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Excellent. Thank you Tomasz!
--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>
> Hello,
>
> "Release Notes" document, changes for version 4.46:
>
> Numbers (floats) are now automatically 'upsized' to arrays on first use of l-value array subscript operator without causing error.
> Also r-value subscript can be applied to numbers and return the number itself without causing error, but the underlying variable
> remains just a single number.
>
> This allows to easily intialize arrays to any value without need to write loops.
>
> Example 1:
> in previous versions you would need to write:
>
> for( i = 0; i < BarCount; i++ ) myarray[ i ] = 0 ; // fill with zeros
> myarray[ 5 ] = 6; // write value to 5th element of the array
>
> now you can write simply:
>
> myarray = 3; // initialize, at this moment myarray is just a number
> myarray[ 5 ] = 6; // write value to 5th element of the array, the variable is automatically
> // upsized to array and all elements are filled with a numeric value
> // that was originally placed in myarray variable
>
> /* myarray is holds now the array filled with values of 3 except element 5 that has value of 6 */
>
> mynumber = 5;
> test = mynumber[ 7 ]; // previous versions would give an error message here
> // now subscript operator for r-value numeric variable
> // is allowed and returns just the number
> // and variable is not upsized to array unless appears on left side
> // of assignment (l-value)
> /* mynumber variable here is still a number */
> WriteVal( test );
>
> Best regards,
> Tomasz Janeczko
> amibroker.com
> ----- Original Message -----
> From: "progster01" <progster@xxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Tuesday, March 10, 2009 7:26 PM
> Subject: [amibroker] Re: probable bug in afl execution
>
>
> > Alex - thanks much for your follow-up post.
> >
> >>Indeed, after the initialization, the type is number; however, when >the first indexed access is made, the type is switched to
> >>array
> >
> > I am so not used to this sort of thing!
> > (It's probably documented somewhere - can anyone note where?)
> >
> >>now it works! no inconsistency is detected.
> >
> > I'm glad you are able to move on, but if you don't understand the reason(s) for the initial behavior and subsequent change,
> > beware! <g>
> >
> >
> > --- In amibroker@xxxxxxxxxxxxxxx, "redberryys" <redberryys@> wrote:
> >>
> >> Hi progster,
> >> That is a very good idea - typeof is good to know for debugging.
> >> Indeed, after the initialization, the type is number; however, when the first indexed access is made, the type is switched to
> >> array - if I add the same printf after the loop, I see both as arrays. This also explains why the values printed by printf are
> >> different from bar to bar.
> >>
> >> I've added some code to automatically check for consistency , and - the most intriguing thing - and awkward for me - happened:
> >> now it works! no inconsistency is detected. I did see temporary inconsistencies when the check was not activated, and after the
> >> backtester run. I still think there might be a refresh missing somewhere; also, I did see some weird behavior of the backtester:
> >> if I use my temporary arrays for the entries/exits and only later copy them to the Buy/Sell/Short/Cover used by the backtester,
> >> the backtester seems to get confused - it changes them.
> >> All in all, I still think this would be worth some further investigation, but I'll drop it for now.
> >>
> >> Once again, thank you so much for taking the time to look into this question. Once made to work, I found that for loop to be
> >> useful in reducing whipsaws, and in improving system performance when fixed commissions are applied [by the broker! :)) ]
> >>
> >> For reference, here's the code I used for validation:
> >>
> >> //Plot(inBuySwitch, "IBS", styleLine | styleOwnScale);
> >> inBuySwitch = (vinBuy + Ref(VinBuy,-1) == 1);
> >> inconsistentB = inBuySwitch && !(Buy || Sell);
> >> c_incB = Cum(inconsistentB);
> >> inShortSwitch = (vinShort+ Ref(vinShort,-1) == 1);
> >> inconsistentS = inShortSwitch && !(Short || Cover);
> >> c_incS = Cum(inconsistentS);
> >> printf("inBuySwitch= %g c_incB= %g c_incS= %g\n\n", inBuySwitch, c_incB, c_incS);
> >>
> >> Regards,
> >> Alex
> >>
> >>
> >> --- In amibroker@xxxxxxxxxxxxxxx, "progster01" <progster@> wrote:
> >> >
> >> >
> >> > Hi again.
> >> >
> >> > I think you may be trying to treat as arrays some items whose typeof() is number.
> >> >
> >> > Below is a section of the code with a few extra printf() statements, showing that, for example, nbuy_ is a number, not an
> >> > array.
> >> >
> >> > Despite this, later notation such as:
> >> >
> >> > nbuy_[i] = 1;
> >> >
> >> > is silently accepted.
> >> >
> >> > I think that to get the results you want may require very careful attention to types, and possibly a different idiom than you
> >> > are using.
> >> >
> >> > There may be little help in that generalization, but I've not personally written/tested AFL ala your example, so I don't have a
> >> > ready-made "solution" available to offer. (Others might.)
> >> >
> >> > -----------
> >> >
> >> > //filter the raw signals
> >> > nBuy_ = nSell_ = nShort_ = nCover_ = 0; // make sure all arrays are set empty
> >> >
> >> > printf( "\ntypeof(nBuy_): " + typeof(nBuy_) ) ;
> >> > printf( "\ntypeof(Buy_): " + typeof(Buy_) ) ;
> >> >
> >> >
> >> > printf( "\nAfter initialization: \n" ) ;
> >> > printf( "nBuy_= %g nSell_= %g\n", nBuy_, nSell_ );
> >> > printf( "nShort_ = %g nCover_= %g\n", nShort_, nCover_ );
> >> >
> >> >
> >> > inBuy = inShort = 0;
> >> > vinBuy = vinShort = 0;
> >> > eprice = 0; //
> >> > veprice = 0; //
> >> > branch = 0;
> >> >
> >> > printf( "\ntypeof(inBuy): " + typeof(inBuy) ) ;
> >> > printf( "\ntypeof(branch): " + typeof(branch) ) ;
> >> >
> >> >
> >> >
> >> > --- In amibroker@xxxxxxxxxxxxxxx, "redberryys" <redberryys@> wrote:
> >> > >
> >> > > Hi progster,
> >> > > Thank you for your response. I've tried it and it still does the same thing. I shou[[etc - removed ]
> >>
> >
> >
> >
> >
> > ------------------------------------
> >
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> >
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> >
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> >
> > Yahoo! Groups Links
> >
> >
> >
>
------------------------------------
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