What test is validateattributes() using to check for attributes 'positive' or 'nonnegative' ? (possible bug)

Suppose a class MyClass with overloaded operators for comparison with numeric values. In other words, I can call

obj = MyClass();
obj > 0; obj >= 0; obj < 0; obj <=0;

and get appropriate results. However, the calls

validateattributes(obj,{'MyClass'},{'positive'})
validateattributes(obj,{'MyClass'},{'nonnegative'})

always fail. Is this a bug, or is validateattributes using something other than gt, ge, lt, le calls?

Thanks, -naor (R2014b)

Answer 1

[Geoff Hayes]

Naor - for MATLAB R2014a (on OS X 10.9.5) in order for

 validateattributes(obj,{'MyClass'},{'positive'})

to pass, you need the following anonymous function to resolve to true

 @(x)(isnumeric(x)||islogical(x))&&isreal(x)&&~any(x(:)<=0)

where x is the instance of your MyClass. I suspect that all you are missing is the isreal overload as you should have the isnumeric and le already. For

 validateattributes(obj,{'MyClass'},{'nonnegative'})

you need the following anonymous function to resolve to true

 @(x)(isnumeric(x)||islogical(x))&&isreal(x)&&~any(x(:)<0)

with the only other function that you need to overload being the lt one.

[Naor Movshovitz]

Thanks Geoff - it was indeed the missing isreal.