Lapack in Cygwin

[serlancelot]

Hi everybody
I eventually downloaded the cygwin program, to use the linux environment with Windows; I got to make it work (by the way thanks to Julien and everyone here who helped me), using a source code which calls subroutines from BLAS library downloaded as I installed Cygwin, instead of adding the code of the blas routines in queue to my code.
Now I need to try it with a routine from the Lapack library.

However I still have some questions, which I need to be answered, to let me have a wider complete comprehension.
Why was it so relatively simple? I mean I read the post of the other members, and I see that often they have alot of difficults and need to do alot of complicated things, like testing alot of routines and so on.. Why didn't I need to it too? Maybe because when you download cygwin does it come all in a way that you don't need to test anything? And beside it, which are the limitations of the package downloaded in this way, instead of in the other more complicated, but maybe more efficient way?
How different could it be if installed Lapack in any different way than that I did?
I'm using windows 98, with a PentiumII (everything quite old).
If I desired to advance, to improve the system, what should I do? I guess I should download the single package of lapack. But could I work on my non-unix-nor-linux-PC without reliing at Cygwin? How?

Thank for your patience
Marco

[serlancelot]

by the way, I forgot to say that I use cygwin to work with fortran g77, so while I was installing cygwin I dowloaded gcc, g77 and Lapack.
I told alot of things but not those most important :-)

[Julie]

serlancelot

The LAPACK library you get from Cygwin is already compiled but not tested on your machine. Moreover you do not get the latest version of LAPACK (I think they provide LAPACK 3.0 and the current version is LAPACK 3.1.1 - not sure)
That's why most user prefers to download/compile and install manually LAPACK on their machine, and also sometimes they have no choice as no pre-built package are available.
===========================================================================================
If you want to install it from netlib.
download lapack-lite-3.1.1.tgz from http://www.netlib.org/lapack
tar xfvz lapack-lite-3.1.1.tgz to uncompressed the archive
cd lapack-lite-3.1.1
Copy the make.inc.example to make.inc : cp make.inc.example make.inc
edit the make.inc to use the BLAS library you got from Cygwin if you were using ATLAS.
Otherwise do a make blaslib to use the Reference BLAS library (that will not give you good performance, but I am not sure you are looking for performance if you are on a Pentium II machine)
After you run the command make and it will compile and test the LAPACK library on your machine.
===========================================================================================
Now, if you want to get LAPACK on Windows without Cygwin, you will need a Vendor BLAS and LAPACK library(like MKL, ACML, etc..), this is the easiest solution at the moment. We are also working on deploying LAPACK on Microsoft Visual Studio. But you have to know that LAPACK is a Fortran Code and you will need a Fortran Compiler on your Windows machine, or you will have to deal with Calling Fortran from C that is sometimes tricky.

Hope it helps
Julie