Negative array indicies and slice()
Andrew Robinson
andrew3 at r3dsolutions.com
Mon Oct 29 20:04:43 EDT 2012
On 10/29/2012 10:53 PM, Michael Torrie wrote:
> On 10/29/2012 01:34 PM, Andrew Robinson wrote:
>> No, I don't think it big and complicated. I do think it has timing
>> implications which are undesirable because of how *much* slices are used.
>> In an embedded target -- I have to optimize; and I will have to reject
>> certain parts of Python to make it fit and run fast enough to be useful.
> Since you can't port the full Python system to your embedded machine
> anyway, why not just port a subset of python and modify it to suit your
> needs right there in the C code. It would be a fork, yes,
You're exactly right; That's what I *know* I am faced with.
> Without a libc, an MMU on the CPU, and a kernel, it's not going to just compile and run.
I have libc. The MMU is a problem; but the compiler implements the
standard "C" math library; floats, though, instead of doubles. That's
the only problem -- there.
> What you want with slicing behavior changes has no
> place in the normal cPython implementation, for a lot of reasons. The
> main one is that it is already possible to implement what you are
> talking about in your own python class, which is a fine solution for a
> normal computer with memory and CPU power available.
If the tests I outlined in the previous post inaccurately describe a
major performance improvement and at least a modest code size reduction;
or will *often* introduce bugs -- I *AGREE* with you.
Otherwise, I don't. I don't think wasting extra CPU power is a good
thing -- Extra CPU power can always be used by something else....
I won't belabor the point further. I'd love to see a counter example to
the specific criteria I just provided to IAN -- it would end my quest;
and be a good reference to point others to.
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