All, I am aligned to Hermans approach - what you guys are talking about seems rather complex to me - the end result doesn't allow for a KISS approach, which is what I like - I agree with H on the time limitation and how "inline metrics" offer us RT system feedback plus we are free to do some extra things there that we can't do under the constraints of the BT (no offence to AB - the constraints are there for a good reason and we all want to use the BT at some time or another).
I am optimistic about the path I am going down with RT portfolio emulation (as I discussed a little bit before under "Inline Backtester" etc. I have been playing with it a little (weekends only) and I believe I can get code to: - emulate a balanced portfolio - integrate multiple systems into that portfolio (including long/short) So far my approach is very basic but I have to start somewhere. (I will post some basic code examples if I get them to work OK) Theoretically I have the base code for multiple systems working but the practical limitation might be scaling up to many symbols (so far I am looping from a watchlist of 3 tickers and the Help manual says this is very slow in RT - still it is better to get it working in theory first and worry about large scale application later). I guess I didn't sell any of you on the idea so far: - our rule based systems are like number generators (not random but slightly biased - hopefully) - trade series are generated when we present data to our systems - over sufficient samples the trade series has a distinctive profile (frequency distribution) - the distribution is tight if our rules are tight - the order of the trades is 'random' OR at the least not under our control ??? So what we have is a series of trades, whose range is limited (by rule) but whose order varies (according to the whim of the market). THE TRADE SERIES PROFILE DOES NOT VARY (IF WE HAVE DESIGNED OUR SYSTEMS WELL) Nominally, the system can produce many different eq curves - based on the order of the series (note that the above is a nominal model - perhaps not an exact model - of the real world of trading but it is close enough to enable us to make trading predictions). HOWEVER, ONCE WE START TO ALLOCATE CAPITAL TO THE SYSTEM, IN VARYING AMOUNTS AND AT DIFFERENT TIME INTERVALS, THE NUMBER OF POSSIBLE EQ CURVE OUTCOMES ESCALATES. This allocation of capital, is done by the BT in ways that take quite a bit of effort to follow (I am not saying that the BT has any faults only that Portfolio Backtesting can obscure the real UNDERLYING performance of the system). Further to that, the BT doesn't allow multiple system analysis, at a Portfolio level. THE FACT IS THAT THE TRADE SERIES CARRYS (MATHEMATICALLY) ALL OF THE INFORMATION ABOUT THE SYSTEM THAT WE NEED - WITHOUT HAVING TO SUBMIT IT TO THE BT. In short: the trade series, expressed as growth factor, can be used to emulate different portfolio outcomes, after the fact i.e. IT IS EASIER TO UNDERSTAND THE PORTFOLIO RAMIFICATIONS IF YOU GET THE TRADE SERIES FIRST AND THEN TRIAL VARIOUS PORTFOLIO APPROACHES INDEPENDENTLY. Inline metrics (indicators) is one place in AB that lends itself to this - no COM/OLE/CBT?. Portfolio emulation example (for a balanced portfolio): - take the trades as Gf e.g. 3% == 1.03 (in an array) - repeat for several symbols - average the GF, for all symbols, bar by bar, as an array to produce the Portfolio GF - start with any initial eq and multiply by the Portfolio GF >From there we can change capital allocation at any bar if we want to, provided we have the programming skills. So far I have got close to doing the above: - I am not sure if AB limitations OR my limitations will stump me eventually - I am optimistic it can be done - initially, the method is very limited (no scaling in out etc, closed trades only, no multiple trades per symbol) but that might change later Note: I understand it is not a BT, I am not trying to build a BT - I am trying to get the same understanding of my systems that the BT offers but do it in RT and with a lot less code and hand waving. (less sophistication == less code but not necessarily less understanding and usefulness). The only problem I have encountered so far is that what I need to share it with others is more difficult than what I need for myself - so I have to work a bit harder there. The reason behind that is that I have jumped the over the fence to RootCauseEvaluation, which is a mindset, and hence I don't see a need for all of the bells and whistles that BT's provide (all the noise of the whistle blowing jsut distracts my concentration on what really counts). I will share some base code as soon as I can (it is rather simplistic code but it helps to argue my case). RCE - it's not the holy grail of system design and evaluation but it is a different approach that can expand our knowledge somewhat. brian_z --- In [email protected], "Barry Scarborough" <[EMAIL PROTECTED]> wrote: > > I'm not sure what you mean but I often put multiple systems on one > page. I watch how they perform compared to the one I am actually auto > trading. I also add other indicators at times to see if they will add > anything to the logic. > > Barry > > --- In [email protected], Dennis Brown <see3d@> wrote: > > > > Would it work to use multiple virtualized systems on the same > physical > > machine? > > > > Dennis > > > > On Aug 18, 2008, at 10:47 AM, Barry Scarborough wrote: > > > > > I think it is safer to run multiple instances of AB on separate > > > systems. I keep getting mixed or confusing results when I try to > use > > > two instances on one system. I was trying to capture 5 second data > > > and run auto trading on the same system. I opened the auto trading > > > first and then the 5 second. The data in the 5 second instance > gets > > > lost and I can't figure out why. I even tried to save it a few > times > > > during the day. I run it all day and when I looked at it later it > > > isn't there. Well some of it is which is even more confusing, the > > > most recent part. I have the database set to 100,000 bars so I > should > > > be able to capture about a month of data. Ain't working. So I > started > > > collecting the 5 second data on another system. I will see how > that > > > works. If using multiple instances on one system is supposed to > work > > > then someone needs to define the parameters for doing so. > > > > > > Barry > > > > > > --- In [email protected], "Paul Ho" <paul.tsho@> wrote: > > >> > > >> I think the easiest is to run multiple instances of AB, one per > > > system. am i > > >> missing something? > > >> > > >> > > >> _____ > > >> > > >> From: [email protected] > [mailto:[EMAIL PROTECTED] > > > On Behalf > > >> Of Barry Scarborough > > >> Sent: Monday, 18 August 2008 9:46 PM > > >> To: [email protected] > > >> Subject: [amibroker] Re: About Automatic Analysis > > >> > > >> > > >> > > >> Herman he is talking about automatic analysis. How can you run > more > > >> than one formula at a time? AA defines the formula that is being > > >> tested. > > >> > > >> You can test more than one system at a time by "forward > testing". I > > >> put my formula in a specially designed bar replay indicator that > > > will > > >> keep track of the number of positions/shares and the price when > the > > >> trade is made. I run BarReplay and feed 5 second data into the > > >> formula. It tells where the trade is made, the conditions of all > > > the > > >> indicators at the trade, whatever the designer wants to track, > and > > >> the price at the trade. I calculate the gain as each trade is > > > closed. > > >> I post all of that in the interpretation window. Then you can > click > > >> on each formula and see what the stats are. I also dump this data > > >> into _Trace so that I can go back later and focus in on a > specific > > >> area using DebugView when it doesn't trade as expected. Tracing > > > more > > >> than one formula is a pain and I typically use this for debug > only. > > >> > > >> If you want to check longer periods you can capture hour or 15 > > > minute > > >> data and feed that into a EOD chart or weekly chart to see what > is > > >> going on in them. The shorter the period you feed into your > formula > > >> the more accurate the results. Let your imagination run away and > > > you > > >> can test/tweak almost anything this way. > > >> > > >> IMO that is more accurate than back testing since you are > tracking > > >> the almost true performance of the system. Anyway, that is how I > > >> handle multiple formula analysis at a time. > > >> > > >> Barry > > >> > > > > > > > > > > > > ------------------------------------ > > > > > > Please note that this group is for discussion between users only. > > > > > > To get support from AmiBroker please send an e-mail directly to > > > SUPPORT {at} amibroker.com > > > > > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > > > http://www.amibroker.com/devlog/ > > > > > > For other support material please check also: > > > http://www.amibroker.com/support.html > > > Yahoo! Groups Links > > > > > > > > > > > >
