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Re: Non square matrix transpose?


E. Robert Tisdale writes:
 > Are you sure that there is no other missing functionality?  Or do
 > you mean you to just keep tacking functions onto the library as
 > people ask for them?

The library is under development (version 0.x), so more functions will
be added/removed/redesigned in the future. 

When we get to version 1.0 the API will be frozen (one of the criteria
for the 1.0 release is that we are happy with the API). Any changes in
the 1.x series will be backwards compatible.

Of course, we might also start a 2.x version based on lessions learned
from 1.0, and that would not have to be backwards compatible.

Like most free software projects there is no a priori specification of
the complete system -- just a goal to work towards and some
guidelines/conventions for getting there.

 >  It strikes me as just a bit inefficient to make a copy of a matrix
 > just so that you can reference the elements in a different order.
 > And, as I recall, the BLAS library will operate just as happily on
 > the transpose view of a matrix as upon the matrix itself.

For BLAS operations one should certainly use the transpose argument
and not physically transpose the matrix.  In other applications it may
be necessary to rearrange the elements though.

 >  Why couldn't you just add a field of type CBLAS_TRANSPOSE_t to
 > your matrix struct which tells GSL library functions whether the
 > data array represents a matrix or it's transpose? 

Here we follow the existing NAG and IMSL matrix conventions, which are
based on a fixed ordering and don't generally use a transpose argument
(except in their own BLAS/LAPACK-type routines).

regards

Brian Gough

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