[Cython] c-array of numpy ndarrays?

[Dag Sverre Seljebotn]

Brian Blais wrote:
> Hello,
> 
> In my question for optimization of my routines, I am trying to pre-fill 
> a static c-array from a list of numpy ndarrays.  Previously, I did 
> something like:
> 
> cdef double *w[30]
> cdef int r[30],c[30]
> 
> and then I'd run through my list, and get the shape info and the data 
> pointer, and fill in these arrays.  This works, but then I have to do 
> all my 2D -> 1D indexing, like:
> 
> w[k][i+c[k]*j]
> 
> which is ugly, and prone to typos.  I'd like to do:

So the underlying problem here is that each array has a (widely 
different) size?

> cdef np.ndarray w[30]

No, it will be a long while before you can do this. Perhaps in a year 
one /might/ be able to use e.g. a C++ vector of buffers, but no promises.

You can always wrap the solution above into e.g. a cdef class, so that 
you can write

yourspecialarrayobject.get(k, i, j)

-- 
Dag Sverre