HELP NEEDED: What's wrong with the PlotShapes in this AFL (William's Third wise Man)

lovehuman · #1 16th July 2008, 09:51 AM

Hi,

I am trying to plot arrows based on Bill William's Third wise man. I am looking for five price bars at a time and comparing High values. If the middle high is higher than previous two highs and next two highs, I want to plot up Arrow symbol. However with the following code, I end up plotting uparrow on every bar (even when value of tmp is false). What am I doing wrong here?

for( i = 3; i < (BarCount-2); i++ )
{
tmp = (High[i] > High[i-1]) AND (High[i-1] > High[i-2]) AND (High[i] > High[i+1]) AND (High[i+1] > High[i+2]);
//_TRACE("tmp : " + tmp);
PlotShapes( IIf( tmp, shapeUpArrow, shapeNone ), colorGreen,0, H,10 );
}

THETRADER · #2 16th July 2008, 03:22 PM

OHLC are all arrays. You dont need to, and, should not use it as array. Just try the following :

tmp = (High > Ref(High,-1)) AND (High > Ref(High,-2)) AND (High > Ref(High,1)) AND (High > Ref(High,2));
PlotShapes( IIf( tmp, shapeUpArrow, shapeNone ), colorGreen,0, H,10 );

lovehuman · #3 18th July 2008, 01:14 AM

Quote:

Originally Posted by THETRADER

OHLC are all arrays. You dont need to, and, should not use it as array. Just try the following :

tmp = (High > Ref(High,-1)) AND (High > Ref(High,-2)) AND (High > Ref(High,1)) AND (High > Ref(High,2));
PlotShapes( IIf( tmp, shapeUpArrow, shapeNone ), colorGreen,0, H,10 );

Thanks a lot "TheTrader". This resolved the issue. Thanks for all your help. I was banging my head from last one week on this

Once again, thank you for helping me!

kkseal · #4 18th July 2008, 02:01 PM

That still doesn't explain why the original code was not working. Think the for loop should have started with i=2, but is that the reason?

aad · #5 18th July 2008, 05:36 PM

Quote:

Originally Posted by kkseal

That still doesn't explain why the original code was not working. Think the for loop should have started with i=2, but is that the reason?

for loop can start with i=2 but the correct code is

_SECTION_BEGIN("William's Third Wise Man");

for( i = 3; i < (BarCount-2); i++ )
{
tmp[i] = (High[i] > High[i-1]) AND (High[i-1] > High[i-2]) AND (High[i] > High[i+1]) AND (High[i+1] > High[i+2]);
}
PlotShapes( IIf( tmp, shapeUpArrow, shapeNone ), colorGreen,0, H,10 );

_SECTION_END();

We need to store value of tmp in an array corresponding to each value of i when we use for loop. Once that is done, we then use PlotShapes() function only once (using capabilities of array in Amibroker).

Best regards,

Abhay

kkseal · #6 18th July 2008, 05:54 PM

Quote:

Originally Posted by aad

for loop can start with i=2 but the correct code is

_SECTION_BEGIN("William's Third Wise Man");

for( i = 3; i < (BarCount-2); i++ )
{
tmp[i] = (High[i] > High[i-1]) AND (High[i-1] > High[i-2]) AND (High[i] > High[i+1]) AND (High[i+1] > High[i+2]);
}
PlotShapes( IIf( tmp, shapeUpArrow, shapeNone ), colorGreen,0, H,10 );

_SECTION_END();

We need to store value of tmp in an array corresponding to each value of i when we use for loop. Once that is done, we then use PlotShapes() function only once (using capabilities of array in Amibroker).

Best regards,

Abhay

Thanks a lot. I too felt 'tmp' was being treated as an array rather than a variable. (Moreover IIF expects an array rather than a variable though it works fine with the reserved ones like 'Buy','Sell').

But shouldn't we be using tmp[i-3] to store the array values correctly in the tmp array?

Or maybe we should simply use IF-ELSE in the original code rather than IIF.
Regards

aad · #7 18th July 2008, 06:38 PM

Quote:

Originally Posted by kkseal

But shouldn't we be using tmp[i-3] to store the array values correctly in the tmp array?

No need. Corresponding to the value i, you will have to store high[i] and tmp[i] in same column only. If you store at tmp[i-3] then you are asking Amibroker to store tmp[i-3] in the column of high[i], which will give wrong results i.e. when the condition for tmp returns 'true', it will be shown at 3 bars prior to actual bar...

Quote:

Or maybe we should simply use IF-ELSE in the original code rather than IIF.
Regards

As you know very well, IIF will be faster than IF-ELSE, although both will function the same.

Regards,

Abhay