NameError function not found

[Jean-Michel Pichavant]

Cameron Pulsford wrote:
> Hey everyone, I am extremely stumped on this. I have 2 functions..
>
> def _determinant(m):
>    return m[0][0] * m[1][1] - m[1][0] * m[0][1]
>
> def cofactor(self):
>    """Returns the cofactor of a matrix."""
>    newmatrix = []
>    for i, minor in enumerate(self.minors()):
>        newmatrix.append(_determinant(minor.matrix) * ((i%2) * -1))
>    return newmatrix
>
> And I get the following error when I try to run a.cofactor()...
>
> "NameError: global name '_determinant' is not defined"
>
> When I put the _determinant function nested within the cofactor 
> function it works fine. Normally I would do this, but a lot of other 
> methods use the _determinant method. They are both in the same class, 
> and they are at the same level, they are even in that order so I know 
> it should be  able to see it. I have a lot of functions that call 
> other functions in this class and everything is fine. [Also for the 
> picky, I know my cofactor method isn't mathematically correct yet ;-) 
> ] Am I missing something obvious here? Also if it helps the rest of 
> the code is 
> herehttp://github.com/dlocpuwons/pymath/blob/d1997329e4473f8f6b5c7f11635dbd719d4a14fa/matrix.py though 
> it is not the latest.

Maybe someone has already answered...

Looks like cofactor is in a class, so I'm assuming _determinant is in 
that class as well.

3 solutions:
- declare _determinant outside of the class, making it a private module 
function
- declare _determinant as method of the instance : def _determinant(self)
- if you want to keep _determinant as part of your class, it's up to you 
but you have to declare it as staticmethod (goolge it for details)

For isntance :
class MyClass
  def _determant()m:
     ...
  _determant = staticmethod(_determinant)

  def cofactor(self):
      ...
      x = MyClass._determinant(y) # this is how you call static Class 
method, but rarely these methods are set private (_ prefix)


Jean-Michel