Daylight Factor rounded values

mostapha · February 27, 2018, 11:09pm

Since daylight factor is a division of illuminance at the sensor point by the sky illuminance the value of 10,000 vs 100,000 doesn’t make a difference in the final results. The reason to pick 100,000 over 10,000 is what is mentioned in this discussion: https://www.radiance-online.org//pipermail/radiance-general/2009-December/006413.html
It is intentional. We’re using a software with %5-10 error because of the stochastic model of calculation. We had this discussion early on and decided to round all the numbers which will saves us memory (integer vs float) and is fine from the accuracy point of view. If you want to get the original values you should change these line.

ladybug-tools/honeybee/blob/af1a64888e03f6cefe893e34f9799197dbeae34c/honeybee/radiance/analysisgrid.py#L267-L277


if mode == 0:
    values = (tuple(int(float(r)) for r in inf.next().split())
              for count in xrange(end))
elif mode == 1:
    # binary 0-1
    values = (tuple(1 if float(r) > 0 else 0 for r in inf.next().split())
              for count in xrange(end))
else:
    # divide values by mode (useful for daylight factor calculation)
    values = (tuple(int(float(r) / mode) for r in inf.next().split())
              for count in xrange(end))

Keep in mind that this method is used by all the recipes and it will make all the results to be float instead of integer. If you only want to change it for daylight factor it is in line 276.

Now why do you need the float value?