// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) 2000 - 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 q=quart(x,orien)
    //
    //This function computes the quartiles of a vector or a matrix x.
    //
    //For a vector  or a matrix x, q=quart(x)  returns  in the vector q  the
    //three quartiles entries of x.
    //
    //q=quart(x,'r')  (or,   equivalently,  q=quart(x,1))   is  the  rowwise
    //quartiles range.  It returns in each  column of the 3xlength(x)-matrix
    //q, the quartiles of the corresponding column of x.
    //
    //q=quart(x,'c')  (or, equivalently,   q=quart(x,2))  is the  columnwise
    //interquartile range. It returns  in  each row of  length(x)x3-matrix q
    //the quartiles of each row of x.
    //
    //

    [lhs, rhs] = argn(0)
    if rhs==0 then error(msprintf(gettext("%s: Wrong number of input argument(s): %d or %d expected.\n"),"quart",1,2)), end

    function y = vperctl(x,p)
        //inline function wich computes percentiles of a vector
        k=isnan(x)
        x(k)=[];
        n=size(x,"*")
        x=gsort(x,"g","i")
        data=[0     100*(0.5:(n-0.5))./n  100;
        x(1), matrix(x,1,-1),       x(n)]
        y=interpln(data,p);
    endfunction

    if x==[] then q=%nan, return, end
    if rhs==1 then
        q=vperctl(x(:),[25 50 75])
        q=q(:)
    else
        q=[]
        if orien=="r"|orien==1 then
            for i=x
                p=vperctl(i,[25 50 75])
                q=[q p(:)]
            end
        else
            for i=x'
                p=vperctl(i,[25 50 75])
                q=[q;p(:)']
            end
        end
    end
endfunction