46 lines
1.8 KiB
Plaintext
46 lines
1.8 KiB
Plaintext
From: hinsen at cnrs-orleans.fr (Konrad Hinsen)
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Date: 09 Apr 1999 20:10:52 +0200
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Subject: Numeric: vector operations?
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References: <joe-090419991023459248@chinacat.salk.edu>
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Message-ID: <m34smpu0k3.fsf@chinon.cnrs-orleans.fr>
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Content-Length: 1517
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X-UID: 385
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Joe Strout <joe at strout.net> writes:
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> Playing with Numeric today, I noticed an apparent lack of common vector
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> operations, like normalization, vector-length, and cross product.
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If you mean vectors as in 3D geometry, look at the module Vector in my
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collection of scientific modules
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(http://starship.python.net/crew/hinsen/scientific.html).
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For vectors in the sense of rank-one arrays, I am not aware of any
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available module that contains these operations (and the cross product
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is limited to 3D-space anyway), but they are also much less frequently
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needed for non-geometric work.
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> These are fairly easy to code for my own evil purposes, but it's
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> surprising that they're not in there. Am I missing something? Or are
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> they purposefully omitted for some reason (e.g., they only apply to
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> very restricted sorts of matrices whereas other operations are more
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> general)?
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I guess there is too little advantage in writing
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Numeric.vector_length(v)
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over
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Numeric.sqrt(Numeric.add.reduce(v**2))
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--
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-------------------------------------------------------------------------------
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Konrad Hinsen | E-Mail: hinsen at cnrs-orleans.fr
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Centre de Biophysique Moleculaire (CNRS) | Tel.: +33-2.38.25.55.69
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Rue Charles Sadron | Fax: +33-2.38.63.15.17
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45071 Orleans Cedex 2 | Deutsch/Esperanto/English/
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France | Nederlands/Francais
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