function m = Mixture(phases)
%
% MIXTURE - Multiphase mixtures.
%
%    Class Mixture represents
%    mixtures of one or more phases of matter.  To construct a mixture,
%    supply a cell array of phases and mole numbers:
%
%    >> gas = importPhase('gas.cti');
%    >> graphite = importPhase('graphite.cti');
%    >> mix = Mixture({gas, 1.0; graphite, 0.1});
%
%    Phases may also be added later using the addPhase method:
%
%    >> water = importPhase('water.cti');
%    >> addPhase(mix, water, 3.0);
%
%    Note that the objects representing each phase compute only the
%    intensive state of the phase -- they do not store any information
%    on the amount of this phase. Mixture objects, on the other hand,
%    represent the full extensive state.
%
%    Mixture objects are 'lightweight' in the sense that they do not
%    store parameters needed to compute thermodynamic or kinetic
%    properties of the phases. These are contained in the
%    ('heavyweight') phase objects. Multiple mixture objects may be
%    constructed using the same set of phase objects. Each one stores
%    its own state information locally, and synchronizes the phase
%    objects whenever it requires phase properties.
%
if nargin > 1
    error('Mixture: wrong number of arguments');
end

% create an empty mixture
m.mixindex = mixturemethods(0, 0, 0);
m.phases = phases;

m = class(m,'Mixture');

% if phases are supplied, add them
if nargin == 1
    if ~isa(phases,'cell')
        error('enter phases as a cell array');
    end

    % first column contains the phase objects, and the second column
    % the mole numbers of each phase
    [np nc] = size(phases);
    if nc ~= 2
        error('wrong size for phases cell array');
    end
    for n = 1:np
        addPhase(m, phases{n,1}, phases{n,2});
    end
    setTemperature(m, temperature(phases{n,1}));
    setPressure(m, pressure(phases{n,1}));
end