# Undefined operator '-' for input arguments of type 'cell'.

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Amir Antonir on 1 Feb 2018
Commented: Star Strider on 1 Feb 2018
Hi all, I am try to subtract 2 matrices, stored in 2 separate cells, and store the result in a 3rd cell. See below:
ERR_C{1,1}=10^8*(sigT_C{1,1} - recapT_C{1,1});
The error : Undefined operator '-' for input arguments of type 'cell' keeps popping up.
Can someone please assist in rectifying ?

Star Strider on 1 Feb 2018
The reason it is not possible to do mathematical operations on cell arrays is that cell arrays can contain anything, including string and character data, and mathematical operations do not apply to data types such as those.
If ‘sigT_C{1,1}’ and ‘recapT_C{1,1}’ have the same internal dimensions (so you can do the subtraction), this turns out to be a two-step process:
sigT_C{1,1} = {rand(5)}; % Create Data
recapT_C{1,1} = {rand(5)}; % Create Data
ERR_C{1,1} = cellfun(@minus, sigT_C{1,1}, recapT_C{1,1}, 'UniformOutput',false);
ERR_C{1,1} = cellfun(@times, {1E+8}, ERR_C{1,1}, 'UniformOutput',false);
There are likely other ways to do this. I assume you want ‘ERR_C{1,1}’ to have the same essential structure that the argument cell arrays have, and this will produce that result.

Amir Antonir on 1 Feb 2018
Thank you Star Strider. Different dimensions was the issue.
Star Strider on 1 Feb 2018
As always, my pleasure.

A. Sawas on 1 Feb 2018
I would suggest that you make sure that the both sigT_C{1,1} and recapT_C{1,1} are matrices. You can try this code and check if you are still getting the same error:
A = sigT_C{1,1};
B = recapT_C{1,1};
ERR_C{1,1}=10^8*(A-B);

#### 1 Comment

Amir Antonir on 1 Feb 2018
thanks