module eds;
%
% EDS V2.1
%
%
% Author: David Hartley
% GMD - German National Research Center
% for Information Technology
% D-53754 St Augustin
% Germany
%
% email: David.Hartley@gmd.de
%
%
% Description: EDS is a REDUCE package for symbolic analysis of partial
% differential equations using the geometrical approach of
% exterior differential systems. The package implements
% much of exterior differential systems theory, including
% prolongation and involution analysis, and has been
% optimised for large, non-linear problems.
%
%
% Requires: REDUCE 3.6 patched to 25 Apr 96 or later
%
% Created: 23/6/90 V0 as es.red (with Robin W Tucker)
%
% Modified: 8/8/90 V0.1 Added quasi-linear solving and consist-
% ency conditions for simultaneous eqns
% 11/9/90 V0.2 Added resimp in front of all subf, subsq
% etc as temporary fix for subf bug.
% 14/5/91 V0.3 Switched off factor (and on exp) in
% various routines to make simplifications
% work.
% 22/5/91 V0.4 Added subs2 in front of all resimp as
% temporary fix for unseen power LET rule
% bug.
% 26/11/91 V0.5 Altered algorithm in regchn so that
% alpha coefficients are not chosen until
% entire chain has been constructed.
% 30/6/92 V1 Renamed exsys.red.
% Radically altered exsolve to use modulo
% rather than contraction. Eliminated need
% for frame vectors. Added extra switches
% to allow given, random or (as before)
% generic combinations of the independence
% 1-forms to be used to construct a
% regular chain.
% Removed many utilities to tools.red.
% 23/7/92 V1.1 Added module `complete'
% 14/3/94 V1.2 Renamed eds.red.
% Modified for independent compilation,
% and for compatibility with new xideal.
% 25/4/96 V2.0 Total rewrite using parts of earlier
% versions.
% Added types for EDS and coframing.
% ?? ?? Made cross a bundle product when arguments
% share submanifold
% Other packages which must be loaded at run-time.
load_package solve,excalc,xideal;
create!-package('(
eds % Header module
edseval % Definition and manipulation of eds structure for exterior systems
edscfrm % Coframing structure for EDS
systems % Operations on exterior differential systems
tableaux % Definition and manipulation of tableaux using tab structure
contact % Contact systems on jet bundles and Grassmann bundles
invol % Cartan characters, reduced characters, involution test
prolong % Prolonged systems, tableaux
pullback % Pullback transformations
restrict % Restrict to a subset of a coframing
transfrm % Cobasis transformations
edspde % PDE interface to EDS
edsequiv % Check if EDS structures are equivalent
edsuser % Miscellaneous user functions
edsnorml % Converting exterior systems to internal form
edssolve % Specialised solvers for EDS
disjoin % Convert a variety to a disjoint union of sub-coframings
element % Generate a random integral element
edsaux % Miscellaneous support functions
edsexptl % Experimental (algebraic mode) operators
edspatch % Various patches for other parts of Reduce.
),'(contrib eds));
% Switches
fluid '(!*edsverbose !*edsdebug !*edssloppy !*edsdisjoint !*genpos
!*ranpos);
switch edsverbose; % prints calculation traces when on
switch edsdebug; % prints debugging information when on
switch edsdisjoint; % allows automatic variety decomposition when on
switch edssloppy; % treat quasilinear systems as semilinear
switch genpos; % Calculate characters with system in general
% position
switch ranpos; % Calculate characters with system in random
% position
put('genpos,'simpfg,'((t (setq !*ranpos nil))));
put('ranpos,'simpfg,'((t (setq !*genpos nil))));
% Global variables
fluid '(cfrmcob!* cfrmcrd!* cfrmdrv!* cfrmrsx!* pullback_maps
dependencies);
cfrmcob!* := nil; % cobasis for background coframing
cfrmcrd!* := nil; % coordinates for background coframing
cfrmdrv!* := nil; % structure equations for background coframing
cfrmrsx!* := nil; % restrictions for background coframing as pf
pullback_maps:= makelist {}; % list of maps used by last call to prolong
dependencies := makelist {}; % dependencies removed by pde2eds
flag('(pullback_maps dependencies),'share);
% Macros used throughout
symbolic smacro procedure eds_sys s;
cadr s;
symbolic smacro procedure eds_ind s;
caddr s;
symbolic smacro procedure eds_cfrm s;
cadddr s;
symbolic smacro procedure eds_props s;
car cddddr s;
symbolic smacro procedure cfrm_cob m;
cadr m;
symbolic smacro procedure cfrm_crd m;
caddr m;
symbolic smacro procedure cfrm_drv m;
cadddr m;
symbolic smacro procedure cfrm_rsx m;
nth(m,5);
% Macro for edscall
symbolic macro procedure edscall u;
% evaluate form cadr u within edsprotect
function edsprotect .
foreach x in cdr u collect
function list . mkquote car x . cdr x;
%%%% Form function for edscall
%%%
%%%
%%%put('edscall,'formfn,'formedscall);
%%%
%%%symbolic procedure formedscall(u,v,mode);
%%% % evaluate form cadr u within edsprotect
%%% function edsprotect .
%%% foreach x in formlis(cdr u,v,mode) collect
%%% function list . mkquote car x . cdr x;
% Macros from excalc for compilation
smacro procedure !*k2pf u;
u .* (1 ./ 1) .+ nil;
smacro procedure negpf u;
multpfsq(u,(-1) ./ 1);
smacro procedure lowerind u;
list('minus,u);
endmodule;
end;