/* Copyright (C) 2004 Viktor T. Toth <http://www.vttoth.com/>
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * CTENSOR basics
 */

if get('ctensor,'version)=false then load(ctensor);
("To select a stock metric, use ct_coordsys")$
verbose:false;
ct_coordsys(spherical);

("The metric tensor is stored in the array lg")$
lg;

("A call to cmetric() sets up the inverse and other properties")$
cmetric();
ug;
diagmetric;

("Most metrics are available also as a frame base")$
cframe_flag:true;
ct_coordsys(spherical);

("The inverse frame base is in the array fri; lfg is the frame metric")$
fri;
lfg;

("Now, cmetric computes the frame base, and also the metric")$
cmetric();
fr;
ufg;
lg;

("You can also supply a set of transformation rules to ct_coordsys")$
ct_coordsys([r*cos(theta)*cos(phi),r*cos(theta)*sin(phi),
             r*sin(theta),[r,theta,phi]]);
cmetric();
fri;
lg:trigsimp(lg);

/* End of demo -- comment line needed by MAXIMA to resume demo menu */