Is there a way for AFL to get the database's base time interval?

[PeterD]

I have a chart layout that includes a 5-second chart, but it shows 1-minute data if I am using a DB with a base time interval of 1 minute. I'd like to make the chart blank instead of plotting misleading data, but Interval() only returns the user-selected interval, not the base time interval of the underlying DB.

Is there a way for AFL to get the base time interval? (If not, the workaround that I have in mind is to use a naming convention on the DB filename and check the filename for the base interval).

[alligator]

Using AFL I would compute the timestamp difference between 2 bars. Try something like that:

TN = 3600*Hour() + 60*Minute() + Second(); 
DTN = TN - Ref(TN,-1);
MDTN = Lowest(ValueWhen(DTN > 0, DTN));
dbi = LastValue(MDTN);
sec = Param("Expected DB Interval (sec)", 5, 5, 300, 5);
if (dbi == sec) {
	Plot(C,"",colorDefault,styleLine); // or whatever
} // else do nothing

Modify it by adding to TN days (& higher timeframes) if you deal with this kind of database.

[fxshrat]

dt = DateTime();
dt_diff = DateTimeDiff(dt,Ref(dt,-1));
if ( dt_diff[BarCount-1] == 5 AND Interval() == 5 ) {
	Title = "Is 5-seconds Interval and 5s data.";
}

---

@alligator

MDTN = Lowest(ValueWhen(DTN > 0, DTN));
dbi = LastValue(MDTN);

ValueWhen is costly. Lowest() requests all bars. LastValue disables QuickAFL too.
So overall too costly just to check data interval.

[alligator]

i know but your formula doesn't work if some bars are missing: dt_diff could be different from the database interval. Also it doesn't work when used with volumes interval, so the only workaround i found was to check all non-zero differences.

[fxshrat]

@alligator

i know but your formula doesn't work if some bars are missing: dt_diff could be different from the database interval.

LowestSince(is_firstvisiblebar) should be better than Lowest.

dt = DateTime();
dt_diff = DateTimeDiff(dt,Ref(dt,-1));
dt_diff = LowestSince(NOT Status("barvisible"), dt_diff);
if ( dt_diff[BarCount-1] == 5 AND Interval() == 5 ) {
	Title = "Is 5-seconds Interval and 5s data.";
}

@alligator

Also it doesn't work when used with volumes interval,

He does not need volume interval but 5 sec interval.

@PeterD

I have a chart layout that includes a 5-second chart

[Tomasz]

@fxshrat

ValueWhen is costly.

Well, not that much. You should not see difference between ValueWhen and other array functions. As to original poster question, I will simply add that to Status() function.
In next version you will simply write:

Status("baseinterval");

[alligator]

Out of curiosity after @fxshrat answer I benchmarked both formulas (repeating them 100 times in a loop) and indeed I couldn't find a significant difference, maybe a fraction of ms.
@Tomasz Could you take into account/distinguish tick databases too ? Thanks a lot.

[fxshrat]

@alligator

Out of curiosity after @fxshrat answer I benchmarked both formulas (repeating them 100 times in a loop) and indeed I couldn't find a significant difference, maybe a fraction of ms.

He was talking about ValueWhen.

Lowest() does request all bars. So there IS a difference if there is much data (bars).
Eg. I checked on >100k bars and it is around 100 times slower then.

[PeterD]

Wow, you guys are THE BEST!!!

Not only do I have a solution for now, but TJ is making a change to AB for me!

And I learned a few things about what affects execution speed, too. Thanks!

This is why I use AB and participate on this forum, it's because of the fantastic support like this.