Rank: 1341 based on 103 downloads (last 30 days) and 3 files submitted
photo

Shawn Walker

E-mail
Company/University
Louisiana State University
Lat/Long
40.72967529296875, -73.99526214599609

Personal Profile:

Assistant Professor in the Mathematics Department and Center for Computation and Technology (CCT)

Professional Interests:
Finite Element Methods, Free Boundary Problems, PDE-constrained Optimization, Shape Optimization

 

Watch this Author's files

 

Files Posted by Shawn View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
10 Jun 2014 Screenshot FELICITY Finite ELement Implementation and Computational Interface Tool for You Author: Shawn Walker mathematics, finite element method, modeling, simulation, computational enginee... 47 7
  • 5.0
5.0 | 3 ratings
13 Jan 2014 Screenshot MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker nearest neighbor sear..., quadtree, c class wrapper 29 5
  • 5.0
5.0 | 1 rating
22 Sep 2011 Screenshot Hamilton-Jacobi solver on unstructured triangular grids Solves a class of static HJB equations on general triangular grids. Author: Shawn Walker mathematics, physics, distance function, hamilton jacobi, level set, pde 27 0
Comments and Ratings by Shawn View all
Updated File Comments Rating
04 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker

OK. You want neighbors of a quadtree *cell*, such as the left neighbor of a quadtree cell, correct?

I have not interfaced this with MATLAB. However, please look at the source file:

'quadtree.cc'

and search for the class method:

'Locate_Left_Neighbor'

That is how you could do it from within C++. Interfacing it to MATLAB requires modifying 'mexQuadtree.cpp' and the corresponding MATLAB class.

I could expand the interface, but I cannot guarantee when that would happen. If you could give a few more details about what you want, that would be great.

For example, I assume you would want the UP, DOWN, LEFT, and RIGHT neighbors? The corner neighbors too?

03 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker

Shir,

Yes! Look at the m-file:

'test_Quadtree_Random_Points.m'

in the 'Unit_Test' sub-directory. It does a demonstration of k-nearest neighbor find.

Also, if you have added 'QuadTree' to your MATLAB path, then you can type:

help mexQuadtree
help mexQuadtree.kNN_Search

to get more info about how to use it.

08 Jan 2014 Example MATLAB class wrapper for a C++ class An example of how to safely encapsulate a C++ class in a MATLAB class, via a mex interface. Author: Oliver Woodford

I have a question about class_handle.hpp:

Regarding this line:

#define CLASS_HANDLE_SIGNATURE 0xFF00F0A5

What is so special about that number? Could I make up anything, as long as it is consistent in the C++ code?

The reason I ask is if I have two separate C++ classes that are mex-ed and interfaced using your approach. It seems I should use a different signature for each C++ class, for safety's sake. Is this true?

06 Jan 2014 Example MATLAB class wrapper for a C++ class An example of how to safely encapsulate a C++ class in a MATLAB class, via a mex interface. Author: Oliver Woodford

This is a great submission.

However, one minor comment. This code is taken from your class_interface_mex.cpp file:

if (!strcmp("train", cmd)) {
// Check parameters
if (nlhs < 0 || nrhs < 2)
mexErrMsgTxt("Train: Unexpected arguments.");
// Call the method
dummy_instance->train();
return;

Shouldn't it be:

if (nlhs > 0 || nrhs > 2)

because your "train" method does not need any inputs or outputs?

20 Sep 2012 inpolyhedron - are points inside a triangulated volume? Test if 3d points are inside a mesh. Or, voxelise a mask from a surface. Mesh can be non-convex too! Author: Sven

Awesome utility. I needed this!

Note to users: if it doesn't look like it is working, you may have to flip the normals of the faces. See help file.

Comments and Ratings on Shawn's Files View all
Updated File Comment by Comments Rating
04 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker shir

yes i need all kinds of neighbors except corner ones. It would be great if you'll do it. I will take a look at files myself too.

04 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker Walker, Shawn

OK. You want neighbors of a quadtree *cell*, such as the left neighbor of a quadtree cell, correct?

I have not interfaced this with MATLAB. However, please look at the source file:

'quadtree.cc'

and search for the class method:

'Locate_Left_Neighbor'

That is how you could do it from within C++. Interfacing it to MATLAB requires modifying 'mexQuadtree.cpp' and the corresponding MATLAB class.

I could expand the interface, but I cannot guarantee when that would happen. If you could give a few more details about what you want, that would be great.

For example, I assume you would want the UP, DOWN, LEFT, and RIGHT neighbors? The corner neighbors too?

04 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker shir

yes, i've seen it. I'm talking about neighbors of particular point which belongs to quadtree(node), not arbitrary points.

03 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker Walker, Shawn

Shir,

Yes! Look at the m-file:

'test_Quadtree_Random_Points.m'

in the 'Unit_Test' sub-directory. It does a demonstration of k-nearest neighbor find.

Also, if you have added 'QuadTree' to your MATLAB path, then you can type:

help mexQuadtree
help mexQuadtree.kNN_Search

to get more info about how to use it.

03 Feb 2014 MATLAB class wrapper for a C++ implementation of a Quadtree Efficient implementation of a point-region (PR) quadtree for fast nearest neighbor searches. Author: Shawn Walker shir

Hello, is there a function of neighbor search in your implementation ?

Contact us