Hi Dave, hi all, I read with interest you plans for reviving MTL. It is certainly a shame that development of MTL was been stagnant for so long. It certainly had many interesting design features and I used it for all my work for many years. That said I switched to using and developing uBLAS long ago and it has an excellent design. On Saturday 05 June 2004 13:53, David Abrahams wrote:
"Neal D. Becker" <ndbecker2@verizon.net> writes:
David Abrahams wrote:
Tom Brinkman <reportbase@yahoo.com> writes:
In short, lets tell the world that this is the premiere place for advanced mathmatical library development, as I believe that it could be.
Comments?
1. I think oonumerics.org has the jump on us here, though the site seems to be douwn at this moment.
2. I will be starting work on a rewrite of MTL (the Matrix Template Library) for linear algebra soon.
What do you plan for MTL? How is it different than ublas?
MTL is aimed at linear algebra, whereas IIUC ublas is not.
There's a lot more to what's in the current plan than I can lay out here, but the focus will be on support for different kinds of matrices with combinations of these aspects
o Shape o Orientation o Symmetry o Sparsity o Blocking o Upper / Lower storage o Unit diagonal Other then the many forms of blocking (other then banded) uBLAS supports all
Well the L and A in uBLAS certainly stand for Linear Algebra! Of course the B stands for Basic and uBLAS's primary aim is to provide the standard set of BLAS functions in a modern C++ environment. Of course as it stands the complete uBLAS library is more then just the BLAS functions and includes some common Linear Algebra algorithms and many useful types. That said I think it is important to separate BLAS functions from domain specific linear algebra algorithm development. This is something that proved itself since the seventies. these in its design. This really is its strength! To a large extent they can even be combine these properties where it makes mathematical sense. For example you can wrap up one of a number of sparse matrix types in a symmetric adaptor.
and operations like:
o scalar-vector (vector-scalar) multiplication o vector addition (and subtraction) o apply linear operator (left) o norm o inner product o triangular solve
Other then 'apply linear operator' these are all in uBLAS!
with expression templates, and of course, zero abstraction penalty ;-) Of course uBLAS does this all with ET, but the abstraction penalty may not be zero :-)
Other then the lack of ET in the current MTL the big difference between the two libraries is the definition of iterators. Neither design seems to be perfect with regard to efficiency. Since uBLAS is already in Boost and has a well established and clean user syntax it would seem strange to ignore it. For the perspective of building further Linear Algebra algorithms it would not be too hard to use the syntax sufficiently portably so that a future MTL with expression templates could not be used interchangeably. Michael -- ___________________________________ Michael Stevens Systems Engineering Navigation Systems, Estimation and Bayesian Filtering http://bayesclasses.sf.net ___________________________________