// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) 1999 - INRIA - Carlos Klimann
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution.  The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
//

function mom= cmoment(x,ord,orien)
    //
    //This function computes the central moment of all orders of a vector or
    //matrix x.
    //
    //For a vector or matrix x, mom=cmoment(x,ord) returns in the scalar mom
    //the moment of order ord of all the entries of x.
    //
    //mom=cmoment(x,ord,'r')(or, equivalently, mom=cmoment(x,ord,1)) returns
    //in  each entry of the  row vector mom the moment  of order ord of each
    //column of x.
    //
    //mom=cmoment(x,ord,'c')(or, equivalently, mom=cmoment(x,ord,2)) returns
    //in each entry of the column vector mom the moment of order ord of each
    //row of x.
    //
    //Nota: In the   calculations the  divisor is  n-1  ,  where  n  is  the
    //dimension of the data vector.
    //
    //References:  Wonacott, T.H. & Wonacott, R.J.; Introductory
    //Statistics, J.Wiley & Sons, 1990.
    //
    //
    [lhs,rhs]=argn(0)
    if rhs<2 then error(msprintf(gettext("%s: Wrong number of input arguments: %d to %d expected.\n"),"cmoment",2,3)), end
    if x==[]|ord==[] then mom=%nan, return, end
    if rhs==2 then
        if ord==1 then mom=0, return, end
        le=length(x)
        m=sum(x)/le
        mom=sum((x-m).^ord)/(le)
        return
    elseif rhs==3 then
        le=size(x,orien)
        m=mean(x,orien)
        if orien=="r"|orien==1 then
            m=m(ones(le,1),:)
        elseif orien=="c"|orien==1 then
            m=m(:,ones(le,1))
        else error(msprintf(gettext("%s: Wrong value for input argument #%d: ''%s'', ''%s'', %d or %d expected.\n"),"cmoment",3,"r","c",1,2)),
        end
        mom=sum((x-m).^ord,orien)/(le)
        return
    else error(msprintf(gettext("%s: Wrong number of input arguments: %d to %d expected.\n"),"cmoment",2,3)),
    end
endfunction