Compute a new time series where each interval has the value (a addNaN b) where a
and b are the corresponding intervals in the input time series. Sample:
:add
3.0
0.0
1.0
1.0
NaN
Input 1
1.0
0.0
1.0
1.0
NaN
Input 2
2.0
0.0
0.0
NaN
NaN
Use the fadd operator to get strict floating point behavior.