Added compiling instructions

README.md

@@ -10,5 +10,68 @@ by [John Gilbert](http://www.cs.ucsb.edu/~gilbert/) and
 This code has been modified to work with the latest version of Metis.
 All functions except for one (NodeBisect) currently work.  
 
-Compiling and usage insructions coming soon.
+
+Compiling
+---------
+
+The following instructions worked on Ubuntu linux (10.4), I think they 
+also work on 9.04.  I could _not_ get this to work on Ubuntu 6.06.
+
+1. Download and extract the experimental version of 
+  [metis](http://glaros.dtc.umn.edu/gkhome/metis/metis/overview).
+    wget http://glaros.dtc.umn.edu/gkhome/fetch/sw/metis/metis-5.0pre2.tar.gz
+    tar xzvf metis-5.0pre2.tar.gz
+    cd metis-5.0pre2/
+
+2. Fix a small compile bug with recent gcc libraries.  Edit `GKlib/trunk/gk_arch.h`
+  and add the line `#define __USE_POSIX199309` as line 25.  The file should read:
+
+        ... line 22
+        #if !defined(__USE_XOPEN2K)
+        #define __USE_XOPEN2K 
+        #define __USE_POSIX199309 
+        #endif
+        #include <execinfo.h>
+        #endif
+        ... line 29
+
+3. Configure metis for 64-bit integers.  _This step is only required
+  for 64-bit versions of Matlab._  We need to edit `include/metis.h`
+  and change `#define IDXTYPEWIDTH 32` to `#define IDXTYPEWIDTH 64`.
+  On my system, this change was to line 35.
+  (I also changed this variable in config/config.h, but that does
+  not appear to be necessary.)
+
+4. Configure metis for shared libraries. I believe this step is only 
+  required for 64-bit systems as well, but I haven't tested it.
+  We need to tell metis to compile with `-fPIC`.  Edit
+  `Makefile.in` and add `-fPIC` to `COPTIONS` on line 57.  Likewise, 
+  edit  `GKlib/trunk/Makefile` and add `-fPIC` to 
+  `COPTIONS` on line 63.
+
+5. Compile metis.
+
+        make all
+
+6. Download and compile metismex
+
+        git clone git://github.com/dgleich/metismex.git
+        cd metismex
+        matlab -nodisplay
+        >> mex -O -largeArrayDims -I../include -I../libmetis -I../GKlib/trunk ...
+            -L../build/Linux-x86_64/ -lmetis metismex.c -DLINUX -DUNIX
+
+7. Check that it works
+
+        >> A = spaugment(ones(5)); A(1,10) = 1; A(10,1) = 1; A(5,6) = 1; A(6,5) = 1;
+        >> [p1,p2] = metispart(sparse(A))
+        
+        p1 =
+        
+             1     2     3     4     5
+        
+        
+        p2 =
+        
+             6     7     8     9    10