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+
+// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+// Copyright (C) 2001 - 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 [s]=center(x,orient)
+    //
+    //This function  computes s,  the centered version  of the
+    //numerical matrix x.
+    //
+    //For a vector  or a matrix x, s=center(x)  returns in the
+    //(i,j)   coefficient   of   the   matrix  s   the   value
+    //(x(i,j)-xbar), where  xbar is the mean of  the values of
+    //the coefficients of x.
+    //
+    //s=center(x,'r') (or, equivalently, s=center(x,1)) is the
+    //rowwise center reduction of  the values of x. It returns
+    //in  the entry  s(i,j) the  value  (x(i,j)-xbarv(j)) with
+    //xbarv(j) the mean of the values of the j column.
+    //
+    //s=center(x,'c') (or, equivalently, s=center(x,2)) is the
+    //columnwise  centre reduction  of  the values  of x.   It
+    //returns in the  entry s(i,j) the value (x(i,j)-xbarh(i))
+    //with xbarh(i) the mean of the values of the i row.
+    //
+
+    [lhs,rhs]=argn(0)
+    if (rhs<1)|(rhs>2) then error(msprintf(gettext("%s: Wrong number of input arguments: %d to %d expected.\n"),"center",1,2)), end
+    if x==[] then s=%nan, return, end
+    [m n]=size(x);
+    if rhs==1
+        xbar=(sum(x)/(m*n))
+        s=x-(ones(m,n)*xbar)
+    elseif orient=="c"|orient==2 then
+        xbar=sum(x,"c")/n
+        s=x-(xbar*ones(1,n))
+    elseif orient=="r"|orient==1 then
+        xbar=sum(x,"r")/m
+        s=x-(ones(m,1)*xbar)
+    else error(msprintf(gettext("%s: Wrong value for input argument #%d: ''%s'', ''%s'', %d or %d expected.\n"),"center",2,"r","c",1,2)),
+    end
+endfunction