def rel_humid_from_db_hr(db_temp, humid_ratio, b_press=<NUM_LIT>):
pw = (humid_ratio * <NUM_LIT:1000> * b_press) / (<NUM_LIT> + (humid_ratio * <NUM_LIT:1000>))<EOL>pws = saturated_vapor_pressure(db_temp + <NUM_LIT>)<EOL>rel_humid = (pw / pws) * <NUM_LIT:100><EOL>return rel_humid<EOL>
Relative Humidity (%) at humid_ratio (kg water/kg air), db_temp (C),
    and Pressure b_press (Pa).