You cannot do that.
The double() present in the first expression shows that EDP is an array of double precision numbers. The datetime() in EDPdate, reinforced with setting the TimeZone, shows that EDPdate is desired to be a datetime object. However it is not possible to store a datetime object in a double array .
You could convert the datetime object to a serial date number, which would potentially lose precision, and would certainly lose the timezone.
Have you considered changing from using an array to using a table() object?