Re: an unreported fix to union.m

[Juan Pablo Carbajal]

On Fri, Jul 31, 2015 at 1:02 PM, Juan Pablo Carbajal
<address@hidden> wrote:
> Hi,
>
> The developer of this software (see commments)
> http://journal.frontiersin.org/article/10.3389/fninf.2013.00008/abstract
>
> fixed an compatibility issue in union.m of octave. Of course the fix
> is not compatible with Octave standards. However if we need this fix I
> will port it.
>
> The difference is
>
> --- /home/juanpi/Devel/octave/default/scripts/set/union.m
> +++ /home/juanpi/Downloads/ndt.1.0.4_exported/octave_code/union.m
> @@ -40,7 +40,7 @@
>  ## @seealso{unique, intersect, setdiff, setxor, ismember}
>  ## @end deftypefn
>
> -## Author: jwe
> +## Author: jwe, modified by Ethan Meyers 2015
>
>  function [y, ia, ib] = union (a, b, varargin)
>
> @@ -48,11 +48,35 @@
>      print_usage ();
>    endif
>
> -  [a, b] = validsetargs ("union", a, b, varargin{:});
> +
>
>    by_rows = nargin == 3;
>    isrowvec = isvector (a) && isvector (b) && isrow (a) && isrow (b);
>
> +
> +  % Modified by Ethan to deal with creating a union between an empty
> vector and a cell array
> +  if isempty(a)
> +    if by_rows
> +      y = unique(b, 'rows');
> +    else
> +      y = unique(b);
> +    end
> +    return
> +  end
> +
> + if isempty(b)
> +    if by_rows
> +      y = unique(a, 'rows');
> +    else
> +      y = unique(a);
> +    end
> +    return
> + end
> +
> +
> + [a, b] = validsetargs ("union", a, b, varargin{:});
> +
> +
>    if (by_rows)
>      y = [a; b];
>    else
>
>
> Comments?

I have condensed the changes into a single line correction and added
some tests. Please verify that indeed the output is compatible with
Matlab's

https://savannah.gnu.org/patch/index.php?8710