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Alex & Gabriel,
Saturday, November 22, 2003, 1:55:29 AM, you wrote:
AM> Gabriel,
AM> No code to offer, only advice.
>>Does anyone know the correct way to create an indicator that draws trend
>>lines into the future. I use lt_new to create the trend line and that
>>works fine, but tl_setextright only works sporadically. Sometimes when a
>>new trend line is created, the old one is no longer extended.
AM> I believe the old trendline doesn't get extended if the bars that
AM> defined it scroll off the display. One way to get around this is
AM> to keep track of all the trendline IDs, and on each new bar, read
AM> the TL value at that bar and then set a new trendline endpoint
AM> (TL_SetEnd I think) at that value. That way the value defining a
AM> trendline will always be on the display.
>>I wanted to quantify trend lines, but maybe it is better to calculate
>>the slope and keep track of the values through arrays. Any advice will
>>be appreciated.
Have had success with capturing required values in arrays and
using one TL_New for all but the last line(or set of) with
TL_SetExtRight=False, and another TL_New for the last line with
TL_SetExtRight=True. Use a while loop to limit the plotting to
the last values in the array or all those before it.
Alex, I can scroll the bar holding the righthand values off the
screen; it still plots?
AM> You can do that, but if you calculate your own trendlines, make sure
AM> you do it on log(price) instead of price. Usually tradestation
AM> displays price charts in log scale (as it should), which means that
AM> the trendlines, slopes, and extensions are actually being calculated
AM> on log prices. Any new price read off the trendline is actually the
AM> ExpValue of the internal trendline value.
Find this confusing Alex. If "you calculate your own trendlines"
(with values stored in arrays ?) then why use log ? Raw price
(which presumably the array values have been produced from) is in
itself not log. ie when charting the plots will be appropriate to
scaling. The TL_new 's descrided above plot appropriate to scaling.
Can you explain anymore? I've lost the picture somewhere.
--
Best regards,
jon mailto:jonmac@xxxxxxxxxxx
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