plotfd(celldata, idx)

function plotfd(celldata, idx)
% PLOTFD - plot fundamental diagram for given freeway cell.
%
% Call:   plotfd(celldata, idx)
%
% Parameters:
%             celldata - array of freeway cell data structures;
%             idx      - index to this array, which should positive and
%                        not exceed the length of 'celldata'.
%
% Returns:   none.
%
% Last modified:   07/30/2006.

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

N = size(celldata, 2);  % number of cells

if (idx < 1) | (idx > N)
  error('PLOTFD: index exceeds matrix dimensions.');
end

dc = celldata(idx).FDrhocrit;
dj = celldata(idx).FDrhojam;
fm = celldata(idx).FDfmax;

ih = ishold;

plot([0 dc], [0 fm], 'g', 'LineWidth', 2);
hold on;
plot([dc dj], [fm 0], 'r', 'LineWidth', 2);
plot([dc dj], [fm 0], 'ko');

title(sprintf('FD for cell %d (%d lanes)', idx, celldata(idx).lanes));
xlabel('Density (vpm)');
ylabel('Flow (vph)');

if ih == 0
  hold off;
end

return;