/* 
 * 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 features for (mainly) gravitational theory
 */

if get('ctensor,'version)=false then load(ctensor);
("A conformally flat metric helps demonstrate the curvature tensors")$
(ratwtlvl:false,ratfac:true);
derivabbrev:true;
dim:4;
ct_coords:[x,y,z,t];
lg:a*ident(4);
dependencies(a(t));
("cmetric() computes the metric inverse:")$
cmetric();
ug;
("christof() computes the Christoffel-symbols of the 1st and 2nd kind")$
christof(mcs);
("ricci() computes and optionally displays the mixed-index Ricci tensor")$
ricci(true);
("uricci() computes the contravariant Ricci tensor")$
uricci(true);
("riemann() computes the (3,1) Riemann-tensor")$
riemann(true);
("The covariant Riemann-tensor is obtained with lriemann()")$
lriemann(true);
("While uriemann() computes the contravariant Riemann tensor")$
uriemann(true);
("The mixed-index Einstein tensor is computed by einstein()")$
einstein(true);
("The covariant Einstein tensor is computed by leinstein()")$
leinstein(true);
("Rinvariant obtains the Kretchmann-invariant:")$
rinvariant();
("The Weyl tensor is empty for a conformally metric")$
weyl(true);

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