Hi Tobias,
this sounds amazing. I'm looking forward to adapt our KNIME related code
to the new ops/ROIs. See below for some comments on the problems you
mentioned.
Am 05/07/2013 03:26 PM, schrieb Tobias Pietzsch:
Problems
========
Performance:
We have seen that we now are at nesting levels where the JIT becomes quite
unpredictable. So performance tuning for this stuff is not easy. In Madison,
Johannes showed that for special cases we can become very fast using javassist
to basically compile it ourselves.
This is really important for us. We should think about optimizing
the iteration over special ROIs like 0-1-planes in a n-dimensional
image, as we already started in Octobre
(https://github.com/imagej/imglib/tree/subinterval-cursor).
Temporaries:
One problem that is completely unsolved in this proposal is the creation of
temporary results (pixels, images, etc...). I had discussions with Christian
Dietz about this, because they really need this in KNIME. I mainly remember,
that there are all kinds of problems and we couldn't come up with a satisfying
solution. Christian, maybe you can comment a bit, on what the requirements for
temporary creation are.
If you concatenate operations, you are often not interested in the
intermediate results. For example if you do n-iterations of a
morphological erode, you really just need to know the final output.
If you process tons of images, one may want to avoid creating an output
(e.g. a temporary image) for each of the intermediate results, as in
many cases one temporary image is sufficient.
So the requirements would be, that if you concatenate ops, some
OperationBuilder is capable to reduce the amount of created temporary
images. Ideally, the OperationBuilder would also recognize, that e.g. a
Img<FloatType> could be used as a Img<BitType> temporary image.
Copying Ops:
For parallelization it is necessary that we copy Ops (which can be rather
complicated nested trees) in order to run on partitions of the input data in
parallel. This is not trivial, because the copying mechanism has to decide
which temporaries to recreate, reassign ports between copied ops, etc...
This is also crucial for us. As we already run the current ops in
parallel on partitions of the input data.
Two more questions: Are there plans to merge your
implementations/concept of ROIs with the work of Lee? What about
Labelings in ImgLib2 and ImageJ2, did you talk about them?
Best regards,
Christian
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