[Octave-bug-tracker] [bug #46004] ezplot fails to recognise functions with 2 arguments passed as handles

[Tasos Papastylianou]

URL:
  <http://savannah.gnu.org/bugs/?46004>

                 Summary: ezplot fails to recognise functions with 2 arguments
passed as handles
                 Project: GNU Octave
            Submitted by: tpapastylianou
            Submitted on: Sun 20 Sep 2015 00:07:16 GMT
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Tasos Papastylianou <tpapastylianou>
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.0.0
        Operating System: Any

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Details:

To replicate:

Create a function f.m

%% in file f.m
function Out = f(a,b)
  if nargin < 2; b = 5; end
  Out = a-b;
end


Then at the terminal, compare:

ezplot(@f,[0,10,0,10]);


with:

ezplot(@(a,b) a-b, [0,10,0,10]);


The results should be the same, but they're not. Octave treats the function as
a single argument function.
(The two commands give the same output in Matlab as expected)

The error lies in line 135 of private function __ezplot__.m, which is called
by ezplot.m
This assumes erroneously that if the function handle passed in is not an
anonymous function, then it must necessarily come from a function with a
single argument; clearly this neglects functions with two arguments which are
also valid input for ezplot.

Suggested fix:
Add the following line below line 135:

if evalin('base',['nargin(''' func2str(fun) ''')']) == 2; args{2} = "y"; end


Many thanks,
T.




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