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Ho Robin. |
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|
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On Sunday 30 March 2003 02:47, Robin H. Johnson wrote: |
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[skipped] |
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> Python's implementation of a MAP (dictionary) implemented via hash |
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> tables, but I can't find anything on tweaking the load factor and |
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> initial capacity, which makes a significent difference on data sets of |
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> large but known sizes. |
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Then it looks like you might want to look here: |
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http://www.python.org/doc/current/lib/module-array.html |
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This is a more lightwieght implementation and provides a buffer interface. |
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|
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There are also numerical python modules: |
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http://numpy.sourceforge.net/numdoc/HTML/numdoc.htm |
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|
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However if you need to do large numerical computations and you worry about |
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efficiency, then I would say/agree that python is probably not the right |
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choice. I would pick C++/Pascal for the task (just as you intended). The code |
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can be hooked back to python without too much trouble (use swig for example). |
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So that you may implement crytical functions in say C++ and then call them |
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from your "main" python code. It is also possible to hook python code to C++, |
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the other way around. As I remember swig can help in that too.. (help mostly |
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means automating significant parts of the process). |
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|
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|
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> For these structures, various iterators are required as well, as this is |
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> the best way to traverse the data. Functional programming methods to |
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> apply to the data is also required, such as (Python provides these first |
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> three) filter, map, reduce, (Python doesn't seem to have these last |
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> three) set union, set difference, set intersection. |
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Yes, this is true for 2.2 series. Sets are not completely supported as you |
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just mentioned, only basic functionality. |
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|
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> It seems Python did at one stage consider adding SETS: |
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> http://www.python.org/peps/pep-0218.html |
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> But I can't make much sense of the outcome. |
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Well, its being added rather than was considering at one stage. I hope that |
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PEP paper makes more sense this way :). |
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From what I can see this functionality is already (at least partially) in |
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python-2.3, which is in alpha stage right now. So chances are quite good, |
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that this will appear in 2.3 when it's released (probably as experimental |
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feature as is common, though this may be done as a separate module, in which |
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case it will just be awailable). |
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|
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|
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> It seems I would have to implement BIMAP myself, since there isn't one |
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[skip] |
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> BIMAP is the main structure that I would be using, but SET and MAP also |
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> to a slightly lesser degree. I want to create a BIMAP containing the |
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> relative paths to each ebuild as one key, and the IUSE data from that |
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> ebuild as the other key. |
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Oh, I see. Yea, I don't remember seing bimap-type structures in built-in |
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types, though I would not consider myself a python guru in any way.. |
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Just trying to help here the best way I can :). |
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|
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You might want to try one of python mailing lists: |
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http://www.python.org/psa/MailingLists.html |
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There is one devoted to sets and another to numerical stuff as well as some |
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newsgroups. I think there is an irc channel on irc.freenode.net as well |
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(populated at around 100+ when I tried it some time ago), I think that was |
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#python. |
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Hope this makes any sense.. |
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|
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George |
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-- |
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