It is certainly possible to copy atlas libs from one machine to another
(and it is what you do when you install sage binaries, or when you install atlas in a linux distribution (debian, ubuntu with binary packages), and this will change nothing if both machines have the same processor. But it is quite sure that the machines will have different processors and different cache size: thus performances will not be optimal. The installation of atlas consist in compilation plus determination of optimal block sizes for matrix.matrix and matrix.vector products, by a set of tests. This is very efficient (on my 3.1 GHZ machine, the product of 2 matrix(RDF,1000) takes 0.2 second: this is 5 Gigaflops!).
yours
t.

Le 19/04/2010 07:24, William Stein a écrit :
On Sun, Apr 18, 2010 at 10:08 PM, John H Palmieri
<jhpalmier...@gmail.com>  wrote:


On Apr 18, 2:55 pm, William Stein<wst...@gmail.com>  wrote:
On Sun, Apr 18, 2010 at 2:50 PM, John H Palmieri<jhpalmier...@gmail.com>  wrote:

If I've built atlas once on a particular machine and if it took a long
time (e.g. t2.math, but also on various linux boxes), if I want to
build Sage again from scratch, are there just some files I can copy so
I can just touch spkg/installed/atlas... to skip it the next time?

Yes, just do:

            1. touch spkg/installed/atlas??
            2. cp the following files to local/lib: libatlas.*
libcblas.* libf77blas* liblapack*

I'm guessing I also need local/include/atlas/* and the files cblas.h
and clapack.h from local/include.  Is that right?

I didn't in my testing, but it certainly couldn't hurt.


It would be great if you could add this to the README.txt for Sage...

If I have the time and if I can figure out a good place to put it,
I'll do it.

--
John


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