Hi,

I would like to create an animation to demonstrate LDPC coding which is based on Sum-Product Algorithm

So far I have created a graph which shows the connections between symbol nodes (left) and parity nodes (right) and would like to animate points travelling from symbol to parity nodes and back.

The figure is drawn by executing the following method:

function drawVertices(H)
hold on;
nodesCount = size(H);
parityNodesCount = nodesCount(1);
symbolNodesCount = nodesCount(2);
symbolPoints = zeros(symbolNodesCount, 2);
symbolPoints(:, 1) = 0;
for i = 0 : symbolNodesCount - 1
    ji = symbolNodesCount - i;
    scatter(0, ji)
    symbolPoints(i + 1, 2) = ji;

end;
parityPoints = zeros(parityNodesCount, 2);
parityPoints(:, 1) = 10;
for i = 0 : parityNodesCount - 1
    ji = parityNodesCount - i;
    y0 = symbolNodesCount/2 - parityNodesCount/2;
    scatter(10, y0 + ji)
    parityPoints(i + 1, 2) = y0 + ji;
end;
axis([-1 11 -1 symbolNodesCount + 2]);
axis off

%connect vertices
d = size(H);
for i = 1 : d(1)
    for j = 1 : d(2)
        if(H(i, j) == 1)
            plot([parityPoints(i, 1) symbolPoints(j, 1)], [parityPoints(i, 2) symbolPoints(j, 2)]);
        end;
    end;
end;

So what I would like to do here is to add another method which takes start point (x and y) and end point as arguments and animates a travelling circle (dot) from start to end and back along the displayed lines.

I would appreciate if anyone of you could show the solution or suggest any useful tutorial about matlab simulations.

Thank you!