.. Documentation for the header file dolfin/fem/PETScDMCollection.h

.. _programmers_reference_cpp_fem_petscdmcollection:

PETScDMCollection.h
===================

.. note::
    
    The documentation on this page was automatically extracted from the
    DOLFIN C++ code and may need to be edited or expanded.
    

.. cpp:class:: PETScDMCollection

    *Parent class(es)*
    
        * :cpp:class:`PETScObject`
        
    This class builds and stores of collection of PETSc DM objects
    from a hierarchy of FunctionSpaces objects. The DM objects are
    used to construct multigrid solvers via PETSc.
    
    Warning: This classs is highly experimental and will change


    .. cpp:function:: PETScDMCollection(std::vector<std::shared_ptr<const FunctionSpace>> function_spaces)
    
        Construct PETScDMCollection from a vector of
        FunctionSpaces. The vector of FunctionSpaces is stored from
        coarse to fine.


    .. cpp:function:: DM get_dm(int i)
    
        Return the ith DM objects. The coarest DM has index 0. Use
        i=-1 to get the DM for the finest level, i=-2 for the DM for
        the second finest level, etc.


    .. cpp:function:: void check_ref_count() const
    
        These are test/debugging functions that will be removed


    .. cpp:function:: void reset(int i)
    
        Debugging use - to be removed


    .. cpp:function:: static std::shared_ptr<PETScMatrix> create_transfer_matrix(const FunctionSpace& coarse_space, const FunctionSpace& fine_space)
    
        Create the interpolation matrix from the coarse to the fine
        space (prolongation matrix)