function structure = cieqn(name, bond_number,bonds,direction,cr,args, ...
structure,CorI,eqnfile);
% cieqn - Equation function for a (multi-port) unicausal C or I component
% CorI = 1 for C, -1 for I; 0 for ISW
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %%%%% Model Transformation Tools %%%%%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Matlab function cieqn
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.3 1998/06/29 13:05:08 peterg
% %% Changed cieqn so that sign ignored.
% %%
% %% Revision 1.2 1997/12/04 13:48:00 peterg
% %% Added sign info to take account of direction of bonds.
% %%
% %% Revision 1.1 1997/04/09 10:18:26 peterg
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Copyright (c) P.J. Gawthrop, 1996.
if nargin<8
eqnfile = 'stdout';
end;
if (CorI==1)
comp_type = "C";
else
comp_type = "I";
endif
CorIorISW = CorI;
if CorIorISW==0 % ISW
CorI = -1;
end;
% Find the number of ports
[ports,junk] = size(bonds);
% Right-hand side causality
RHS_cause = (bonds(:,1)==CorI*ones(ports,1))*CorI
state_cause = zeros(ports,1); % State causality
for outport = 1:ports
# % Sort out direction
# if direction(outport,1) == 1
# sign = '+';
# else
# sign = '-';
# end;
sign = '+';
LHS_number = bond_number(outport);
if bonds(outport,1) == -CorI % Integral causality on this port
state = structure(1)+1;
LHS_cause = CorI;
% Print equation of form x_i = MTTx(i)
fprintf(eqnfile, '%s := MTTx(%1.0f,1);\n', ...
varname(name,LHS_number, state_cause), state);
% Print equation of form xdot = input - with sign
fprintf(eqnfile, 'MTTdX(%1.0f,1) := %s%s;\n', state, sign, ...
varname(name,LHS_number,-LHS_cause));
% Print equation of form output = CR (state)
eqn = equation(comp_type,name,cr,args,LHS_number,LHS_cause,outport, ...
bond_number,state_cause,1:ports);
fprintf(eqnfile, '%s',eqn);
structure(1) = state;
else % Derivative causality
nonstate = structure(2)+1;
LHS_cause = -CorI;
% Print equation of form zdot = MTTdz(i) -- with sign
fprintf(eqnfile, '%s := %sMTTdz(%1.0f,1);\n', ...
varname(name,LHS_number,LHS_cause), sign, ...
nonstate);
% Print equation of form MTTz(i) = z_i
fprintf(eqnfile, 'MTTz(%1.0f,1) := %s;\n', nonstate, ...
varname(name,LHS_number, state_cause));
% Print equation of form z_i = CR(input)
eqn = equation(comp_type,name,cr,args,LHS_number,state_cause, outport, ...
bond_number,RHS_cause,1:ports);
fprintf(eqnfile, '%s',eqn);
structure(2) = nonstate;
end;
end;