CODEWITHSUNDEEP
matlabmatrixcomparison
user10790707
user10790707

Reputation: 33

MATLAB ismembertol compare 2 matrices by any row

Lets say I've two matrices A and x:

A=[10,10;
   20,20;
   30,30;
   NaN,NaN
   NaN,NaN];
x=[10,9;
   32,25;
   19,21;
   11,10;
   NaN,NaN];

I want to compare both matrices and find rows of x that correspond to any row of A within a certain tolerance of +-0.01 (=+-10%). So in this case:

Row 1 of x matches a row (row 1) in A that is within the tolerance.

Row 2 of x nearly matches a row (row 2) in A, but it is outside of +- 10%.

Row 3 of x matches a row (row 2) in A that is within the tolerance.

Row 4 of x matches a row (row 1 again) in A within the tolerance.

Row 5 of x can be ignored (only NaN).

It is guaranteed that A and x have the same size and number of elements. However, the rows are not in order, so I can't compare row-by-row. I just want to know if a row in x matches ANY row in A and if so, I'd like to save the index of that row. So in my case I'd prefer to have an output (logical) vector like:

v=[1,0,1,1,0]; % Logical vector with matching rows of x
id=find(v==1); % Result is [1,3,4], finds the indices

I tried various combinations of

ismembertol(A,x,0.1) % and ismembertol(A,x,0.1,'ByRows',true)

by using 'find', 'any', 'all' but I can't figure out the solution.

Upvotes: 1

Views: 593

Answers (1)

Luis Mendo
Luis Mendo

Reputation: 112659

You can use ismembertol with the 'ByRows' option:

result = ismembertol(x, A, 0.1, 'ByRows', true);

Note that:

  • NaN values cause a row to not match any other row.
  • As per the documentation, tol is interpreted as a fraction of tol*max(abs([A(:); x(:)])).

Upvotes: 1

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