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Hi Tomasz!
Thank you very much! Great job!
These new functions are extremely useful, especialy for coding of the
trading systems. I've made my huge AFL files 10-15% smaller (and
found one bug :-) replacing my proprietary code by your new methods!
I have one minor request. Right now AmiBroker AFL help lists AFL
methods by versions. It's inconvenient a bit. Is it possible to merge
them all together?
Thank you,
Dima.
--- In amibroker@xxxx, "Tomasz Janeczko" <tj@xxxx> wrote:
> Hello,
>
> The next issue of the newsletter will cover all new functions in
AFL but
> let me now explain shortly a couple of them:
>
> NOTE: all these functions are available ONLY in v 3.52 (and above :-
))
> =====================================================
>
> StrLen( String ) function
> ====================
> - calculates the length of the string.
> This function could be used for (for example) filtering out only 3
letter stock codes:
>
> buy = something AND strlen( name() ) == 3;
>
>
> AMA( Array, SmoothingFactor ) function
> =============================
> - calculates adaptive moving average - simliar to EMA but
> smoothing factor could be time-variable (array).
> The example of volatility-weighted adaptive moving average formula:
>
> graph0 = ema( close, 15 );
> fast = 2/(2+1);
> slow = 2/(30+1);
> dir=abs(close-ref(close,-10));
> vol=sum(abs(close-ref(close,-1)),10);
> ER=dir/vol;
> sc =( ER*(fast-slow)+slow)^2;
>
> graph0 = ama( close, sc );
>
>
> Study( StudyID, ChartID = 1 ) function
> =======================
> - generates an array equivalent to a trendline study drawn
> by the user - allows detecting trendline breakouts from AFL
> - more details will be given in a newsletter
>
>
> ExRem( Array1, Array2 ) function
> ========================
> - removes excessive signals:
> returns 1 on the first occurence of "true" signal in Array1
> then returns 0 until Array2 is true even if there are "true"
signals in Array1
>
> Example:
> buy = ExRem( buy, sell );
> sell = ExRem( sell, buy );
>
>
> Flip( Array1, Array2 ) function
> ======================
> - works as a flip/flop device (electronic/electric engineers will
know what I mean)
> - returns 1 from the first occurence of "true" signal in Array1
> until a "true" occurs in Array2 which resets the state back to zero
> unil next "true" is detected in Array1...
>
> IsEmpty( Array ) function
> ===================
> - returns 1 (or 'true') when given point in array is {empty}
> Note: {empty} value is used internaly by AFL to mark
> bars when the value is not available - for example for the first
> 20 bars the value of 20-day simple moving average is not available
> ({empty})
>
>
> IsTrue( Array ) function
> ==================
> returns 1 (or 'true') when given point is not {empty} AND not zero
>
>
> Foreign( Ticker, DataField )
> =====================
> - allows referencing other (than current) tickers in the AFL
formulas.
> Allowable data
fields: "open", "close", "high", "low", "volume", "interest"
> Provides an easy way to implement overlays, as shown in the
> following code:
>
> /* Red line - current security price */
> /* Blue line -overlaid index chart (scaled to fit) */
>
> graph0 = close;
> graph1 = foreign( "XAO", "Close" ) ;
> /* replace "XAO" by your index, or any other ticker to graph along
with you stock */
>
> graph1 = lastvalue( highest( graph0 ) )/ lastvalue( highest(
graph1 ) ) * graph1;
>
>
>
> Best regards,
> Tomasz Janeczko
> ===============
> AmiBroker - the comprehensive share manager.
> http://www.amibroker.com
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