Question

I am trying to find max value of a struct but max([tracks(:).matrix]) does not work. It gives me the following error: “Error using horzcat
CAT arguments dimensions are not consistent.” Do you have an idea?

Here is what my struct looks like:

tracks = 

1x110470 struct array with fields:
    nPoints
    matrix

tracks.matrix includes 3D points. For example here is

tracks(1,2).matrix:

33.727467   96.522331   27.964357
31.765503   95.983849   28.984663
30.677082   95.989578   29

Answer 1

You can use array fun, followed by another max to do this:

s.x = [1 3 4];
s(2).x = [9 8];
s(3).x = [1];

maxVals = arrayfun(@(struct)max(struct.x(:)),s);

maxMaxVals = max(maxVals(:));

Or, if you want to retain the size of .x after MAX:

s.x = [1 3 4];
s(2).x = [9 8 3];
s(3).x = [1 2 2; 3 2 3];

maxVals = arrayfun(@(struct)max(struct.x,[],1),s,'uniformoutput',false);

maxMaxVals = max(cat(1,maxVals{:}))

Or, if you know everything is n x 3

s.x = [1 3 4];
s(2).x = [9 8 3];
s(3).x = [1 2 2; 3 2 3];
matrix = cat(1,s.x)
maxVals = max(matrix)