To build NWChem, you will need to download the source,
configure it, and then build and test it. These steps, and any known
limitations, are described in the sections below.

You can get NWChem from the NWChem website. These instructions are for NWChem version 4.7.

NWChem supports PathScale EKOPath compilers and it is already configured to use tuned optimization options specific to the PathScale
compiler. The regular NWChem instructions should be followed for building, installing, and running.
In brief, the following steps are sufficient to build NWChem:

tar -xjf nwchem-4.7.tbz
cd nwchem-4.7
export NWCHEM_TOP=`pwd`
export NWCHEM_TARGET=LINUX64
export NWCHEM_MODULES=all
cd src
make nwchem_config NWCHEM_MODULES=all
make FC=pathf90 _FC=pathf90 CC=pathcc

This results in an executable called nwchem in the bin/LINUX64 sub-directory. Please refer to the NWChem
documentation for information on running the software.

Increased performance may be obtained by using an alternate BLAS library. The necessary steps to achieve this are described in the
NWChem INSTALL file.

If the NWChem compilation fails on the file bas_checksum.F this is probably due to an excessively long directory name. The NWChem build process macro expands the directory name into a variable in the Fortran source code and if this exceeds 64 characters, it results in a broken fixed- Fortran program. The solution to this is to reduce the depth of the directory tree or rename directories to shorten the pathname. This problem is referred to in the NWChem INSTALL file and in src/basis/GNUmakefile.

We recommend you record what steps you took, along with their output, in case of problems. You can include this in your email to support. Here is an example of changing a make command to record the output in a text file:

							make foo 2>&1 | tee make-foo-log.txt
	

If you have any comments or suggestions about additions to these pages, please contact support@pathscale.com.