ADDED   mttroot/mtt/lib/comp/simple/RS_cause.m
Index: mttroot/mtt/lib/comp/simple/RS_cause.m
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/comp/simple/RS_cause.m
@@ -0,0 +1,48 @@
+function [bonds,status] = RS_cause(bonds);
+% Causality for RS component
+
+%SUMMARY RS: resistor with entropy generation
+%DESCRIPTION Port[in]: a simple one port resistor
+%DESCRIPTION Port[out]: thermal power - effort is temperature, flow is entropy flow
+%DESCRIPTION Not bicausal (yet)
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Copyright (c) P.J. Gawthrop, 1997.
+
+status = -1;
+
+% Check that there are exactly two bonds.
+if check_bonds(bonds,2,'RS')==0
+  return
+end
+
+% There are 2 ports; extract the information
+in_bonds = bonds(1,:);
+out_bonds = bonds(2,:);
+
+% Port [in] is an ordinary resistor
+[in_bonds,in_status] = R_cause(in_bonds); 
+
+% Port [out] has the same causality pattern as an ordinary resistor
+[out_bonds,out_status] = R_cause(out_bonds); 
+
+% Reconstruct the bonds
+bonds = [in_bonds; out_bonds];
+
+% Generate an overall status
+if (in_status==1)|(out_status==1)
+  status = 1;
+elseif
+  (in_status==-1)|(out_status==-1)
+  status=-1;
+else
+  status = 0;
+end;
+
+

ADDED   mttroot/mtt/lib/comp/simple/RS_eqn.m
Index: mttroot/mtt/lib/comp/simple/RS_eqn.m
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/comp/simple/RS_eqn.m
@@ -0,0 +1,55 @@
+function  structure = RS_eqn(name,bond_number,bonds,direction,cr,args, ...
+    structure,eqnfile);
+% RS_eqn - equations for flow-modulated resistor
+% 
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+%     %%%%% Model Transformation Tools %%%%%
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% 
+% Matlab function  RS_eqn
+% RS_eqn(name,bond_number,bonds,direction,cr,args, ...
+%    structure,eqnfile);
+
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+% Copyright (c) P.J. Gawthrop, 1997.
+
+
+if nargin<6
+  eqnfile = 'stdout';
+end;
+
+% Check that there are exactly two bonds.
+ports = 2;
+if check_bonds(bonds,ports,'RS')==0
+  return
+end
+
+
+% There are 2 ports; extract the information
+in_bonds = bonds(1,:);
+out_bonds = bonds(2,:);
+in_direction = direction(1,:);
+out_direction = direction(2,:);
+
+% Do port [in] - a standard resistor
+structure = R_eqn(name,bond_number(1),in_bonds,in_direction,cr,args, ...
+    structure,eqnfile);
+
+% Do port [out] - the thermal bit. RS is power conserving.
+% This computes f_2 = e_1*f_1/e_2 or  e_2 = e_1*f_1/f_2
+fprintf(eqnfile,'%s := %s*%s/%s;\n' , ...
+    varname(name,bond_number(2), -out_bonds(1)), ...
+    varname(name,bond_number(1),  1), ...
+    varname(name,bond_number(1), -1), ...
+    varname(name,bond_number(2), out_bonds(1)) );
+
+