Re: Matrix

From: Jerome Lecomte (jlecomte_at_[hidden])
Date: 2001-03-13 08:37:32

Walter wrote:

> I currently see the following points to discuss when developing a
> matrix library:
>
> - support for mathematical notation
I agree this is the whole point (and maybe the only reason) to have a C++
interface.

> - efficiency
That's where I don't quiet follow. Isn't the best way to achieve Fortran
speed, to call Fortran ??? I don't see the point in pushing further the
expression template trend ... This is a nice concept, and something to
develop for the future (when compilers better support export keyword) but
right now, I would support something along the line of lapack++ (commercial
by RogueWave) where the C++ is actually just an interface to Fortran code.

> - functionality
> We restricted our interest to support BLAS like functionality. But
> who knows, what else one can do with matrices and vectors...
B in BLAS stands for basic :-) Thus there is definitely more to linear
algebra than Blas. In particular Lapack is built on top of Blas and
implements a ton of non-trivial routines, that alone justify a Fortran
interface. The only problem of Fortran as far as I am concerned is the
interface, wrapping it in C++ is just what I need.

> -compatibility
> This is an interesting question: should a boost matrix library run
> under MSVC for example?
I wish so.

Some might wonder : what if I don't have access to a fortran compiler ? Good
question. There are 3 answers: 1. gcc is can compile fortran effectively and
generates compatible .o 2. There is a tool called f2c that compiles fortran
with a c compiler (that would be a last resort solution). 3. Intel
distributes a product called MKL (matrix kernel library) that includes a
prebuilt BLAS implementation (BLAS by the way is a standard that happen to
have Fortran calling convention for historical reasons but one could write
BLAS in C).

As far as boost is concerned, we could distribute the wrapper as part of
boost. I can understand though that it isn't nice to distribute an
half-finished product and request the user to download additional material
to make it work ...

my $.02

Jerome

 
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