cygwin packaging approach for atlas3.6 and lapack3

Igor Pechtchanski
Sun Jun 26 05:37:00 GMT 2005

On Sat, 25 Jun 2005, James R. Phillips wrote:

> [snip]
> be replaced if possible by a tuned
> blas implementation optimized for the machine lapack runs on.
> atlas is capable of providing that optimized implementation; however, it
> needs to be compiled from source on the machine in which it will run in
> order to be most effective.  It would be possible to provide different
> binary packages for different processor architectures (Debian does
> this), however; this probably is a more complex project than I can
> handle at this point.

Why not include a postinstall script for atlas that would compile and
install the executables?

> ...So if atlas is built, it needs to replace both lapack and blas
> libraries.  There isn't a clean split between the libraries provided.
> See [1]. The libraries would be implemented as dll's, not as static
> libraries.

Would it be possible to build a helper DLL that would look for and load
the atlas DLLs dynamically?  That way, you don't have to replace existing
DLLs (always a shaky proposition).

> I am soliciting comments and suggestions on the approach I have outlined
> here. At a minimum, I'd like to know whether the core maintainers would
> in principle be willing to approve a package built in this way, i.e.
> with a default binary configuration which could be replaced with an
> optimized configuration if the source package is installed.

The problem with your approach is that if you install both the binary and
the source packages, and then upgrade the binary package, the optimized
versions will be gone.  I'd prefer the postinstall solution, combined with
a helper DLL that delegates to either the default or the optimized DLLs.
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