Hi, I am trying to create a max_dens and max_temp sweep plot in yt. I am using the following code for n in range (0,118): fn = flashFolder+'super3d_hdf5_plt_cnt_%04d' % n pf = yt.load(fn) # load data #print pf.current_time c = pf.h.find_max('temp')[1] ax = 0 # take a line cut along the x axis # cutting through the y0,z0 such that we hit the max density #ray = ds.h.ortho_ray(ax, (c[1], c[2])) # ray with start and end point ray = pf.h.ray([0.,0.,0.],c) # Sort the ray values by 'x' so there are no discontinuities # in the line plot srt = np.argsort(ray['x']) plt.subplot(211) plt.semilogy(np.array(ray['x'][srt]), np.array(ray['dens'][srt])) plt.ylabel('dens') plt.subplot(212) plt.semilogy(np.array(ray['x'][srt]), np.array(ray['temp'][srt])) plt.xlabel('x') plt.ylabel('temp') plt.savefig("test_plots/den_temp_xsweep.png") and getting the the following error: IOError: [Errno 2] No such file or directory: 'test_plots/den_temp_xsweep.png' Any suggestion on how to fix this error is highly appreciated. THanks