[Matrix-SIG] Fibonnaci

[Charles G Waldman]

Yoon, Hoon (CICG - NY Program Trading) writes:
 > Hi, 
 > 
 >   Iam trying to do Fibonnaci numbers. Obviously I am trying to raise the
 > base matrix x to some power p, but I don't know how to do it in one step. I
 > would like to call something like x^34.

The problem is that the default __mul__ and __pow__ methods on arrays
multiply the arrays elementwise, rather than as a matrix multiply.
You could define an object with __mul__ and __pow__ methods (and their 
"r" versions) to behave as "proper" matrices.

However, you shouldn't have to do this because Numeric provides a
"Matrix" class which does exactly this.  I was about to send you an
example of its use, when I made the unpleasant discovery that it's
broken in the current distribution:

buffalo:numeric$ python Matrix.py
Traceback (innermost last):
  File "Matrix.py", line 27, in ?
    print m*m
  File "Matrix.py", line 12, in __mul__
    return self._rc(matrixmultiply(self.array, asarray(other)))
AttributeError: _rc
buffalo:numeric$ 

buffalo:numeric$ python UserArray.py
['_typecode', 'array', 'name', 'shape']
() (100, 100)
Traceback (innermost last):
  File "UserArray.py", line 95, in ?
    ua_small=ua[:3,:5]
AttributeError: __getitem__


I guess nobody's really been doing much with UserArray :-(

I'll see if I can cook up a quick patch for this....