How to convert the X & Y value in a matrix format?

Question

Asyran Abdullah 2018-9-26

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评论： Asyran Abdullah 2018-9-26

Hi, Given X and Y as follow:

area_length = 100;
area_width = area_length ;
x = round((area_length - 1) * (rand - 0) / (1 - 0) + 1); 
y = round((area_width - 1) * (rand - 0) / (1 - 0) + 1);

How to convert the X & Y value into matrix format? Because i want to add a weights for make i possible to perform a shortest path.

x= ;
y= ;
weights = rand ;%-ok
G = graph(x,y,weights); 
plot(G,'EdgeLabel',G.Edges.Weight);

Thanks for your help

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KSSV 2018-9-26

YOu need to have those points to get the shortest path........do you have those points?

Asyran Abdullah 2018-9-26

在 MATLAB Online 中打开

Yes, this is the point:

x = round((area_length - 1) * (rand - 0) / (1 - 0) + 1); 
y = round((area_width - 1) * (rand - 0) / (1 - 0) + 1);

x&y show the coordinate of each nodes, and the value will repeatedly change. However i don't know how to change the value into matrix in order to find a shortest path.

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Answer 1

Walter Roberson 2018-9-26

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编辑：Walter Roberson 2018-9-26

在 MATLAB Online 中打开

Your x and y calculated like the above define the coordinates of a single point. To do shortest path, you need multiple points.

I suggest,

N = 50;    %nodes
cutoff = 25;
area_length = 100;
area_width = area_length ;
x = round((area_length - 1) * (rand(N,1) - 0) / (1 - 0) + 1); 
y = round((area_width - 1) * (rand(N,1) - 0) / (1 - 0) + 1);   
A = squareform( pdist([x, y]) );
A(A > cutoff) = 0;
%and do any other tweaking for the A matrix
G = digraph(A);
plot(G, 'XData', x, 'YData', y);

and you can do shortest path calculations on G

With the above code, you could also use G = graph(A) to create undirected graphs, but if you do so then you would not be able to have asymmetric distance matrix. In the real world, there are cases where the transmit and receive path might not be the same.

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Asyran Abdullah 2018-9-26

在 MATLAB Online 中打开

Thanks Sir, it works!

N =  45;    %nodes
cutoff = 25;
area_length = 100;
area_width = area_length ;
x = round((area_length - 1) * (rand(N,1) - 0) / (1 - 0) + 1); 
y = round((area_width - 1) * (rand(N,1) - 0) / (1 - 0) + 1);   
A = squareform( pdist([x, y]) );
A(A > cutoff) = 0;
%and do any other tweaking for the A matrix
G =  graph(A ); 
G.Edges.W3 = randi(10, numedges(G) , 1); %laluan
G.Edges.Weight = G.Edges.W3; %weight
h = plot(G, 'XData', x, 'YData', y, 'EdgeLabel',G.Edges.Weight);
axis square;  
grid on 
G = rmedge(G, 1:numnodes(G), 1:numnodes(G)); 
 title('Finding Shortest Path on Random Node'); 
 path = shortestpath(G,1,45);
 highlight(h,path,'NodeColor','g','EdgeColor','g')