2012/3/1 Stéfan van der Walt
<stefan@sun.ac.za>
Hi Nadav
On Wed, Feb 29, 2012 at 9:36 PM, Nadav Horesh <
nadavh.horesh@gmail.com> wrote:
> I am working on a simple frame work as a replacement for
> ndimage.genereic_filter and numeric's neighbourhood iterator (I hope it
> would be faster and easier to use).
the one you are writing). I'd like to provide multiple
implementations of some commonly used functions (convolution, e.g.),
so that we can have a performance based series of fallbacks, such as
GPU -> Cython -> Python. That way, algorithms can be run on any
system, but will execute most rapidly on those supporting, say,
OpenCL. Another advantage is that if, in the future, we write an even
faster implementation, the benefit is immediately available to the
user, without rewriting any code.
Stéfan
From the looks of the implementation, it seems none of the current modules would need to be changed unless a backend was added. And even then, it looks simple to modify an existing function to add a backend. Does this sum it up:
* Add `@add_backends` to function with new (optional) backend
* register backend function using `backend.register` in the `__init__` file for the function
* Subclass tests from `BackendTester` (an additional decorator for test functions might be good, if possible)
The rest of the changes would happen in separate files for each function implementation. If this is an accurate description, then I think the backend system would be a good addition and wouldn't really add any annoying boilerplate code.
Stefan: Do you have an idea of what needs to be done to get this merged? After a quick look: 1) It needs to be moved from the scikits.image namespace to skimage, 2) there are questionable changes to "filter/edges.py" and "filter/tests/test_edges.py" in the PR, 3) implementation should be moved from "backend/__init__.py" to something like "backend/core.py" (or I guess we've been using the convention "backend/_backend.py").
Also, I'm not crazy about dumping backend functions into a "backend" subdirectory for each module. Maybe they should go in a backend-specific subdirectory. So, for example, "filter/backend/edges_opencl.py" would move to "filter/opencl/edges.py".
-Tony