All Questions

I am trying to plot the graph of chaotic impulsive neural networks and I have written the following MATLAB code for the same: However, I am getting the Warning: Failure at $t=4.831354$. Unable to ...

I would like to determine the number of negative eigenvalues (inertia count) of the $(N \times N)$ symmetric real matrix $K - \sigma M$, with $K$ a positive-definite sparse matrix and $M$ a positive ...

Every real matrix $A$ can be reduce to real Schur form $T = U^T A U$ using an orthogonal similiary transform $U$. Here the matrix $T$ is quasi-triangular form with 1 by 1 or 2 by 2 blocks on the main ...

I have a time dependent data set where each frame corresponds to a certain date. I need to show the time annotation, much like what Annotate Time Filter does, but show the date instead of time as a ...

Given a fat matrix $B \in \mathbb{C}^{n \times m}$ (where $m > n$) with full row rank, I would like to find (numerically) a full-rank matrix $A$ that minimizes the Frobenius norm of the product $A ...

I have a python implementation of calculating the partial trace over select dimensions. ...

I am trying to do integrals of the type $$ \int d^3\vec{p} \int d^3\vec{p}' e^{-p^2} e^{-{p'}^2}f(\vec{p}, \vec{p}') $$ where $\vec{p}$ and $\vec{p}'$ are three dimensional vectors represented using ...

I am learning OpenCL and have written a preliminary code that will query the machine and find out the platforms and devices associated with it. ...

Relatively new to machine learning, I am looking for the best method to use for classification of sealed-soil from remote-sensing data. As a try-out, I would like to start by identifying streets and ...

There are generic methods for solving systems of ODEs numerically. Are there generic methods for PDEs? If so, what are they? If not, why not? To elaborate... Any set of ODEs can be written in ...

Hy sir my plot is to much fluctuation at smaller values ... I set Precision upto infinity but not effective, Any tip sir

I'm trying to simulate the 2D incompressible Navier-Stokes equations using a finite difference scheme that uses the implicit Backwards Euler method for moving the simulation forward in time. I have ...

I would like to insert elements into a ring (circular) buffer one at a time and maintain a permutation array which keeps track of the sorted elements in ascending order. To do this, I have adapted the ...

Too often, code for computational purposes can be slow, buggy, or insecure. What habits and paradigms/frameworks of thought have assisted you in your journey to create beautiful code?

I am trying to compare the effectiveness of a histogram for density estimation, by seeing how well it approximates the PDF of a normal distribution. I make use of the concept of entropy, which is ...

I want to do somethings similar to the plot found at the bottom of this blogpost, which I found via this post in ParaView, which seems to have been the original Application used to generate the plot. ...

A certain filter I'm writing uses two different kernels. The Fejer kernel (which is common) and the Jackson kernel: $$ \Delta_T(x) = T \,\left( \frac{\sin \pi T x}{\pi T x}\right)^2 \quad\text{and}...

I am trying to sort data following a bivariate distribution into a numpy histogramdd, where each bin should contain the same number of data points (to the nearest whole sample). I expect that some ...

I'd like to find an algorithm that can solve the following problem: Consider 4 groups of numbers: Group 1: [10, 100, 1000], Group 2: [101, 15, 2000], Group 3: [20, 1500, 100], Group 4: [150, 3000, ...

I'm new to SOCP and want to try to get familiar with the format and how to solve it with cvxopt in python. However, for a simple toy example I'm struggling to get ...

I would like to use automatic differentiation to calculate gradients to function written in numpy. I've come across a number of packages, including autograd tangent chainer But none of them seem ...

The Navier--Stokes equations are axially symmetric, so with symmetric boundary conditions, how can features such as Karman vortex streets develop? I understand that in reality symmetry does never ...

I am trying to solve numerically a constrained optimisation problem in MATLAB, and I am wondering how the fmincon function calculates gradients when one isn't ...

This is a problem I am encountering in a research project. I have thought of a naive approach to solve it which relies on many assumptions, is not guaranteed to work, and would be tedious and ...

I'm interested to derive the total energy balance from Chapman-Enskog analysis of lattice Boltzmann equation (LBE). I know, I should go to the second moment of LBE (zeroth moment gives mass ...

Assume one has a triangular sparse matrix and want to solve $Lx=b$ where $b$ and $L$ are known. This can be done easily by using forward substitution when $L$ is a lower triangular matrix. Forward ...

I am using a .poly file to generate a volume mesh using TetGen. My surface mesh has one hole and I have defined that in the .poly file. Every time I run TetGen it is giving me the following error "...

Connected to this question here on Computational Science, I've posted a follow-up question on how to solve a PDE using an implicit scheme like Crank-Nicholson in general in this question on SO. But I ...

For example, for 1D Burgers equation $$ u u_x = 0 \\ $$ equivalently, $$ \frac{dF(u)}{dx} = 0\\ F(u)= \frac{u^2}{2} $$ If I want to obtain $A_{ij},i\ne j$ for two DOFs ($U_i$ and $U_j$) of two ...

Sorry for disturbing you, my friends. Recently, I am reading books on Rayleigh beam theory where the rotary inertia can be taken into account without introducing rotational degrees of freedom. For ...

Consider the XDMF file below. How can I replace the explicit x-vector 0.0 1.0 2.0 3.0 in the geometry block by a reference to an ASCII file ...

What scientific problems can be simulated with computers that couldn’t be simulated 10 years ago? I’m particularly interested in cutting-edge scientific simulations, which wouldn’t have been possible ...

I'm trying to use the excellent Schrodinger Python class by Jake VanderPlas (https://jakevdp.github.io/blog/2012/09/05/quantum-python/) to simulate a wave packet within a moving Gaussian potential. I ...

I am working on a 2D unstructured code in C++. I am using gmsh to generate a 2D unstructured mesh and reading it into my program with a library called ...

EXOTIC STATS PROBLEM ; MODE, FUZZY CLUSTERS, ETC Hi I'm working on a math problem and not sure how to approach it. Trying to enumerate, rank and extract most common numeric ranges from a list, with ...

In Finite Difference method or Finite volume textbook. Dispersion/Dissipation can be analyzed by set $u = u_0\exp{\omega t +\mathbf{kx}}$。 However, I cannot find something about this kind of analysis ...

I want to solve a QCQP in Python. It is a problem from finance: maximise return (linear function) given some linear constraints and one quadratic constraint that turns it into a QCQP. Formally, $$\...

I know Lax-Milgram theorem is fundamental to FEM. But it did not explain what will happen if coercivity is not met. My understanding is if it is met, eigen value of the operator (or its corresponding ...

I have a 7-14 dimensional piecewise linear cost function I'd like to minimize with two quadratic terms of the form: $$ f(X) = X^tCX + d \sum_i |x_i-x^*_i|^2 + \sum_i P_i(x_i-x^0_i) $$ $$ \sum_i x_i ...

I am struggling a bit with the concept of preconditioners for iterative solvers and how to implement them efficiently. The literature mostly provides methods to create a preconditioner matrix $M$ (...

I have read this question and answer – Interpolation of scattered data to a regular grid in python and I am doing something similar as I have temperature values of the atmosphere at different heights ...

It is so confusing, especially when I learns discontinuous galerkin method in broken Sobolev space and weak Dirichlet boundary condition. If the trial function is chosen with homogeneous boundary ...

I have 5 million items that have 10 features (all continuous and not categorical) each and would like to select a small subset of these items. Ideally, I want to manually specify 10 features of my own ...

What is the difference between Simulation-based Optimization and PDE-constrained Optimization? Would studying a text on Simulation-based optimization be sufficient to understand and apply both?

I'm making a 2D FEM program (using only quad elements), and after vtk's examples to assign scalars to the elements of my mesh, I got no good results. Basically, I have 3 arrays: The first one is the ...

I want to use artificial neural network(ANN) for solving non-convex optimisation problems. How do I map the constraints and the objective functions in the ANN architecture?

I am using the CUSP CG solver and I ran it on couple of sparse matrices from the University of Florida sparse matrix collection. The solver was able to solve non positive definite sparse matrices. My ...

I have carried out a CFD simulation (with finite volume method) to investigate the unsteady force enforced to the vehicle body. The horizontal tail keeps flapping in sinusoidal function. As a result, ...

My question is about how I can solve a coupled system of ODE's, and print out the variables in a plot. I am solving for an q value and an e value, seen in this set of coupled ODE's below: $$ \begin{...

I'm trying to implement Barnes-Hut algorithm, with a binary tree. My initial conditions are a uniform mass distribution in a sphere with radius $R$. How can I create uniform dots distribution in a ...