[sun_rise, sun_set] = sun_up_down(date, latitude, longitude, daylight_saving, UTC)

First it is important to specify two variables for Matlab to write on as shown in the title. Otherwise you will only see the sunrise time.
The date has to be enter in 'yyyy-mm-dd' format, otherwise it wont work. This date is used to calculate the Julian day. Afterwards the Julian day is used to calculate the sunrise and sunset times.
Latitude and longitude has to be entered in full degrees.
If theres daylight saving active at the specified date and location enter the full hour value your location uses for daylight savings (usually 1 but it can be different) for this value, otherwise enter zero.
For UTC enter the plus or minus value for your location without daylight saving if it is active.
This function calculates the times for sunrise and sunset and writes them on the variables in the format 'hh:mm'.