Error I'm not sure about: negative_or_zero_param

• 02/06/2020 at 2:39 AM #118794
  Finning

  Hi there,

  not sure about the following error. What does this mean?

  “server.strategy.probacktest.error.negative_or_zero_param”

  Please see attached.

  Thanks,

  Finning

  

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  02/06/2020 at 9:33 AM #118801
  Nicolas

  Prorealtime is in the process of deploying new functionalities concerning the details of error messages. Some technical codes have not yet received their translations in “clear” language, this is why it seems incomprehensible.
  But I can tell you that it refers to the old message indicating that there is an indicator period of 0 or negative, quite simply 🙂

  

  Nicolas

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  02/09/2020 at 8:14 AM #119078
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  Hi Nicolas,

  “an indicator period of 0 or negative” – what does this mean? How can this error come about?

  I know it seems self explanatory as to what the problem is, I just can’t seem to find what is causing the problem.

  E.g. – if you have a cancelling function, like x=x to get rid of/nullify an unwanted variable from a call function, can this cause the problem?

  If I have DEFPARAM Preloadbars = 10000 as well, is this related to the problem?

  I don’t have a problem in backtests, only running live.

  Thanks,

  Finning.

  

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  02/09/2020 at 9:03 AM #119080
  Vonasi

  Finning wrote:

  if you have a cancelling function, like x=x to get rid of/nullify an unwanted variable from a call function

  Why don’t you just replace the variable with IGNORED in the CALL instruction?

  

  Vonasi

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  02/09/2020 at 5:45 PM #119099
  Nicolas

  This problem is quite common if one of your period of calculation for an indicator is not valid.

  In any case, you can get rid of this error with this kind of coding:

  myindi = average[max(1,period)]

  1	myindi = average[max(1,period)]

  We make sure that the period is superior or equal to 1.

  

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  02/10/2020 at 11:48 PM #119259
  Finning

  Hi Nicolas and Vonasi,

  thanks for your replies. I have replaced unwanted CALL variables with ignored.

  It also looks like the problem that I’m getting is from the B.M.I  Angle indicator – have attached a code of what I’m running for it below. Also, am running the period and the lookback as the same number for this. Am running a code without this indicator and it doesn’t have a problem.

  Is there any reason why I don’t get this error during backtesting – only during live trading? Trades enter for one bar then the system stops. Would be a lot easier to find if I could backtest for the error.

  And Nicolas, with the code you wrote above – the

  myindi = average[max(1,period)]

  1	myindi = average[max(1,period)]

  What happens if I want Period to = 120 (it should be a fixed value anyway). If for some reason Period doesn’t equal 120, does that mean it would revert back to 1, and would that mean it would then throw out my average from 120 down to 1?

   

  B.M.I code I’m using is below.

  // --- settings //Period = 10 //Moving Average Period //lookback= 20 // Number of candlesticks back on which the slope is evaluated // --- end of settings MM = Exponentialaverage[Period](close) //pente = (MM-MM[lookback])/lookback //trigger = Exponentialaverage[Period](pente) ADJASUROPPO = ((MM-MM[lookback])/pipsize) / lookback ANGLE = (ATAN(ADJASUROPPO)) if angle>0 then r=0 g=255 else r=255 g=0 endif RETURN angle coloured(r,g,0) style(histogram) as "Angle", 0 as "level 0"

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  // --- settings //Period = 10  //Moving Average Period //lookback= 20 // Number of candlesticks back on which the slope is evaluated // --- end of settings   MM = Exponentialaverage[Period](close) //pente = (MM-MM[lookback])/lookback //trigger = Exponentialaverage[Period](pente) ADJASUROPPO = ((MM-MM[lookback])/pipsize) / lookback ANGLE = (ATAN(ADJASUROPPO)) if angle>0 then r=0 g=255 else r=255 g=0 endif   RETURN angle coloured(r,g,0) style(histogram) as "Angle", 0 as "level 0"

  Thanks,

   

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  02/11/2020 at 12:07 AM #119260
  robertogozzi

  Nicolas’ code means that PERIOD cannot be < 1 (which would be reported as an error by PRT), there’s no upper limit.

  To set both lower and upper limits to, say, 1-999 you should write:

  myindi = average[max(1,min(999,period))] //any value in between is fine

  1	myindi = average[max(1,min(999,period))]    //any value in between is fine

   

  

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  02/11/2020 at 7:33 AM #119264
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  Hi Roberto,

  I had another system stop on me today, after I tried to implement the change that you mentioned above.

  The system backtested ok no problems, got the system running, then the same error led to system shutdown. Again, the system was in the market for 1 bar, then quit with an error at the end of that bar.

  The code that I used is below – are there any problems with it? This is taken from the code version on the autotrading popup of running codes from the system that had the error today.

  MM = Exponentialaverage[max(1,min(period,period))](close) //pente = (MM-MM[lookback])/lookback //trigger = Exponentialaverage[Period](pente) ADJASUROPPO = ((MM-MM[max(1,min(lookback,lookback))])/pipsize) / (max(1,min(lookback,lookback))) ANGLE = (ATAN(ADJASUROPPO)) if angle>0 then r=0 g=255 else r=255 g=0 endif RETURN angle coloured(r,g,0) style(histogram) as "Angle", 0 as "level 0"

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  MM = Exponentialaverage[max(1,min(period,period))](close) //pente = (MM-MM[lookback])/lookback //trigger = Exponentialaverage[Period](pente) ADJASUROPPO = ((MM-MM[max(1,min(lookback,lookback))])/pipsize) / (max(1,min(lookback,lookback))) ANGLE = (ATAN(ADJASUROPPO)) if angle>0 then r=0 g=255 else r=255 g=0 endif     RETURN angle coloured(r,g,0) style(histogram) as "Angle", 0 as "level 0"

  The only other thing that I can see that is different between some code i have that is error free and code that is giving me errors is per below.

  ha = highest[barindex](account) if account < ha*0.9 then sell at market exitshort at market quit endif

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  ha = highest[barindex](account)   if account < ha*0.9 then sell at market exitshort at market quit endif

  I understand the concept stated above that period cannot be <1 – though – that said – I have numerous examples from working live trading code where [0] is used – below is an example:

  Upper = HIGHEST[a](CLOSE[0])

  1	Upper = HIGHEST[a](CLOSE[0])

   

  

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  02/11/2020 at 9:33 AM #119285
  robertogozzi

  [0] with system constants or variables is normal it’s like no brackets CLOSE and CLOSE[0] both return the same price.

  [a] does not accept that “a” be < 1.

  The indicator works finely.

  Use GRAPH in your strategy to debug it.

  

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  02/11/2020 at 9:37 AM #119287
  Finning

  Hi Roberto,

  what am I looking to GRAPH?

  As you said, the indicator works well, and I get a full backtest  over the data I load without a problem.

  

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  02/11/2020 at 9:45 AM #119291
  Nicolas

  First Barindex is equal to 0, so the system can make an highest of 0 period as we said since posts..

  ha = highest[max(1,barindex)](account)

  1	ha = highest[max(1,barindex)](account)

  Finning wrote:

  I have numerous examples from working live trading code where [0] is used – below is an example:

  As Roberto said, Close[0] this is a constant, not an indicator with a period in bracket.. The number is the offset in the past of the Close constant. I suggest you have a look to the course for beginners in programming: https://www.prorealcode.com/courses/training-program-introduction-programming-prorealtime/

  1 user thanked author for this post.

  sartorir

  

  Nicolas

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  02/11/2020 at 10:01 AM #119293
  robertogozzi

  If you change your code above in:

  ha = highest[barindex](account) if account < ha*0.9 then sell at market exitshort at market quit endif GRAPH ha GRAPH account GRAPH barindex

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  ha = highest[barindex](account) if account < ha*0.9 then sell at market exitshort at market quit endif GRAPH ha GRAPH account GRAPH barindex

  when backtesting you will be able to watch, for each candlestick where the mouse is sitting, in a special “variable” window the values those GRAPHed variables retain.

  This will help you detect any incorrect value that you might want to change.

  You can add many more GRAPH instructions on demo account (only 5 of them on real IG accounts).

  See attached pic.

   

   

  

  robertogozzi

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  02/12/2020 at 10:28 AM #119393
  Finning

  Hi Nicolas/Roberto,

  thanks for your help with this. That solved the problem.

  Cheers

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