Figuring out configure flags

The system is a Fedora Core 8 system, which unfortunately uses the broken gcc 4.1.2, which would cripple ATLAS performance. Therefore, prior to installing ATLAS, I have installed gcc 4.2.1, with -prefix=/home/whaley/local/gcc-4.2.1 I therefore add the following lines to my .cshrc so that ATLAS will use this gcc (it is put first in the path), and will be able to find the gcc 4.2 libraries:
set path = (/home/whaley/local/gcc-4.2.1/bin $path)
setenv LD_LIBRARY_PATH /home/whaley/local/gcc-4.2.1/lib64:/home/whaley/local/gcc-4.2.1/lib

I source the C shell startup file, and then check that I'm now getting the correct compiler:

etl-opt8>source ~/.cshrc
etl-opt8>gcc -v
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --prefix=/home/whaley/local/gcc-4.2.1 --enable-languages=c
Thread model: posix
gcc version 4.2.1

Now, I don't need to pass a lot of flags to set what compiler to use, since ATLAS will find gcc 4.2 as the first compiler, and it will have the libraries it needs to work. However, I want to build dynamic libraries for this install, so I know I'll need to add the -shared configure flag; config will automatically add the required -fPIC flag to all gnu compilers so they can build shared object code.

Now, I do a top on etl-opt8 (the machine name) and see that I'm alone on the machine. Therefore, I will want to use the cycle-accurate x86-specific wall timer in order to improve the accuracy of my install. This requires me to figure out what the Mhz of my machine is. Under Linux, I can discover this with cat /proc/cpuinfo, which tells me cpu MHz : 2100.000. Therefore, I will throw -D c -DPentiumCPS=2100.

I want ATLAS to install the resulting libraries and header files in the directory
/home/whaley/local/atlas, so I'll pass -prefix=/home/whaley/local/atlas as well.

I want a 64 bit install, and to build a full LAPACK library, so I will also want to throw -b 64 and
--with-netlib-lapack-tarfile=/home/whaley/dload/lapack.tgz.

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Clint Whaley 2012-07-10