Nick <nleio...@gmail.com> wrote:
> this is the new oop version, its pretty messy currently, and i do
> understand it is a simple routine, but i'm using it as an exercise to
> learn oop python...
>
> first the (current) traceback:
> [:~/python]$ python oop_covariance.py b2ar_all_test b2ar_all_test
> <Eigen.Eigen_vect instance at 0x7fa26c404ab8>
> <Eigen.Eigen_vect instance at 0x7fa26c404ab8>
> Traceback (most recent call last):
> File "oop_covariance.py", line 24, in <module>
> cov = set1.covariance(set2, Eigen_vect.dot)
> File "/home/nleioatts/python/Eigen.py", line 66, in covariance
> print self.vectors[i][i]
> AttributeError: Eigen_vect instance has no attribute '__getitem__'
You are trying to use your Eigen_vect class as an array. In order for
an object to act as an array it needs a __getitem__ method.
> class Eigen_vect:
> def __init__(self, e_val, e_vect):
> self.e_val = e_val
> self.e_vect = e_vect
> def length(self):
> return len(self.e_vect)
>
> def dot(self, other):
> d = 0.0
> if other.length() != self.length():
> raise ValueError, "Eigen Vectors not same Length"
> for k in range(self.length()):
> # print "HI NICK", self.e_vect[k], other.e_vect[k]
> d += float(self.e_vect[k]) * float(other.e_vect[k])
> return d
Either add a __getitem__ method like this
def __getitem__(self, n):
return self.e_vect[n]
Or you might want to subclass list if you are going to do a lot of
list like operations on Eigen_vects, eg
class Eigen_vect(list):
def __init__(self, e_val, e_vect):
self.e_val = e_val
self[:] = e_vect
def dot(self, other):
d = 0.0
if len(other) != len(self):
raise ValueError("Eigen Vectors not same Length")
for a, b in zip(self, other):
d += float(a) * float(b)
return d
Notice that now these things are lists, you can use len, zip etc on
them which makes the code much neater.
e = Eigen_vect(3, range(10))
f = Eigen_vect(4, range(1,11))
print e
print f
print e[2]
print e.dot(f)
Which prints
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
2
330.0
--
Nick Craig-Wood <n...@craig-wood.com> -- http://www.craig-wood.com/nick
--
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