function [bonds,status] = AE_cause(bonds);
% AE_cause - Causality for Flow amplifier component
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  AE_cause
% [bonds,status] = AE_cause(bonds)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.


status = -1;

% Check that there are exactly two bonds.
if check_bonds(bonds,2,'AE')==0
  return
end

% There are 2 ports; extract the information
e_1 = bonds(1,1);
f_1 = bonds(1,2);
e_2 = bonds(2,1);
f_2 = bonds(2,2);

% Port 1 must impose (zero) flow and port 2 have flow imposed
if (f_1==-1)|(f_2==1) % Conflict
  status = 1;
 else 					% Do the rest of the causality

   if f_1 == 0 				% Set port 1 effort
     f_1 = 1;
   end;
   
   if f_2 == 0 				% Set port 2 effort
     f_2 = -1;
   end;
   
   number_set = sum(sum([e_1 e_2]~=zeros(1,2) ));
   if number_set==0 			% Under causal
     status = -1;
   elseif number_set==1 		% Set the causality
     if e_1 == 0
       e_1 = -e_2;
     else
       e_2 = -e_1;
     end
     status = 0;
   elseif number_set==2 		% Check the causality
     if e_1==-e_2
       status = 0;
     else
       status = 1;
     end
 end;
end;
 
 bonds = [e_1 f_1
           e_2 f_2];

function [bonds,status] = AF_cause(bonds);
% AF_cause - Causality for Flow amplifier component
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  AF_cause
% [bonds,status] = AF_cause(bonds)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.

status = -1;

% Check that there are exactly two bonds.
if check_bonds(bonds,2,'AF')==0
  return
end

% There are 2 ports; extract the information
e_1 = bonds(1,1);
f_1 = bonds(1,2);
e_2 = bonds(2,1);
f_2 = bonds(2,2);

% Port 1 must impose (zero) effort and port 2 have effort imposed
if (e_1==1)|(e_2==-1) % Conflict
  status = 1;
 else 					% Do the rest of the causality

   if e_1 == 0 				% Set port 1 effort
     e_1 = -1;
   end;
   
   if e_2 == 0 				% Set port 2 effort
     e_2 = 1;
   end;
   
   number_set = sum(sum([f_1 f_2]~=zeros(1,2) ));
   if number_set==0 			% Under causal
     status = -1;
   elseif number_set==1 		% Set the causality
     if f_1 == 0
       f_1 = -f_2;
     else
       f_2 = -f_1;
     end
     status = 0;
   elseif number_set==2 		% Check the causality
     if f_1==-f_2
       status = 0;
     else
       status = 1;
     end
 end;
end;
 
 bonds = [e_1 f_1
           e_2 f_2];

function [bonds,status] = R_cause(bonds);
% R_cause - Causality function for a (multi-port) unicausal R component
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  R_cause
% [bonds,status] = R_cause(bonds)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.
 

% Find the number of ports
[ports,junk] = size(bonds);

% default undercausal status
statuses = -ones(ports,1);

% Force unicausality
for i = 1:ports
  if (bonds(i,1)~=0)&(bonds(i,2)~=0) % Both bonds set
    statuses(i) = bonds(i,1)~=bonds(i,2);
  elseif bonds(i,2)~=0               % Bond 1 set
    bonds(i,1) = bonds(i,2);
    statuses(i) = 0;
  elseif bonds(i,1)~=0               % Bond 2 set
    bonds(i,2) = bonds(i,1);
    statuses(i) = 0;
  end;
end;

if max(statuses)==1
  status = 1;
elseif min(statuses)==-1
  status = -1;
else
  status = 0;
end;
  

function ok = check_bonds(bonds,n,component);
% check_bonds - check to see correct number (n) of bonds.
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  check_bonds
% err = check_bonds(bonds,n);

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.
% Check that there are exactly two bonds.
[n_bonds,cols] = size(bonds);
if n_bonds~=n
  mtt_info(sprintf('MTT error: %s must have %1.0f (not %1.0f) bonds', ...
      component, n, n_bonds));
  ok=0;
else
  ok=1;
end

function  oneeqn(name,LHS_number,LHS_cause,RHS_number,RHS_cause,cr,args, ...
    eqnfile);
% oneeqn - prints a single equation
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  oneeqn
% oneeqn(name,LHS_number,LHS_cause,RHS_number,RHS_cause,cr,args,eqnfile)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



if nargin<7
  eqnfile = 'stdout';
end;


fprintf(eqnfile, '%s := %s;\n', ...
    varname(name, LHS_number,LHS_cause), ...
    cr2name(name,RHS_number,LHS_cause,RHS_cause,cr,args));