controller_q_proportional(demands, orflows, orqueues, celldata, ts, idx)

function new_orflows = controller_q_proportional(demands, orflows, orqueues, celldata, ts, idx)
% CONTROLLER_Q_PROPORTIONAL - implementation of Proportional Queue Controller.
%
% Call:   new_orflows = controller_q_proportional(demands, orflows, orqueues, celldata, ts, idx)
%
% Parameters:
%             demands  - vector of on-ramp demands; 
%             orflows  - vector of on-ramp flows generated by ML controller,
%                        same size as 'demands';
%             orqueues - vector of current on-ramp queue sizes, same size as 'demands';
%             celldata - array of freeway cell data structures, whose length
%                        must be the same as size of 'demands';
%             ts       - sampling period;
%             idx      - index of the cell with given on-ramp.
%
% Returns:   new_orflows - vector of proposed on-ramp flows.
%
% Last modified:   10/06/2006.

%
% Alex Kurzhanskiy   <[e-mail]>
%

K = size(demands, 1);
L = size(orflows, 1);
M = size(orqueues, 1);
N = size(celldata, 2);

if K ~= N
  error('CONTROLLER_Q_PROPORTIONAL: number of on-ramp demands does not match number of cells.');
end

if L ~= N
  error('CONTROLLER_Q_PROPORTIONAL: number of on-ramp flows does not match number of cells.');
end

if M ~= N
  error('CONTROLLER_Q_PROPORTIONAL: number of on-ramp queues does not match number of cells.');
end

if (idx < 1) | (idx > N)
  error('CONTROLLER_Q_PROPORTIONAL: invalid cell index.');
end

new_orflows         = orflows;

d                   = demands(idx, 1);  % demand
l                   = orqueues(idx, 1) - celldata(idx).ORqsize;  % overflow
orf                 = (celldata(idx).ORqcontroller.Kp / ts) * l  +  d;

new_orflows(idx, 1) = max([0 orf]);

return;