Subject: plot2d failed to plot too many discrete points
From: Robert Dodier
Date: Sun, 13 May 2012 23:54:03 +0000 (UTC)
On 2012-05-13, Raymond Toy <toy.raymond at gmail.com> wrote:
>> To the developers: is there any reason to prefer COPY-TREE to COPY-LIST
>> in src/plot.lisp?
>
> Maybe because it's not a list but a tree (or a list of lists)? I didn't
> look closely to see if that matters or not.
I think sometimes it's just a list and sometimes it's a more complex
expression. COPY-TREE is now called to prevent the plotting functions
from changing the original data. I don't know if COPY-LIST is
sufficient for that purpose.
> I'm sure the sbcl folks would fix such a bug very quickly.
Reported as: https://bugs.launchpad.net/sbcl/+bug/998926
> I know sbcl and cmucl have fairly slow float printers because both try
> pretty hard to make sure the output is printed in a way that when read
> in the same number results.
Well, it's entirely reasonable to preserve readability for floats, but
it does make it less convenient to process a sizeable data set ... I can
see a couple of things that would make it faster. (1) Gnuplot could read
binary data so no printing & parsing is needed. (2) Maybe scanf or
whatever is Gnuplot's number parser could recognize the bytes of a float
encoded as hexadecimal. E.g. #f4DEADBEEF => some number. Or maybe
#f8(mantissa,scale,sign) since those fields are conveniently returned by
INTEGER-DECODE-FLOAT.
(1) and (2) aren't human-readable (for most humans I guess) but it could
make machine-to-machine communication faster and unambiguous. Yes, I am
daydreaming here.
best
Robert Dodier