Sum Function clarification

[navins]

Kindly refer to the below image:

AFL Code:

NewDay = Status("firstbarinrange") OR Day() != Ref(Day(), -1);
BarsSince_NewDay = BarsSince(NewDay) + 1;
SumDays = Sum(NewDay, BarsSince_NewDay);

Filter = 1;
AddColumn(NewDay, "New Day");
AddColumn(BarsSince_NewDay, "Bars Since New Day");
AddColumn(SumDays, "Sum Days");

The Sum Function is not giving any results on the first day and am not sure of the reason, if any of the seniors could help on this please.

[Tomasz]

You should be using SumSince() function instead http://www.amibroker.com/f?sumsince

Using the Sum in a way you do (variable period) is significantly less efficient.

[navins]

Noted Dr. Tomasz, thank you!

[fxshrat]

@navins

The Sum Function is not giving any results on the first day and am not sure of the reason,

As for the reason why it shows NULL (Emtpy) for first day:
There has been change in Sum/MA functions in AB 6.03.

Questions regarding AFL-logic of bars

You are using very old (trial) version 6.0 of six years ago. It is not an error but implementation decision Since AmiBroker 6.03 it has been subject to change AFL: Sum(array,N) outputs NULL values for indices starting from 0 upto index N-1 instead of N That change included MA() function Since AB 6.03 MA() function outputs start of array the way as seen in my example pictures above. FYI, most recent public version is 6.38 (available to members only).

So since it returns NULL in first element in your example the sum for the whole day becomes NULL also.

[mradtke]

To start accumulating values from the beginning of the array, you could use the Cum() function instead of Sum() or SumSince():

CumDays = Cum(NewDay);