Matrices and "type tags"

[Thomas Hoffmann]

In the recent talk about a "backsub" function the idea of automatically 
recognizing 
tridiagonal matrices surfaced.

If a matrix has not a special type "tridiagonal", then it has to have a "tag", 
which says 
that the matrix has this property (RLaB uses such "tags", matrices are lists 
there) or 
one has to check the matrix for this property (which takes a lot of time).

The state-of-the-art in Octave is, that we have complex and real matrix types 
recognized 
by the system and handled accordingly, but that we have to look for the other 
"special" 
properties of matrices ourselves (e.g. one can (wrongly) give a non-symmetric 
matrix to 
chol()).

This means, that if we have no type tags, we should use special functions for 
special 
cases instead of Octave having to look through the matrices for their 
properties.

On the other hand, this takes away some "elegancy" from the code.

Any opinions?

=============================================================================
Thomas Hoffmann, Institut fuer Halbleiter- und Mikrosystemtechnik, TU Dresden 
E-mail: address@hidden



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