# restart
# read the starting time from file
f=open('./output/time.txt','r')
t_0=int(f.read())
f.close()
# read the array from file
y = np.loadtxt('./output/y_t.txt')
print "start time evolution..."
t_start = time.time()
n_species = chemistry_obj.gas.n_species
for j in range(T_step):
# diffusion for dt/2
y = diffusion_solver.advance(y,n_species,dt/2.)
# chemical evolution for dt
chemistry_obj.advance(y,dt)
# diffusion for another dt/2
y = diffusion_solver.advance(y,n_species,dt/2.)
print j
# record data for every 100 time steps and the end of the simulation
if (j+1)%data_frequency == 0 or j+1 == T_step:
# save data for plot or restart
t = t_0 + (j+1)*dt
# save the time to file
f = open('./output/time.txt', 'w')
f.write(str(t))
f.close()
np.savetxt('./output/y_t.txt',y)
print "snapshot saved at t =",t
print "end of time evolution"
