| Re: Top 10 for old farts [message #20895 is a reply to message #20847] |
Mon, 31 July 2000 00:00   |
Paul van Delst
Messages: 364
Registered: March 1997
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Senior Member |
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Pavel Romashkin wrote:
>
> Paul van Delst wrote:
>
>> Ahhhhh. When IDL v5 was released, the first thing I did was convert some
>> of my code to use OG. My god was it slow. Also, when I started up
>> Insight I figured that it had to be the showcase of what IDL OG had to
>> offer. That all pretty much turned me off OG - and thus IDL objects - in
>> general. The latter was a bad decision I know, but my "to-do" list kept
>> getting bigger during the 2-week period I spent playing with IDL OG.
>
> I am not arguing about IDLgr* speed with Paul, or, God forbid, David,
> but I find that with today's computers even object graphics is not that
> slow. I don't use multitudes of graphic objects, but rendering a few
> line plots with zoom, point selection, deletion, calculation, adding and
> removing temporary grPlots, etc. - I notice so little difference
> compared with direct graphics that it is not detrimental to the
> application. I think that once faster machines become more widespread,
> 3D object graphics will find more use. On a Pentium 60 w/o OpenGL, I
> agree, it is intolerable.
Maybe for 99% of cases you're right and I fall in the remaining 1%? :o)
The test I applied was to plot what I usually plotted day-to-day with DG
and OG. What I usually plot are high resolution atmospheric radiance
and/or transmittance spectra - sometimes 100,000's points per spectrum,
with, oh, about 40-100 spectra per atmospheric profile. Plotting this
with DG took a long time (seconds) but plotting in OG - well I could go
and answer the call of nature, return and it would still be in the
process. I'm sure part of it is due to the way I put the plotting code
together - remember this was my learning experience - but after a couple
of days I started thinking that one of the main reasons I bought IDL was
so I could type:
PLOT, x, y
and, shazaam! there was my data on screen. With all the programming
required to get a plot with OG - onscreen or on paper - I may as well
buy a F90 graphics library for my system (non-portable, granted) and do
the number crunching AND the plotting in F90. (I haven't had to write
code to scale data axes for plotting since I linked up an old tektronix
plotter to a VAX terminal back in old day...well, mid-80's)
In this situation, the destination was more important than the journey.
paulv
p.s. The system was a Sun dual 250MHz processor with the optional
Creator 3-D graphics accelerator and 512MB of RAM. I don't know if the
graphics extras helped the IDL OG plotting speed or not, and although
it's not a super flash machine, it was pretty zippy. So, given all that,
I couldn't justify using IDL's OG at all.
Maybe things have changed since IDL v5.0 but the first impression has
stuck like sh*t to a blanket. :o)
--
Paul van Delst Ph: (301) 763-8000 x7274
CIMSS @ NOAA/NCEP Fax: (301) 763-8545
Rm.202, 5200 Auth Rd. Email: pvandelst@ncep.noaa.gov
Camp Springs MD 20746
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