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Max,
It doesn't sound intuitive until you think about how bars are created. All
bars, even tick bars, are bound by time. For instance, a 100-tick bar will
have a start and an end time, based on when the bar is created and finished.
When you combine time-based charts (minute, hour, day, week, etc), the
program is able to align times so that multiple data series can be placed
on a single chart. With tick bars, no such alignment is possible because
there is no guarantee that ticks will line up with anything. In fact, it
would be unusual if they did.
What you're asking for is extremely non-trivial to implement, which is why
commercial packages don't support it. Even trading programming packages,
such as SmartQuant, don't support it.
I've tried my hand at a custom implementation, and managed to achieve
support at the data level. It requires that one data series become the
"master", and defines the time slicing. In my case, I was looking at at
100-ticks of the E-mini, and creating a slice of the $TICK, which may have
been 34 ticks (or some other arbitrary number). Now both series will be
aligned so that charting is possible. You'd have to do something similar to
support aggregation of buyers and sellers for every tick bar. It requires
the equivalent of re-writing the global-server so that it can serve and mix
time-and-sales information on the fly for any chart ... meaning that no
data caching is possible.
I didn't carry the implementation through to charting. I just don't believe
it's worth the special effort (and it is a LOT of effort).
Kevin
At 03:34 PM 1/17/2004 -0800, you wrote:
I have a tick chart, based on last data for
Intel. I want to look at the Buyers vs. Sellers
Activity Bar which requires ask and bid data as
Data2 and Data3. When I try to add those I get an
error message "Tick charts may not be mixed with
other charts or activity bars". The Activity bar
seems to call for the other data but I can't put
it in a chart. What is up with that??
Max
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