classdef CCREClass<CREClass 
    %CCRECLASS calculate the Conditional Cummulative Residual Entropy
    %   This class uses the CREClass options
    %   
    
    properties
        %the data field inherited from the CREClass will contain the data
        %to calculate the CCRE on. 
        %the nBin field inherited from the CREClass will contain the number
        %of bins if UseHistProxy is set. 
    end
    properties
        DataRef %This parameter will contain the reference set.
        nBinRef %number of "bins" to use for the reference distribution
        EqualSizeBinFlagRef=false;  %set to true to get equally spaced bins, default : false, put an equal number of points per bin. 
        EdgesRef; %edges for the bins of the reference function.  %todo, turn into dep. variable!
    end
    properties(SetAccess=private) %make read only
                CCRE %parameter containing the conditional Cumulative Residual Entropy
    end
    properties(Constant)
        UseHistProxyFlagRef=true; % this value is there to remind the user that we will have to bin the reference image. The actual value is not used in the code
    end
    
    methods %constructor
        function obj = CCREClass()
            %CCRECLASS Construct an instance of this class
            %   Detailed explanation goes here
            obj@CREClass;
        end
    end
    methods %set and get functions
        function set.DataRef(obj,val)
            if isnumeric(val)
                obj.DataRef=val;
            else
                error('please enter numeric array/matrix as reference');
            end
        end
        function set.nBinRef(obj,val)
            nBinFromCRE=obj.nBin; %park the current value of nBin
            obj.nBin=val; %use the check system from CREClass
            obj.nBinRef=obj.nBin;
            obj.nBin=nBinFromCRE; %restore the current value of nBin
        end
    end
    methods %user callable functions
        function CalcEdgesRef(obj)
            % copy the info for "ref" to a CRE object
            Stmp=CREClass('ref',obj.DataRef...
                ,'nbin',obj.nBinRef...
                ,'EqualSizeBinFlag',obj.EqualSizeBinFlagRef...
                ,'UseHistProxyFlag',obj.UseHistProxyFlagRef...
                );
            Stmp.CalcEdges;
            obj.EdgesRef=Stmp.Edges;
        end
        %% CCRE A|B
        %
        % $$CCRE = \varepsilon (A) - E[\varepsilon(A|B)]$$
        %
        % $$\varepsilon(A) = -\sum_{\lambda}F_c^A(\lambda)logF_c(A^(\lambda)$$
        % $$F_c^A(\lambda)=\int_{\lambda}^{\infty}p^A(l)dl$$
        %
        % $$E[\varepsilon(A|B)]= \sigma_{\kappa} p^B(\kappa)*\varepsilon(A|B)$$
        %
        % $$\varepsilon(A|B) = \sigma_{\lambda}F_c^{A|B}(\lambda)log
        % F_c^{A|B}(\lambda)$$
        %
        % $$F_c^{A|B}(\lambda) = \int_{\lambda}^{\infty}p^{A,B}(l,k)/p^B(\kappa)dl$$
        %
        % see equation 7 in wan and Vemuri
        function Calc(obj)
            Calc@CREClass(obj); %calculate the CRE for the data. 
            if isempty(obj.DataRef);return;end %if no refdata given, return;
            %calculate histogram for RefData
            EVarEpsDataGivenRef=0; %clear previous calculations
            %get the edge definition. 
            % a bit of a workaround, I don't plan to reprogram the function
            if isempty(obj.EdgesRef)
                obj.CalcEdgesRef;
            end
            [pDataRef,E]=histcounts(obj.DataRef(:),obj.EdgesRef,'Normalization','probability');
            for k=1:numel(pDataRef) %loop over the bins in pDataRef NB: must be equal to the bins in JointHist for the Ref
                if pDataRef(k)==0;continue;end% if no data at this line go to the next
                ind=E(k)<=obj.DataRef(:)&obj.DataRef(:)<E(k+1); %get an index to all points in Ref data inside the current bin
                CRE_DataGivenDataRef=CREClass('data',obj.Data(ind)...
                    ,'nbin',obj.Edges...
                    );
                CRE_DataGivenDataRef.Calc;
                EVarEpsDataGivenRef=EVarEpsDataGivenRef+pDataRef(k)*CRE_DataGivenDataRef.CRE; % I really have to check this line on merit. 
            end
            obj.CCRE=obj.CRE-EVarEpsDataGivenRef;

        end
    end
end