Hi, You are getting the errors because you have settings saying to use Long and Short, yet no code on how to handle the shorts.
Change the setting to Long only and your problem will go away. Alternatively, you will need to include code setting Short/Cover to 0 such that no shorts are ever taken, despite the setting saying that they are handled. It is not true that you only have two actions in the market. Selling to exit a position is very different than selling to enter a position. Same applies for buying to enter vs. exit. The reality is that in the market you have four actions; enter/exit long and enter/exit short. AmiBroker calls the former Buy/Sell and the latter Short/Cover. Rules can be written for each of the four actions, along with their associated BuyPrice, SellPrice, ShortPrice and CoverPrice. The original author's intent is clear by virtue of which arrays he has chosen (i.e. Buy/Sell) which is exactly why four arrays are required and should clearly illustrates why there is not any redundancy. Mike --- In [email protected], Michael <comtech....@...> wrote: > > Hi Mike, > > Thanks so much for your help. > > However, I am using both "long and short", > > and I think two of the 4 variables are redundant. > > In the market, you only have two actions, either buy or sell. > > Short is a form of sell, and cover is a form of buy. > > I don't understand why AB differentiate them? > > In the example code below: > > > Buy = state>Ref(state,-1); > > Sell = state<Ref(state,-1); > > How do I know the intent of the author originally was to set "Short =0, and > Cover=0"? > > On Tue, Mar 9, 2010 at 12:27 AM, Mike <sfclimb...@...> wrote: > > > > > > > Hi, > > > > You need to set the Automatic Analysis window settings to match your script > > for Long Only vs. Short Only vs. Both. > > > > http://www.amibroker.com/guide/h_backtest.html > > > > Alternatively, you could do it in code by setting Short and Cover to to > > zero. Do not assign non zero values if you don't actually want to take any > > short trades! > > > > Mike > > > > > > --- In [email protected] <amibroker%40yahoogroups.com>, Michael > > <comtech.usa@> wrote: > > > > > > I got some old code from other friends, and even for the example in the > > > "sample systems" from AB, > > > > > > I got the same error: > > > > > > And it's like "Missing short/cover variables..." > > > > > > The code is like this: > > > > > > Buy = state>Ref(state,-1); > > > Sell = state<Ref(state,-1); > > > > > > -------------- > > > > > > To get around the error message, I added, > > > > > > Buy = state>Ref(state,-1); > > > Sell = state<Ref(state,-1); > > > Short = Sell; > > > Cover = Buy; > > > > > > Is that a right thing to do? > > > > > > Thanks a lot! > > > > > > > > > >
