function fv=fitSingle(globalPar, par, cax)
    %par is a nfunc x npar matrix of coefficients
    %globalPar is a row vector of global coefficients
    %cax is a column vector of time instances
    %cay are the function values
    
    %oneVector=ones(1,size(cax,1));%column vector
    
    A=globalPar(1);
    tau=globalPar(2);
    alpha=globalPar(3);
    
    k1=par(1);
    B=par(2);
    k2=par(3);
    dt=par(4);
    
    cax1=cax-dt;
    kt=k1./(k2-1/tau);
    ka=k1./(k2-alpha);
    e0=exp(-cax1/tau);
    e1=exp(-cax1*alpha);
    ek=exp(-cax1*k2);
    
    
    if alpha==1/tau
        fv=cax1.*e0;
        if k2==1/tau
            r0=k1.*cax1.*cax1.*ek;
        else
            r0=kt*(cax1.*e0-(e0-ek)/(k2-1/tau));
        end
    else
        q=tau/(alpha*tau-1);
        fv=q*(e0-e1);
        r0=zeros(size(cax1));
        if k2==1/tau
            r0=r0+q*k1*cax1;
        else
            r0=r0+q*kt*(e0-ek);
        end
        if k2==alpha
            r0=r0-q*k1*cax1;
        else
            r0=r0-q*ka*(e1-ek);
        end
    end
    
    fv=B*fv+(1-B)*r0;
    
    fv=fv*A;
    sel=cax1<0;
    fv(sel)=0;

end

%par=ones(2,