I am using a custom weather file in epw format for validation of measured illuminance in DIVA. The epw weather file has time step starting at 1 to 24 while that of DIVA illluminance has output in one hour time steps starting at 0.5 i.e. from 12:30 am to 11:30 am . How is the irradiation at those time step input in the DIVA . Are the hourly irradiation value interpolated to get illuminance i.e. for illuminance at 10:30 am is the irradiation at 10:00 am and 11:00 am averaged to obtain irradiation value at 10:30 am?