.. _DFP:

``DFP``
=======

If ``BFGS`` is used, then by default, the
Broyden [`19 <references.html#bfgs1>`__]-Fletcher [`20 <references.html#bfgs2>`__]-Goldfarb [`21 <references.html#bfgs3>`__]-Shanno [`22 <references.html#bfgs4>`__]
method will be used to optimize geometries. The older
Davidon-Fletcher-Powell method can be invoked by also specifying
``DFP``. This is intended to be used for comparison of the two methods.