function [T]=scale_pre(sx,sy,sz)
%
% [T]=scale_pre(sx,sy,sz)
% generates scaling matrix T

% filename must be "scale_pre.m"
% can also write
% function T=scale_pre(sx,sy,sz)
% without square brackets

T= [ sx  0   0  0;
     0  sy   0  0;
     0  0   sz  0;
     0  0   0  1];
 
