# All Questions

9,115 questions
Filter by
Sorted by
Tagged with
579 views

### Fortran round-off error with floating point operations

I have simple code, which flags nodes with in region enclosed by cylinder. On implementing the code, the result is mild tilt of the cylinder observed case with $\theta=90^{\circ}$. The algorithm for ...
74 views

127 views

### Quantum Chemical Calculations is there a book for which method to use with what problem?

Does anyone know of a book that will outline which quantum chemical methods are appropriate for what problems? I am trying to make informed choices before I start using computational resources. It is ...
603 views

### Positive definite matrix in CVX

I'm trying to use CVX to solve SDP problem. I have a constraint with positive definite matrix, but if i read the document of CVX, I can only find variable with positive semidefinite matrix. Can anyone ...
97 views

179 views

### Is it possible to show global conservative properties FEM as it is done in FVM?

I know that in FVM, it is possible to show that a discretisation scheme is conservative by adding the discrete terms over a few control volumes and showing that all terms cancel apart from those ...
4k views

### Simple java gravity simulation

I'm trying to write a class that uses Newton's law of Gravitation to work out the field of a planet. I've tested my code by inputting values for Earth, for purely vertical motion, so I should get g = -...
926 views

I would like to code for a quadtree type meshing but don't know how to do. If anyone can help or can share any starting code?
510 views

### Variational Monte Carlo: Variational energy is lower than ground state energy

I'm writing a VMC simulation for hydrogen and helium atoms, but in both my codes my variational energy for certain wavefunctions is not only statistically different from my expectation value, but it ...
180 views

### Solving a quadratic pseudo-boolean optimization problem where the integral constraints are relaxed

Quadratic Pseudo-Boolean Optimization (QPBO) problem: Problem 1. Minimize $\sum_i a_ix_i + \sum_{i<j} a_{ij}x_i x_j$ subject to $x_i\in\{0,1\}\forall i$. Consider the following problem, where the ...
530 views

### Comm argument on MPI_Reduce in FORTRAN giving unusual results

I'm putting together a very simple integration program in FORTRAN using MPI. I have done this with C and all was well. However, in my "MAP_REDUCE" call, the comm argument seems problematic. I have ...
36 views

### Support Vector Machines to use after Classification?

I'm a little bit about the SVM. I'm actually understanding for which purpose Support Vector Machines are used. The aim is to find the biggest (best) hyperplane between two different data clusters. The ...
730 views

### Solving coupled differential equations and Algebraic equation in MATLAB

I want to solve a system of 7 coupled differential equations and 1 algebraic equation in MATLAB with the method of lines. I could do it for each independent equation with some assumptions, but I can'...
159 views

171 views

### fast gradient method for convex piecewise linear function

What is the state of art gradient based algorithms in convex optimization solving non-smooth piece-wise linear functions? Thank you. EDIT: It is different from one of my previous post in the sense ...
80 views

### Mathematical error when attempting to represent step function using fourier series

I am attempting to work through a very simple problem. Determine the Fourier series expansion for the following heat PDE problem with ICS and BCS: $$u_{t} = \alpha^2u_{xx}$$  u(0, t) = u(L, t) =...
2k views

### Gonzalez algorithm

I'm getting confused about implementing the Gonzalez algorithm for k-center clustering. The algorithm is : let $S$ be a data set Choose $z_1 \in S$ arbitrarily. Number $z$ is center. (In general ...
212 views

### Strict Feasibility in Interior Point Methods

As we know, in the interior point methods, all the iterates have to be strictly feasible. I implemented an affine scaling interior point for nonlinear objective functions. For small examples (2D), it ...
627 views

### Interpolating 3D Array non-monotonic data in MatLab

I am working on creating a program for simulations where three variables are parametrized, and we modify one parameter while keeping the other two constant. An example array looks like this when ...
1k views

### Temperature dependent 1-d conduction in Python?

I'm trying to write a Python code that is a numerical solver for 1-d heat conduction (using FVM) with a temperature dependent thermal conductivity. The solver has three functions I need to iterate ...
I need to solve this integral: $M = \rho h \int_0^a \int_0^b N^2 \ dx dy$ where $N$ is defined as: \$N = sin\left(\dfrac{\pi}{4}\eta +\dfrac{3\pi}{4}\right)sin\left(\dfrac{\pi}{4}\eta +\dfrac{3\pi}{...