At 01:26 PM 31 10 00 -0500, you wrote:
>As for the sampling of the outcome from a math expression, our (perhaps
>weak) logic was that your user has forced the displayed sample rate as they
>want it, so we use this.
Ian,
That may have been your logic but that isn't the outcome. As I showed in my message,
the output sample rate is the highest of the displayed rate or ANY of the channels
mentioned in the equation, including the output channel (whose contents are being
discarded, so who cares what they were sampled at!)
I propose that the outcome should be at the same rate as the highest sample rate on
the right side of the equation. That is predictable and understandable. The way it
exists now, I can get a different result from the same equation depending on what
channels I'm displaying. I think that is unacceptable.
Another point, until very recently controlling the displayed sample rate was almost
impossible, so I don't think anyone is depending on that behavior.
On the other question, regarding dummies, I have to admit that you are (probably)
right. If the outcome was always dummy when dummies are involved, we couldn't test for
dummies! The problem I guess is that if x==2 and x==dummy are doing the same thing,
comparing x to a number, while dummy, although it is stored as a number in the
database really represents the absence of a number, or NAN (not a number), requiring
special logic. When I say "if X < 2" the assumption is that x is, in fact, a number.
When x isn't a valid number (ie dummy) the question doesn't make sense anymore, so
that the result can't be either true or false, it's undefined! In this case, though,
Geosoft has adopted the convention that dummy is a number and as long as we are all
aware of that we can work around it.
cheers
Marc Pelletier
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