1.4 Installing Python from Source

It is very likely that if you have a Unix system (other than Linux), Python will not be installed. However, downloading, building and installing Python is very simple and works on every platform on which OEChem is available. Go to http://www.python.org/download and get the latest source distribution.

Following that link above will bring you to a version-specific download page so you can download Python-2.*.*tgz (or similar for a different version number). Save this file in an empty directory and then follow the simplified directions below (or better yet, follow the INSTALL directions found in the .tgz file)

cd to the directory containing the Python-2.5.2.tgz file.
gunzip Python-2.5.2.tgz
tar -xvf Python-2.5.2.tar
cd Python-2.5.2
./configure
The main option to configure is a decision about the root of the install tree and whether or not to use gcc as the compiler.
By default, configure will choose /usr/local such that the application ends up in /usr/local/bin/python and the associated library files end up in /usr/local/lib/python2.5. Additionally, if gcc is in your path, the default configure will use gcc to build Python. It is important that the C compiler used to build Python match the version of the C compiler used to build PyOEChem.
If you are happy with the default then just run:
./configure
If you have an alternate place (such as /apps or /sw) then run configure as:
./configure -prefix=/apps
To use the native, system compiler instead of gcc:
./configure -without-gcc
make
As root: make install
As a normal user, start a new shell and type:
which python
and make sure it points to /usr/local/bin/python if you ran configure without a prefix option or to /apps/bin/python, /sw/bin/python, etc. depending on the actual prefix you fed configure in step 5.

				OEChem - Python Theory Manual

				OEChem - Python Theory Manual