I guess, sum() is behaving the ideal way :), The most important thing here is, AMIBROKER being an array processing language, calculates all the elements of array , but at any given active bar, it fetches the current value from the whole arry index and shows it to us,Presumably using some barindex kind of mechanism internally.
When we put close, open or any array in any afl , like ((close + open + High + Low )/4= MAVG),amibroker produces output based on the current value of that array, we dont need to specify current index of that array (scalar value) to get output at any current bar,it manages it intenally. Here its impotant to not that, its IRRELEVANT if we use array in a Function or simply put it in any statement in afl, it fetches a scalar value out of that produced array to show it to us. when I put SUm(close,Barssince()) It ideally fetches the current element of BarsSince array and place it over ther. This is the ideal way. Sum() is behaving the IDEAL way. infact every other function, let it be , MA(Close,BarsSince(TimeNum() < 093000)); or any other function, having Periods, as a second argument. While in Stdev(),it simply goes against the normal behaviour. it should infact, in MUST , point to the current active element of the Barssince(), let it be a 0 or any other value, its irrelevant, its still a scalar. and it simply doesnt do that!. i think i have made my point clear now. Wave : Lastvalue() will surely fetch the last element of the array, but i cant use it while testing it offline, i will get all future values of that array, its all fine if i have to use it while online updation. Regards... --- In [email protected], "wavemechanic" <olesmi...@...> wrote: > > I'm fairly sure that the only way you will get StDev() to accept BarsSince() > in the 2nd argument without complaining is to force the return of a number by > use of LastValue() or SelectedValue(). I don't know why Sum() is not > complaining when BarsSince() is used. > > In the Sum() case, I think that BarsSince( TimeNum ... ) is returning a > constant array based on the bar you select, including the last bar if no bar > is selected. If so, that would work OK but does not explain why StDev() does > not work. > > For Sum(), if you replace TimeNum() with another array generator, for > example, MA( C, 13 ) == ...., Sum() still does not complain but BarsSince() > returns 0 (I believe) and, hence, Sum() is 0. > > You might have stumbled onto a unique situation but I would not assume that > it can be generalized and would always go for ensuring the return of a number > from the 2nd argument whether or not the above is correct. > > Bill > ----- Original Message ----- > From: aaryan111 > To: [email protected] > Sent: July 14, 2010 3:08 PM > Subject: [amibroker] Re: Sum and Stdev , wierd behaviour of stdev > > > Hi , thanx for the feedback wave. > its Syntax is basically to put Period as 2nd argument. > When u put an array in SUM() as 2nd argument, it will take the > corresponding scalar frm that array and apply it as a filter. > > i have successfully executed this > > Sum(Close,BarsSince(TimeNum()>092400)); > > regards > > > --- In [email protected], "wavemechanic" <olesmithy@> wrote: > > > > Neither takes array as 2nd. See syntax in Users Guide. > > ----- Original Message ----- > > From: aaryan111 > > To: [email protected] > > Sent: July 12, 2010 3:41 PM > > Subject: [amibroker] Sum and Stdev , wierd behaviour of stdev > > > > > > Hi Everybody, > > > > Both Sum() and Stdev() Functions Have same Arguments Structure.but when > i put > > Sum(Close,BarsSince(TimeNum()>092400)) > > it executes successfully,while > > Stdev(Close,BarsSince(TimeNum()>092400)) > > gives a warning " Function Expects Different type of argument here " . > > > > as far as i understand , both can take array as 2nd argument and > amibroker will automatically fetch the current running index value of that > array as the 2nd argument, same as it does with other functions. > > > > one can put any other function returning array like barindex() in 2nd > argument , result will be same. > > > > Any suggestions?? > > > > Regards, > > > > > > > > ------------------------------------ > > > > **** IMPORTANT PLEASE READ **** > > This group is for the discussion between users only. > > This is *NOT* technical support channel. > > > > TO GET TECHNICAL SUPPORT send an e-mail directly to > > SUPPORT {at} amibroker.com > > > > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at > > http://www.amibroker.com/feedback/ > > (submissions sent via other channels won't be considered) > > > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > > http://www.amibroker.com/devlog/ > > > > Yahoo! Groups Links > > > > > > > ------------------------------------ > > **** IMPORTANT PLEASE READ **** > This group is for the discussion between users only. > This is *NOT* technical support channel. > > TO GET TECHNICAL SUPPORT send an e-mail directly to > SUPPORT {at} amibroker.com > > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at > http://www.amibroker.com/feedback/ > (submissions sent via other channels won't be considered) > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > http://www.amibroker.com/devlog/ > > Yahoo! Groups Links >
