ADDED   mttroot/mtt/lib/comp/simple/cieqn.m
Index: mttroot/mtt/lib/comp/simple/cieqn.m
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/comp/simple/cieqn.m
@@ -0,0 +1,79 @@
+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
+
+% 
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+%     %%%%% Model Transformation Tools %%%%%
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% 
+% Matlab function  cieqn
+
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+% Copyright (c) P.J. Gawthrop, 1996.
+
+if nargin<8
+  eqnfile = 'stdout';
+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 = 0; % State causality
+
+for outport = 1:ports
+  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
+    fprintf(eqnfile, 'MTTdX(%1.0f,1) := %s;\n', state, ...
+                     varname(name,LHS_number,-LHS_cause));
+    % Print equation of form output = CR (state) 
+    eqn =  equation(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)
+    fprintf(eqnfile, '%s := MTTdz(%1.0f,1);\n', ...
+                             varname(name,LHS_number,LHS_cause), ...
+                             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(name,cr,args,LHS_number,state_cause, outport, ...
+                             bond_number,RHS_cause,1:ports);
+    fprintf(eqnfile, '%s',eqn);
+    structure(2) = nonstate;
+ end;
+end;
+
+
+
+
+
+
+
+
+