MCNPX on MacOSX
(tested on PPC 10.4.7 with gcc 4.0.1)


------------------------------
STEP 1, INSTALL a F90 COMPILER
------------------------------


Get a f90 compiler, for example g95,available from
www.g95.org. Follow the instructions and make a symbolic link
of the binary in a directory, for example /usr/local/bin/,
included in your environmental variable $PATH,


> sudo ln -sf /directory/g95-install/bin/powerpc-apple-darwin6.8- g95 /usr/local/bin/g95


---------------------
STEP 2, COMPILE MCNPX
----------------------


The following assumes that you have made a directory
/mcnpx_26b/ containing the source code tree 'v26b.tar.gz'
and the data files 'DATA.tar.gz', and that you will install
mcnpx in a new directory /mcnpx_26b/mcnpx.


> tar -zxvf v26b.tar.gz
> cd v26b


You need to replace the 'config.guess' and 'config.sub' with
something more recent including macosx. These files are
availabe on macosx in /usr/share/automake-1.6/. Replace the
config files:


> find . -name "config.guess" -print -exec cp /usr/share/ automake-1.6/config.guess {} \;
> find . -name "config.sub"   -print -exec cp /usr/share/ automake-1.6/config.sub {} \;


Now make the install directory and start configuration:


> mkdir mcnpx
> cd mcnpx
> ../v26b/configure \
   --with-CC='/usr/bin/gcc' \
   --with-CFLAGS='-DUNIX=1 -DLINUX=1' \
   --with-FC='g95' \
   --with-FFLAGS='-DUNIX=1 -DLINUX=1 -DG95=1 -fsloppy-char' \
   --with-LDFLAGS='-Wl,-m' \
   --prefix='/mcnpx_26b/mcnpx'


The fortran option '-fsloppy-char' is needed for an
integer/character issue at runtime. The LDFLAGS '-Wl,-m' is
necessary to ignore multiple definitions of the symbol
_etime_.


The link commands in the generated makefiles include
'-lcrt1.o' which should not be there. Remove all occurances
of '-lcrt1.o':


> find . -name "Makefile.h" -print -exec sed -i -e "s/-lcrt1.o// g" {} \;


and compile everything:


> make install


This will generate the executables in /mcnpx_26b/mcnpx/bin/


-------------------------
STEP 3, GET MCNPX RUNNING
-------------------------


You need to complete the installation with the data libraries
in a directory given by the environmental variable $DATAPATH
or in the default directory /mcnpx_26b/mcnpx/lib/. In this
directory should be a file with the name 'xsdir'.


Expand the file 'DATA.tar.gz' from the distribution in the
directory /mcnpx_26b/:


> cd ../
> tar -zxvf DATA.tar.gz


Move the files to the directory /mcnpx_26b/mcnpx/lib/


> mv DATA/* mcnpx/lib/


Copy the file 'xsdir1' to 'xsdir'


> cp mcnpx/lib/xsdir1 mcnpx/lib/xsdir


The installation is ready. Put the path to your mcnpx
executable in your $PATH and run some test problems.