symmetrize input sets?

Is there any software that contains symmetrization techniques ex. polarization, Steiner Symmetrization etc. I suppose not. Which software would you suggest for rigid transformations? Thank you
2
votes
1answer
105 views

Comparing Eigenvectors, Mathematica vs. Matlab

I am trying to create the same out puts in Mathmatica and Matlab, however I am running into trouble aligning the eigenvectors with the eigenvalues, I think the Matlab is doing something slighly more ...
1
vote
3answers
65 views

rank-deficient NNLS

I want to find the minimum-norm solution to a rank-deficient least-squares problem, subject to positivity constraints, e.g. $$\min_x\ \|x\|^2 \quad s.t.\quad Ax = b,\ x \geq 0$$ where $A$ is large, ...
0
votes
1answer
32 views

Signal balancing using SVD: notations and implementation in R

Hibbs et. al use SVD to balance the strength of different underlying signals in gene expression data using the following decomposition: $X_{m*n} = U_{m*n} \Sigma_{n*n} V^T_{n*n}$ In this case $U$ ...
0
votes
0answers
23 views

Convex hull and cartesian Product

Under which conditions, the cartesian product of some closed and bounded polytopes is equivalent to their convex hull?
1
vote
1answer
44 views

Fast way to compute all eigenvalues of a dense Hermitian matrix

I am finding the eigenvalues of dense NxN Hermitian matrix which is calculated from a density operator in quantum physics. All the eigenvalues are needed as I need to calculate the sum of the absolute ...
11
votes
3answers
157 views
+50

What is the current state of the art in solving higher dimensional parabolic PDEs (multi-electron Schrödinger equation)

What is the current state of the art for solving higher dimensional (3-10) parabolic PDEs in the complex domain with simple poles (of the form $ \frac{1}{|\vec{r}_1 - \vec{r}_2|}$) and absorbing ...
2
votes
1answer
156 views

0,1 binary polynomial programming

Is there a mathematical optimization branch that explicitly tries to optimize this (type) problem? $$\eqalign{ & \min \cr & \sum\limits_{i = 1}^N {(J*s[i] + {J_1}*s[i]*s[i + 1] + ...
0
votes
1answer
31 views

Appropriate algorithm for (non-linear) ODE with integral equilibrium constraint: collocation?

I have a problem of the following structure: For some scalar $g$, functions $F(z)$ and $h(z)$ defined on $[0,\bar{z}]$ , and a non-linear operator $\phi(F,z)$ (in reality, $F$ and $h$ are vector ...
0
votes
1answer
40 views

Permission denied with diary command

I am trying to use the diary function in Matlab: ...
1
vote
1answer
56 views

Lua and Fortran (or Python) I/O

I am writing a global climate simulation software system. My idea is the following : At the top of everything, I interface to the OS using D, a very powerful language for compile time code ...
0
votes
0answers
17 views

COMSOL: String vibration modeling using Wave Equation PDE

I am learning comsol and already could make the vibration of a string in 1D (geometry used there was an interval) - I saw 2D plot and the string was vibrating, also I could do the same in 2D ...
2
votes
2answers
49 views

Suggestions for open source C++ library for medium scale non-linear solver

I need to find the root of a nonlinear system (which comes out of collocation, so I will change the order to test). I will likely have about 50-300 variables, and the Jacobian is going to be ...
1
vote
1answer
28 views

Solving a problem using multiple threads using CLP

Is it possible to run Clp on multiple threads using Julia and JuMP?
2
votes
1answer
73 views

Levenberg-marquardt: How to calculate the jacobian with fixed parameters

So I'm working on a fitting algorithm using the levenberg-marquardt algorithm and I'm a bit stumped as to how to handle fixed parameters. Looking around at other code, like the minpack version of the ...
2
votes
4answers
110 views

Open source auto-differentiation for MATLAB?

Are there any open-source auto-differentiation libraries for MATLAB? I am aware of commerical packages such as http://tomopt.com/tomlab/products/mad/ and plenty of C++ libraries, but I can't find much ...
9
votes
2answers
148 views

Is it well known that some optimization problems are equivalent to time-stepping?

Given a desired state $y_0$ and a regularization parameter $\beta \in \mathbb R$, consider the problem of finding a state $y$ and a control $u$ to minimize a functional \begin{equation} \frac{1}{2} ...
3
votes
1answer
53 views

Does it make sense to build ATLAS from source on a cloud machine?

ATLAS is an extremely popular linear algebra library. When you install ATLAS from source, it tries to automatically tune a number of parameters to give you the fastest code. Does it make sense to do ...
0
votes
0answers
43 views

ode45 solver MATLAB improve time

I am numerically simulating the Mathieu equation using ODE45 and I have to keep changing the parameters delta and epsilon for each simulation to get the required peiodic solution. Following is the ...
1
vote
1answer
33 views

eigenvalue of small symmetric matrices

If I am to solve a symmetric eigenvalue system $A=QDQ^T$, where $A\in\mathcal{R}^{n\times n}$ and $n$ is small (in the range 4 - 64); I want all the eigenvectors and eigenvalues; There are two major ...
0
votes
0answers
25 views

Generating start point in a systematic manner for fmincon

I'm trying to generate start points for my optimization problem in Matlab. At this point Im not worried about feasibility but only a fast way to generate the points from which I could test the ...
1
vote
0answers
32 views

Generating Hessian of the Lagrangian with dynamic number of nonlinear constraints in Fmincon

I'm using interior point algorithm for solving a nonlinear optimization problem and want to provide Hessian of the Lagrangian as part of fmincon to speed up the process (running couple of thousand ...
0
votes
1answer
31 views

OpenCL C Matrix Multiplication over Multiple Runs

I am attempting to translate a dgemm / MPI matrix multiplier onto the GPU through OpenCL C. My issue is that the code below gives the correct output for a 9x6 matrix being multiplied by a 6x450 ...
0
votes
0answers
37 views

Fast way to compute barycentric lagrange interpolation

Is there any fast way to compute the barycentric Lagrange interpolation using matlab? something more faster than using repmat instead of for loops
0
votes
1answer
24 views

prove optimality only by cutting without branching (gurobi)

I have a MIP which I know the solution almost for certain. I want to use gurobi to prove that the true solution (even if it is not the one i provide) shall not lie more than 0.5% deviated from the ...
2
votes
3answers
154 views

Books on mathematical foundation of finite element methods

After reading three books about finite element method, with two of them covering also finite volume and grid generation, I found myself lost when I have to discuss these topics with library developers ...
0
votes
0answers
31 views

How to create rotating obstacle [closed]

I want to create mesh for channel flow with a rotating cylinder can any one give me the idea? how to do it... I am using fenics FEM solver...

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