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[Lapack] LAPACK for Windows

LAPACK is just a library. If you wish to use it, you need to link  
against that library.
The problem is that at the moment, the library depends on the compiler  
and relies on symbols from the compiler library. for example: all the  
system calls, but they are some others.
If you tried to link a C program with the LAPACK library, it give you  
a bunch of undefined symbol linked to the Intel Fortran Compiler. I  
tried to remove those dependancies but I do not  think this is the way  
to go...

If you are looking for performance, I will advice you to use the  
vendors library, they are generally tuned for the processor  
architecture (MKL for Intel Processors, ACML for AMD Processor [ I  
think this is free]).
Both of those libraries have a tuned LAPACK and BLAS implementation  
and an interface to C.
I did not perform tests between C and Fortran on Windows machines, But  
usually you are right, Fortran give slighter better performance, but  
they are not at all significant comparing to which library you use  
(Vendor against Netlib)
I did run performance tests on our Windows Machine (AMD Processor) and  
AMD was largely surpassing any other libraries (ATLAS, GOTO, MKL  

Let me know if this helps.
Julie LAngou

On Feb 15, 2008, at 9:38 AM, Sebastian Schuberth wrote:

Hi Julie,

However it is possible to link LAPACK to a C/C++ project if you  
have the
Fortran Libraries (i.e, that mean a Fortran compiler) and if you  
respect the
Fortran Call from C rules.

do I really need to have a "Fortran runtime" installed? If so, why
don't you statically link against the Fortran runtime so people would
be able to use your libraries without having Fortran installed?

My original question was exactly about "Fortran call from C rules". Do
you have a header file that implements these rules, so I could just
include that file into my C/C++ project, link against your
"LAPACK.lib" and be happy?

For information, CLAPACK-3.1.1 for Windows should be released very  
(sometime in March). This library will allow use to use the LAPACK  
without the need of a C Compiler.

You mean without the need for a Fortran compiler? The point is that I
believe the Fortran-compiled version to perform better than the
C-compiled version, which is why I wish to use the Fortran-compiled
version in my C/C++ project.


Sebastian Schuberth

Julie Langou; Research Associate in Computer Science
Innovative Computing Laboratory;
University of Tennessee from Denver, Colorado ;-)

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