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Andrew
> Great. So, to be clear, as long as there is sufficient data loaded prior to
> the start date specified in the date filter, then the TE or TradeSim
> exploration will look for signals immediately at the start date, even if the
> test uses a formula which references a lot of prior bars.
You've got it. To run a Trade Equity test on all data from January 1, 2002 I would estimate the
number of bars at 650 PLUS the N/A period of the code needing the the most history. If this was a
150 day SMA then the exploration would need a minimum of 800 bars.
I assume you're aware that long term exponential moving averages need much more data to get the EMA
"up-to-speed"? An EMA (exponential moving average) needs several times as many data bars as the
specified "periods" value in order to give a value accurate to 3-4 decimal places? For shorter
moving averages a factor of five is realistic, I'm not sure if the same factor is applicable to
longer moving averages. The construction of an exponential moving average means that it uses
fragments of ALL available history, and this can lead to apparent discrepencies between chart and
exploration EMA values when insufficient periods are specified for an exploration.
There are about 30 MetaStock functions that use some form of exponential moving averages (including
Wilders Smoothing) internally. Classic examples are ADX and RSI. So the N/A period is not the only
factor you need to consider for exploration based system tests. I haven't tested the Enhanced System
Tester for the effects of having insufficient data to give accurate indicator values but my
assumption is that it uses the nominal chart "bars loaded" number of bars for bringing indicators
up-to-speed.
Roy
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