Error - ??? Improper assignment with rectangular empty matrix - using "for"

Hello,

I am attempting to run a script through several loops. However I keep receiving an error message no matter what I do to try and fix it. Please see below:

A=[1 3 4 2 5];

B=[1 2 3 4 5];

n=length(A);

Ind=ones(1,n);

for i=1:n

    Ind(i)=find(A<=min(B));
    A(Ind(i))=Inf;

end

Ind

Essentially I want to fill in the array "Ind" with the indices relating A and B. If successful the output from this particular code should be Ind=[1 4 2 3 5]. Unfortunately this error keeps appearing no matter what I try "??? Improper assignment with rectangular empty matrix." I would appreciate any assistance you could provide.

Thanks!

[Oleg Komarov]

Not clear what you want, what are you actually trying to do?

Answer 1

[Matt Tearle]

You can also use MATLAB set functions, under certain assumptions. In particular, if you expect both A & B to have exactly the same elements (but B is a permutation of A), then this will do the job:

if isempty(setdiff(A,B))
  [~,Ind] = intersect(A,B)
else
  error('A & B have different elements')
end

[Daniel]

How would this work for arrays with multiple rows?

[Matt Tearle]

How do you mean, exactly? A and B both have n rows and you want to do this row-by-row? Or each row of A against every row of B?

Answer 2

[Robert Cumming]

Have you tried stepping through your code in debug mode?

Objective: You want to find where each B is located in A - correct?

So for each B (not the min) find where it is in A, i.e.

find(A==B(i));

You should do checks to make sure you dont have duplicates (As that will fail in the above case)