installation-instructions.md

@@ -202,7 +202,19 @@ export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$HOME/.local/lib"
 ```
 (Note that in MacOS the above should be `DYLD_LIBRARY_PATH` instead.)
 
-## Installing in a virtualenv
+## Installing in a [virtualenv](http://docs.python-guide.org/en/latest/dev/virtualenvs/)
+
+To install graph-tool in a virtualenv we need to activate it before running configure
+```bash
+$ cd my_project
+$ source venv/bin/activate
+$ cd graph-tool-X.XX
+$ ./configure --prefix=$HOME/.local
+$ make install
+```
+The `--prefix` is necessary only so that non-python-related parts are installed in the correct place.
+
+**Important:** It is important that the boost-python dependency is compiled against the same Python version that is used in the virtualenv.
 
 ## Memory requirements for compilation