Re: Plotting double precision

[Craig Markwardt <craigmnet(at)cow.physics.wisc.edu>]

davidf@dfanning.com (David Fanning) writes:
> Investigate some of the keywords
> that are available for the PLOT command. I would start with
> [XYZ]Tickname, [XYZ]TickV, and maybe [XYZ]Tickformat.

Yeah, and welcome to another planet of hurt.  David is right though.
The best solution is to scale your data and then label the axes
yourself.  Personally, I think it's actually cleaner to scale your
data by 10^(-39), and then put that in the "units" of your x/ytitle.

I've also encountered the single-precision-plotting problem when I am
plotting numbers with X = X0*(1+d) where d is very small.  When d/X0
becomes smaller than about 1 in a million, you can see a noticeable
staircase effect on the plot, since single precision can't preserve
the fidelity.  My only solution has been to subtract and rescale the
data.

Craig

-- 
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Craig B. Markwardt, Ph.D.         EMAIL:    craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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