MATLAB: Calculate the (geometrical) distance between points of a matrix

distancegeometrymatrix position

Lets say I have a large matrix full of zeros, with a few numbers (1,2,3,4,5) located at various positions. Now I want to calculate the distances from point 1 to 2, 1 to 3, 1 to 4 and 1 to 5. Assuming that e.g. the width of the columns in this matrix is 0.4mm and the width of the rows is 0.25mm. Maybe there is already a code/toolbox out there to do such things?

Best Answer

eg:
data =[0     0     0     0     0     0     0     0     0     0
     0     0     0     0     3     0     0     0     0     0
     0     1     0     0     0     0     0     0     0     0
     0     0     0     2     0     0     0     0     0     0
     0     0     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0     0     0
     0     0     0     0     0     4     0     0     0     0
     0     0     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     5     0     0
     0     0     0     0     0     0     0     0     0     0]
[i1,j1,c] = find(data)
ijc = sortrows([i1,j1,c],3)
d = bsxfun(@minus,ijc(2:end,1:2),ijc(1,1:2))
out = hypot(d(:,1)*.25,d(:,2)*.4)
OR
use function dist from Neural Network Toolbox
c = dist(bsxfun(@times,ijc(:,1:2),[.25 .4]).');
out = c(:,1);
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