> // Buy = PlotShapes(shapeUpArrow,colorGreen);
> //
Sell = PlotShapes(shapeDownArrow,colorRed);
Hi,
The
above lines are bad. You are essentially saying to set the Buy
signal to
be equal to the result returned by calling PlotShapes,
which is
meaningless. Same for Sell.
Buy*ShapeupArrow is just an _expression_ that
evaluates to either zero
(Buy = false; i.e. 0) or non zero (Buy = not
false; i.e. not 0).
Usually Buy has been set to a binary value zero
vs. one. So,
Buy*ShapeupArrow usually evaluates to zero or the value of
ShapeupArrow, meaning that we either plot zero (do nothing) or an up
arrow.
However, it is possible for Buy to hold values other than
zero or one
(i.e. any non zero value is still "true"). So be aware of it
before
using a multiplier like that in the plot statements. In your
particular case, Flip returns strictly zeroes and ones into the Buy.
So, you're fine.
Mike
--- In amibroker@xxxxxxxxxps.com,
"brianw468" <wild21@xxx> wrote:
>
> The following simple
program illustrates an intriguing problem I
> encountered when trying
to develop a complicated trading system.
> //Test Program
> fast =
MA(C,15);
> slow = MA(C,50);
> Buy =
Cross(fast,slow);
> Sell = Cross(slow,fast);
> Buy =
Flip(Buy,Sell);
> Sell = Flip(Sell,Buy);
>
Plot(fast,"fast",colorRed);
>
Plot(slow,"slow",colorGreen);
>
PlotShapes(Buy*shapeUpArrow,colorGreen);
>
PlotShapes(Sell*shapeDownArrow,colorRed);
> // Buy =
PlotShapes(shapeUpArrow,colorGreen);
> // Sell =
PlotShapes(shapeDownArrow,colorRed);
>
> When used as
shown, it works as intended. i.e. I get "Up" arrows
for
> each bar
while the fast MA remains above the slow MA, and "Down"
> arrows for
the converse situation. However, if I use the
alternative
> Plot
statements that are shown "commented out", I get Up and Down
> arrows
on ALL bars. Can anyone explain this? I need to resolve this
> before
moving on to bigger and better things as I wish to
use "flip"
>
with arrays other than Buy and Sell.
> Incidentally, I have never found
a reference to
> the "Buy*ShapeupArrow" format in the manual, though
there are many
> examples in the AFL library.
>
>
Brian
>