[PYTHON MATRIX-SIG] Are we talking about one thing or two?

Hinsen Konrad hinsenk@ere.umontreal.ca
Wed, 13 Sep 1995 13:43:37 -0400

   When we started talking about the use of operator* being elementwise or
   "mathematical", I thought that was the extent of it - a disagreement
   over one operator.  But now I think we may actually be asking for two
   completely different animals. Mr. Hugunin suggested that "matrix" is,
   in effect, just a name.  Well, maybe not.  For what we do here we have

But the one operator is the only difference - apart from the interpretation
of multiplication, "mathematical" matrices are just a special case
of general arrays.

   "mathematical" semantics described earlier.  The "elementwise" stuff is
   more like what we would call an "array" or "table" - although "tensor"
   sounds good to me.  

Not to me though. A tensor is a mathematical object representing a
physical quantity in space that exists indepently of a choice of a
coordinate system. A tensor is thus not just a table of numbers, but a
set of numbers with a well-defined transformation property when
changing from one coordinate system to another.

I vote for "array" as the name for what we are trying to do.

   Why?  For practical reasons.  We here - and I would submit that many
   other organizations are like this - do more Matlab-like work.  The way
   Matlab defines a matrix is not a problem but a huge advantage for us.

But in what way would a more general concept be a disadvantage?

Konrad Hinsen                     | E-Mail: hinsenk@ere.umontreal.ca
Departement de chimie             | Tel.: +1-514-343-6111 ext. 3953
Universite de Montreal            | Fax:  +1-514-343-7586
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