Asked by Alessandro
on 31 Oct 2012

I'm using the pde toolbox to solve a certain elliptic equation in 2D.

Solution is fine, although I do need to plot it along a given line, i.e. to cut a planar slice from the 3D mesh representing the solution.

I can't figure out a way that smartly involves the toolbox functions.

Any help appreciated.

Answer by Bill Greene
on 2 Nov 2012

Accepted answer

Hi,

Here is one way to create such a plot. Assume you have the point matrix created by the PDE Toolbox mesher, p, and a solution vector, u. The function below will create a plot of that solution along a line defined by the x and y locations of the two end points. My example is for a solution on a unit square and I want a plot along the line (0,.5) to (1,.5). I want to include 25 points in the plot. As you can see, the real work is being done by the TriScatteredInterp function from core MATLAB.

plotAlongLine(p, u, [0,.5], [1,.5], 25);

function plotAlongLine(p, u, xy1, xy2, numpts) x = linspace(xy1(1),xy2(1),numpts); y = linspace(xy1(2),xy2(2),numpts); F = TriScatteredInterp(p(1,:)', p(2,:)', u); uxy = F(x,y); figure; plot(x, uxy); end

Bill

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