Hi,
There is not such math function to round to 1.5 rounding always returns an int. to achieve this, multiply by 2 your value, round them, and then divide by two,
1.65*2 = 3.3
round(3.3) = 3
3/2 = 1.5
1.8*2 = 3.6
round(3.6) = 4
4/2 = 2
As for floor and ceiling. I'll see if I can do them in the next few days.
bye,
Jean