# All Questions

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### 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 ...
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### Reference BLAS/LAPACK from NETLIB is twice as fast as MKL for complex numbers

I'm solving the Helmholtz equation using PETSc. I found with the PETSc configure option --download-f-blas-lapack my program runs twice as fast over running it with ...
146 views

### Explanation of LidarBoost Algorithm?

I am trying to understand the LidarBoost algorithm as explained in this paper (PDF warning). My apologies if this isn't the appropriate exchange; I've posted in DSP, but I didn't get a response there, ...
413 views

### Simple turbulence model appropriate for buoyancy-driven cavity like problem

Which turbulence model is suitable for resolving incompressible buoyancy-driven flow of a fluid within an cylindrical ampoule? I prefer turbulence model which is sufficiently simple so that fully ...
183 views

### How to setup a Neural Network?

I have a completely beginner question about the setup of artificial neural networks. Basically it boils down to: How do I put in data and get results? For example, classification: let say I have ...
477 views

### Fenics: time-independent Sine-Gordon equation

Is there a code for the equation $$\frac{\partial^2u}{\partial x^2}+\frac{\partial^2u}{\partial y^2} = \sin(u)$$ or for the sine gordon equation in two dimensions because I want to change some ...
862 views

### Compute lengths of the longest edge of each cell

Having mesh = UnitSquareMesh(2, 2) Q = FunctionSpace(mesh, 'DG', 0) this works as expected ...
3k views

### Genetic algorithm vs conjugate gradient method

I am trying to optimize some force-field parameters in a molecular framework so that the result of simulation comes as close as it can to the experimental structure. In the past, I have written a ...
412 views

### Trajectory Planning: Polynomials as universal, integrable approximation functions?

I'd like to program a trajectory planner, let's say for a robot, and I can pass acceleration commands to the robot, the robot can move in one dimension. The outcome of the planner is now a vector with ...
402 views

### SVD regularization - ray 2D tomography

Sunny day today, isn't it? Please, I need help with my problem. I have written a program to do 2D ray tomography, according to this paper. For the result, I use formula (4.15) from the paper. Now I ...
634 views

### Fenics : boundary condition

`I am working on a problem found here " http://www.caesarsystems.co.uk/NAFEMS_benchmarks/le10.html" ..I am really confused about the boundary conditions and tried my level best to compute it but ...
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### The etymology of “Umbrella Sampling”

I am just wondering where the term Umbrella Sampling came from. Is there another meaning of literal "umbrella" in physics or mathematics?
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### How to apply periodic boundary conditions to a Raviart-Thomas finite element space in Fenics? [closed]

I'm trying to use periodic boundary conditions within a Raviart-Thomas finite element space in Fenics (dolfin 1.2.0) in a Ubuntu 12.04 (amd64) machine (with python 2.7). If other FE space is used, ...
595 views

### Conservative finite-difference expression for the advection equation

Following on from the earlier question I am trying to derive a finite-difference scheme for the advection equation which is conservative. It was suggested that for advection equation with variable ...