)</span>
    <span class="c">!! @note This subroutine initializes all the variables needed for advancing</span>
    <span class="c">!! the particles&#39; position and velocity. @endnote</span>
    <span class="c">!! This subroutine is specially useful when we need to define or initialize</span>
    <span class="c">!! values of parameters used to calculate derived quantities.</span>
    <span class="c">!! The intent of this subroutine is to work as a constructor of the module.</span>
    <span class="k">TYPE