function output = Volume(material,prop1,units1,value1,varargin)%,prop2,units2,value2)

value1 = CheckUnits(prop1,units1,value1);

switch lower(material)

    case {'water','steam'}

        %% Water

        error(nargchk(7, 7, nargin, 'struct'))

        prop2 = varargin{1};

        units2 = varargin{2};

        value2 = varargin{3};

        value2 = CheckUnits(prop2,units2,value2);

        if strcmpi(prop1,'v')

            output = value1;

            return;

        elseif strcmpi(prop2,'v')

            output = value2;

            return;

        end

        pressure = Pressure(material,prop1,'',value1,prop2,'',value2);

        temperature = Temperature(material,prop1,'',value1,prop2,'',value2);

        output = Corr_Water_Volume(pressure,temperature);

    case {'saturated water','saturatedwater','saturated steam','saturatedsteam'}

        %% Saturated Water

        error(nargchk(4, 4, nargin, 'struct'))

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        temperature = Temperature('saturated water',prop1,'',value1);

        pressure = Pressure('saturated water',prop1,'',value1);

        output = Corr_SaturatedWater_Volume(pressure,temperature);

     case {'refrigerant','r-134a','r134a','hfc-134a','hfc134a',...

             '1,1,1,2-tetrafluoroethane','tetrafluoroethane'}

         %% Refrigerant

        error(nargchk(7, 7, nargin, 'struct'))

        prop2 = varargin{1};

        units2 = varargin{2};

        value2 = varargin{3};

        value2 = CheckUnits(prop2,units2,value2);

        if strcmpi(prop1,'v')

            output = value1;

            return;

        elseif strcmpi(prop2,'v')

            output = value2;

            return;

        end

        switch lower(prop1)

            case 't'

                temperature = value1;

                switch lower(prop2)

                    case 'p'

                        pressure = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Pressure(temperature,volume)-pressure,1/1000);

                    case 's'

                        entropy = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Entropy(temperature,volume)-entropy,1/1000);

                    case 'h'

                        enthalpy = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Enthalpy(temperature,volume)-enthalpy,1/1000);

                    otherwise

                        error('Therm:corr','No correlation found for given properties')

                end

            case 'p'

                pressure = value1;

                switch lower(prop2)

                    case 't'

                        temperature = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Pressure(temperature,volume)-pressure,1/1000);

%                     case 's'

%                         entropy = value2;

%                         x = fsolve(@(x) [Corr_Refrigerant_Pressure(x(1),x(2))-pressure;...

%                             Corr_Refrigerant_Entropy_pt(x(1),x(2))-entropy],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(1);

%                     case 'h'

%                         enthalpy = value2;

%                         x = fsolve(@(x) [Corr_Refrigerant_Volume_pt(x(1),x(2))-volume;...

%                             Corr_Refrigerant_Enthalpy_pt(x(1),x(2))-enthalpy],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(2);

                    otherwise

                        error('Therm:corr','No correlation found for given properties')

                end

            case 's'

                entropy = value1;

                switch lower(prop2)

                    case 't'

                        temperature = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Entropy(temperature,volume)-entropy,1/1000);

%                     case 'p'

%                         volume = value2;

%                         x = fsolve(@(x) [Corr_Refrigerant_Entropy_pt(x(1),x(2))-entropy;...

%                             Corr_Refrigerant_Volume_pt(x(1),x(2))-volume],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(2);

%                     case 'h'

%                         enthalpy = value2;

%                         x = fsolve(@(x) [Corr_Refrigerant_Entropy_pt(x(1),x(2))-entropy;...

%                             Corr_Refrigerant_Enthalpy_pt(x(1),x(2))-enthalpy],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(2);

                    otherwise

                        error('Therm:corr','No correlation found for given properties')

                end

            case 'h'

                enthalpy = value1;

                switch lower(prop2)

                    case 't'

                        temperature = value2;

                        volume = fzero(@(volume) Corr_Refrigerant_Enthalpy(temperature,volume)-enthalpy,1/1000);

%                     case 'p'

%                         volume = value2;

%                         x = fsolve(@(x)

%                         [Corr_Refrigerant_Enthalpy_pt(x(1),x(2))-enthalpy;...

%                             Corr_Refrigerant_Volume_pt(x(1),x(2))-volume],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(2);

%                     case 's'

%                         entropy = value2;

%                         x = fsolve(@(x) [Corr_Refrigerant_Enthalpy_pt(x(1),x(2))-enthalpy;...

%                             Corr_Refrigerant_Entropy_pt(x(1),x(2))-entropy],...

%                             [[0 4.520795660].*611.2;1/1000]);

%                         temperature = x(2);

                    otherwise

                        error('Therm:corr','No correlation found for given properties')

                end

            otherwise

                error('Therm:corr','No correlation found for given properties')

        end

        output = volume;

    case {'saturated refrigerant','saturated r-134a','saturated r134a','saturated hfc-134a',...

                'saturated hfc134a','saturated 1,1,1,2-tetrafluoroethane','saturated tetrafluoroethane',...

                'saturatedrefrigerant','saturatedr-134a','saturatedr134a','saturatedhfc-134a',...

                'saturatedhfc134a','saturated1,1,1,2-tetrafluoroethane','saturatedtetrafluoroethane'}

        %% Saturated Refrigerant

        error(nargchk(4, 4, nargin, 'struct'))

        switch lower(prop1)

            case 'v'

                volume = value1;

            case 't'

                temperature = value1;

                pressure = Corr_Refrigerant_SatPressure(temperature);

                volume = [Corr_Refrigerant_Volume_liquid(temperature) Volume(material,'t','',temperature,'p','',pressure)];

            otherwise

                error('Therm:corr','No correlation found for given properties')

        end

        output = volume;

    case 'air'

        %% Air

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Air_Volume(pressure,temperature);

    case {'carbon dioxide','co2'}

        %% Carbon Dioxide

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_CarbonDioxide_Volume(pressure,temperature);

    case {'hydrogen','h2'}

        %% Hydrogen

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Hydrogen_Volume(pressure,temperature);

    case {'helium','he'}

        %% Helium

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Helium_Volume(pressure,temperature);

    case {'nitrogen','n2'}

        %% Nitrogen

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Nitrogen_Volume(pressure,temperature);

    case {'oxygen','o2'}

        %% Oxygen

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Oxygen_Volume(pressure,temperature);

    case {'propane','c3h8'}

        %% Propane

        error(nargchk(4, 7, nargin, 'struct'))

        if ((nargin > 4) && (nargin < 7))

            error('Therm:nargchk:improperNumberOfInputs','Improper number of input arguments.')

        end

        if strcmpi(prop1,'v')

            output = value1;

            return;

        end

        if nargin == 7

            prop2 = varargin{1};

            units2 = varargin{2};

            value2 = varargin{3};

            value2 = CheckUnits(prop2,units2,value2);

            varargin{2} = '';

            if strcmpi(prop2,'v')

                output = value2;

                return;

            end

        end

        pressure = Pressure(material,prop1,'',value1,varargin{:});

        temperature = Temperature(material,prop1,'',value1,varargin{:});

        output = Corr_Propane_Volume(pressure,temperature);

    otherwise

        error('Therm:matChk', 'Unknown material')

end

return