Paul/Graham, have tried both suggestions and I cannot get it to work.
Let me explain in more detail as I did a pretty poor job last time:
:-(
I have a metastock formula for a 21 day initial high entry trigger that
I am trying to convert. In words the logic is:
"If the HIGH of 20 days ago is >= to the highest value in the last 20
periods then use the highest high
else
If the HIGH of 20 periods ago is < highest high in the last 20 periods
then use the prior bars high."
In other words it is looking for 20 days where the all the highs are
lower than the high of 21 days ago. It is looking for the initial high
reversal.
the metastock formula is
IH = Input("Initial High", 1, 300, 21);
HH = IH - 1;
if(Ref(HIGH,-HH)>=HHV(HIGH,HH),HHV(HIGH,HH),if(Ref(HIGH,-HH)<HHV(HIGH,HH),PREV,0));
My attempt at converting this, including Graham's suggestion is as follows:
IH_Periods = Param("Initial High", 21, 10, 100,1);
HH = IH_Periods - 1;
A = Ref(H,-HH); // High of 20 periods ago
B = HHV(H,HH); // Highest High in 20 periods
Z = HHV(H,HH);
PREV = Z;
for(i=1;i<BarCount;i++)
{
if(A[i] < B[i]) PREV[i] = Z[i];
else PREV[i] = Z[i-1]; // PREV is previous value of Z.
}
High_DOTS = IIf(A >= B, B, IIf(A < B,prev, 0));
Plot(High_DOTS, " DOTS", colorBlack, 8+16);
Plot(C, "Price", ColorBlack, StyleBars);
The problem is that it (see attachment) bar at A is less than 20 days
(13 days) from Y therefore the dots should have continued at the X level
and not stepped up to the higher value. B (14 days) and C (15 days)
should also be at the X level.
Appreciate the help.
Keith
ps. this is my first attempt at a loop and also converting a Metastock
formula.
Paul Ho wrote:
> you have assign z = 0; the whole z array equal to 0, so z[i -1] is of
> course 0;
> try z[0] = 0 instead and use prev[i] instead of constant PREV.
>
> ------------------------------------------------------------------------
> *From:* [email protected] [mailto:[EMAIL PROTECTED]
> *On Behalf Of *Keith Osborne
> *Sent:* Tuesday, 20 February 2007 2:54 PM
> *To:* [email protected]
> *Subject:* [amibroker] Help with coding PREV alternative
>
> Hi, I am attempting to convert a Metastock formula with a PREV
> statement. I have read a number of messages in Amibroker database and my
> attempt is as follows.
>
> IH_Periods = Param("Initial High", 21, 10, 100,1);
>
> HH = IH_Periods - 1;
>
> Z = HHV(H,HH);
> Z = 0; // Initialize
> for(i=1;i<BarCount;i++)
> {
> PREV = Z[i-1]; // PREV is previous value of Z.
> }
>
> When I use PREV in a AB formula such as iif(A > B, XX, PREV) I get 0
> (Zero) when A<B.......rather than the previous value of Z. Can I assign
> a HHV to Z?)
>
> I hope I have explained this.
>
> Any help would be appreciated.
>
> TIA .... Keith
>
>
