[Numpy-discussion] how does numpy handle views and garbage collection?

Chris Colbert sccolbert@gmail....
Wed Sep 30 06:43:05 CDT 2009


Lets say I have function that applies a homogeneous transformation
matrix to an Nx3 array of points using np.dot.

since the matrix is 4x4 I have to add a 4 column of ones to the array
so the function looks something like this:

def foo():
     <--snip-->
     pts = np.column_stack((Xquad, Yquad, Zquad, np.ones(Zquad.shape)))

     transpts = np.dot(transmat, pts.T).T

     return transpts[:,:3]

Since i'm returning just the view of the array, I imagine python
doesnt garbage collect transpts once the function returns and falls
out of scope (because numpy has increfed it in the view operation?).

So in essence, I still have that whole column of ones hanging around
wasting memory, is that about right?

Cheers,

Chris


More information about the NumPy-Discussion mailing list