input.xml

<simulation>
    <ffsocket name='elphy' mode='inet' pbc='false'>
        <address>localhost</address>
        <port>31415</port> <!-- ignored for mode='unix' or mode='shm' -->
    </ffsocket>
    <system>
        <initialize nbeads='1'>
            <file mode='xyz'>input.xyz</file>
        </initialize>
        <forces>
            <force forcefield='elphy'></force>
        </forces>
        <motion mode='minimize'>
            <optimizer mode='bfgs'></optimizer>
            <fixcom>True</fixcom>
        </motion>
    </system>
    <output prefix='ipi'>
        <properties stride='1' filename='out'>[step, potential]</properties>
        <trajectory stride='1' filename='pos'>positions</trajectory>
        <trajectory stride='1' filename='for'>forces</trajectory>
    </output>
</simulation>