using attribute 'size' in validateattributes

Hi,Any idea how I can pass size of a matrix to validateattributes? I need to check that size(A,2) < 2, where A is the input to my function.

Would be appreciated.

Answer 1

[David Young]

I'm pretty sure validateattributes can't do what you want.

If in fact A is required to be a column vector, you can use

validateattributes(A, {'numeric'}, {'column'});    % change class as appropriate

but if it's OK for A to be empty, or if it's possible for A to have 3 or more dimensions, then you need to write out the check in the conventional way:

if size(A,2) >= 2
  error(...);
end

If you are using writing a checking function for inputParser, the answer is that it's possible to do what you want but a little more complex - please say if you need that.

[Adam]

Or if emptiness is the only other option you want to accept in addition to a column I tend to use:

if ~isempty( A )
   validateattributes(A, {'numeric'}, {'column'});    % change class as appropriate
end

[Sina Shojaei]

Thanks

Answer 2

[Daniel Lyddy]

I think this might be what you want:

% set up validator
myValidMatrix = @(x) validateattributes(x, {'numeric'}, ...
{'real', '2d', 'size', [nan, 2]});

That nan in the 'size' vector is an "I don't care". If instead your array is 3D and you only care about the middle dimension, you would do:

myValidArray = @(x) validateattributes(x, {'numeric'}, ...
{'real', '3d', 'size', [nan, 2, nan]});

~Daniel