[PYTHON MATRIX-SIG] linear algebra
Konrad HINSEN
hinsenk@ere.umontreal.ca
Mon, 19 Aug 1996 12:42:04 -0400
> All of the current interface routines (from LinAlg.py) do the following:
>
> return transpose(lapackfunction(transpose(input_matrix)))
>
> Should these two transpositions be there? This is obviously related to
> the different index order between NumPy and FORTRAN. Still, I've always
> personally considered it a superficial difference that is best ignored.
>
> If I remember by Linear Algebra correctly
> transpose(inverse(transpose(m))) == inverse(m).
True for inversion, but for little else, except in the special case of
symmetric matrices.
Personally I think it is important to work with the "right" index
order that everyone is used to. Python users should not have to know
anything about implementation details.
Besides, if I understand everything correctly, transposition should
cost almost nothing, right?
Konrad.
-------------------------------------------------------------------------------
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. Centre-Ville | Deutsch/Esperanto/English/Nederlands/
Montreal (QC) H3C 3J7 | Francais (phase experimentale)
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