compiletime load "module_ppp.so";
PPP obj = {};

aperture_width = 100;   # Aperture width on substrate in transport direction

obj.read("density.pos", "n");
obj.read("velocity.pos", "v");

# Define vertical flux component
obj.create_scalar("Fz", n*v_z);

# Make cut plane of data just below the substrate surface
obj.xy_plane(99.5, 10, "nearest_neighbour");  

# Reduce input data to cut-plane (this is the important command)
obj.reduce(); 

# Make another cut plane averaging over the aperture_width
# in order to get the line profile
obj.xz_plane(0, aperture_width/2, "average");

# Write line profile into TXT file
obj.write_txt("absorption_line.txt", 
              ["x", "avg_absorption", "rel_absorption"],
              [x, Fz, 100*Fz/Fz_max]);