function k = Kinetics(r, ph, neighbor1, neighbor2, neighbor3, neighbor4)
% KINETICS  Kinetics class constructor.
% k = Kinetics(r, ph, neighbor1, neighbor2, neighbor3, neighbor4)
% Class Kinetics represents kinetics managers, which are classes
% that manage reaction mechanisms.  The reaction mechanism
% attributes are specified in a CTML file.
% Instances of class :mat:func:`Kinetics` are responsible for evaluating reaction rates
% of progress, species production rates, and other quantities pertaining to
% a reaction mechanism.
%
% :param r:
%     If ``r`` is an instance of class :mat:func:`Kinetics`, a copy of the instance
%     is returned. In this case, ``r`` should be the only argument. Otherwise, ``r``
%     must be an instance of class :mat:func:`XML_Node`.
% :param ph:
%     If ``r`` is an instance of :mat:func:`XML_Node`, ``ph`` is an instance of class
%     :mat:func:`ThermoPhase`. Otherwise, optional.
% :param neighbor1:
%     Instance of class :mat:func:`ThermoPhase` or :mat:func:`Solution` representing a
%     neighboring phase.
% :param neighbor2:
%     Instance of class :mat:func:`ThermoPhase` or :mat:func:`Solution` representing a
%     neighboring phase.
% :param neighbor3:
%     Instance of class :mat:func:`ThermoPhase` or :mat:func:`Solution` representing a
%     neighboring phase.
% :param neighbor4:
%     Instance of class :mat:func:`ThermoPhase` or :mat:func:`Solution` representing a
%     neighboring phase.
% :return:
%      Instance of class :mat:func:`Kinetics`
%

% indices for bulk phases in a heterogeneous mechanism.
% initialize < 0 so that bulk phases will not be included.
ineighbor1 = -1;
ineighbor2 = -1;
ineighbor3 = -1;
ineighbor4 = -1;

% if only one argument is supplied, and it is an instance of
% 'Kinetics', return a copy of this instance
if nargin == 1
    if isa(r, 'Kinetics')
        k = r;
        return
    else
        error('wrong number of arguments')
    end
end

% if more than one argument, first one must be an XML_Node
% instance representing the XML tree
if ~isa(r, 'XML_Node')
    error('first argument must be an XML_Node object')
end

k.owner = 1;
ixml = xml_hndl(r);

% get the integer indices used to find the stored objects
% representing the phases participating in the mechanism.
iphase = thermo_hndl(ph);
if nargin > 2
    ineighbor1 = thermo_hndl(neighbor1);
    if nargin > 3
        ineighbor2 = thermo_hndl(neighbor2);
        if nargin > 4
            ineighbor3 = thermo_hndl(neighbor3);
            if nargin > 5
                ineighbor4 = thermo_hndl(neighbor4);
            end
        end
    end
end
k.id = kinetics_get(ixml, 0, iphase, ineighbor1, ineighbor2, ineighbor3, ...
    ineighbor4);
if k.id < 0
    error(geterr);
end

k = class(k, 'Kinetics');