# [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?
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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
C.P. 6128, succ. A | Deutsch/Esperanto/English/Nederlands/
Montreal (QC) H3C 3J7 | Francais (phase experimentale)
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