function ignite_hp(gas)
% IGNITE_HP Solves the same ignition problem as 'ignite', but uses function
% conhp instead of reactor.
%
% Keywords: combustion, user-defined model, ignition delay, plotting
help ignite_hp
if nargin == 0
gas = Solution('h2o2.yaml', 'ohmech', 'none');
end
mw = molecularWeights(gas);
set(gas,'T',1001.0,'P',oneatm,'X','H2:2,O2:1,N2:4');
y0 = [temperature(gas)
massFractions(gas)];
tel = [0 0.001];
options = odeset('RelTol',1.e-5,'AbsTol',1.e-12,'Stats','on');
t0 = cputime;
out = ode15s(@conhp,tel,y0,options,gas,mw);
disp(['CPU time = ' num2str(cputime - t0)]);
if nargout == 0
% plot the temperature and OH mole fractions.
figure(1);
plot(out.x,out.y(1,:));
xlabel('time');
ylabel('Temperature');
title(['Final T = ' num2str(out.y(1,end)) ' K']);
figure(2);
ioh = speciesIndex(gas,'OH');
plot(out.x,out.y(1+ioh,:));
xlabel('time');
ylabel('Mass Fraction');
title('OH Mass Fraction');
end