| Misc. Bugs & Problems [message #14388] |
Wed, 24 February 1999 00:00  |
Steve Scheele
Messages: 6
Registered: February 1999
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Junior Member |
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I am running IDL V5.2 on WinNT and have encountered the following bugs and
problems. All have been discussed with RSI technical support.
;********************
Problem: Sort slows down considerably when sorting integer arrays containing
many identical values.
Workaround: Add small-random values to the array before sorting - improves
sorting by 40X
;********************
Bug: Passing a UINT array to REBIN crashes IDL
Workaround: Don't do that
;********************
Bug: Resizing a draw widget, flips vertical sliders up side down.
Workaround: Pass an initial value to the slider - this workaround is
apparently machine/OS dependent. It didn't work for me.
;********************
Problem: The IDL Code printer font size is proportional to, larger than, but
not the same size as display font. There is no independent control over the
printer font. Making the problem worse is fact that IDL prints line numbers
with the code. I use a 10pt display size which results in an 11.5pt print
size which runs the printed code off the right margin. As a result the IDL
code printer is worthless to me.
Workaround: Use another program to print the code - large pain!
;********************
Problem: In spite of RSI documentation to the contrary, IDL has no true
global variables.
Workaround: User defined system variables - RSI really doesn't like this
workaround
;********************
Bug: RANDOMN has a bug which can cause HISTOGRAM (with a variable BINSIZE)
to fail. When RANDOMN and HISTOGRAM are both in a long For loop, a "corrupt
array descriptor" error message is eventually displayed. This bug is related
to calling RANDOMN with an uninitialized or variable Seed.
Workaround: Pass BINSIZE as a string to HISTOGRAM
;********************
Problem: TrueType display fonts look lousy
Workaround: None
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| Re: Misc. Bugs & Problems [message #14517 is a reply to message #14388] |
Fri, 26 February 1999 00:00  |
steinhh
Messages: 260
Registered: June 1994
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Senior Member |
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Steve Scheele wrote:
> The test case I have been using is;
[...]
> ;following causes the slider to flip 180 deg., putting the min value at
> ;top and the max value at the bottom
> Widget_Control, Draw, Draw_XSize=75
[...]
Doesn't happen on my machine... I always get minimum value at
bottom, on { alpha OSF unix 5.2 Oct 30 1998} with Mwm...
Regards,
Stein Vidar
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| Re: Misc. Bugs & Problems [message #14519 is a reply to message #14388] |
Fri, 26 February 1999 00:00 |
David Kastrup
Messages: 33
Registered: February 1998
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Member |
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"Steve Scheele" <sscheele@scitor.com> writes:
> < Problem: Sort slows down considerably when sorting integer arrays
>> containing many identical values. (on NT)
>
>> Note that this seems to be platform dependent.
>
> Yes - It is also my understanding that Sort uses the sort algorithm
> that is native to the particular OS. I had thought that Sort used
> quick sort. However, quick sort slows down considerably when
> sorting arrays already in (mostly) sorted order. My testing failed
> to show this particular problem.
Only naive quicksort slows down on sorted elements. The usual variant
is the median of three quicksort picking the pivot from a median of
first, last and middle element of a range. The most inefficient
configuration for this sort is pretty hard to come up by design, but
is also O(n^2).
When you are using the GNU C library, qsort really reverts to a
mergesort method unless memory is scarce.
--
David Kastrup Phone: +49-234-700-5570
Email: dak@neuroinformatik.ruhr-uni-bochum.de Fax: +49-234-709-4209
Institut f�r Neuroinformatik, Universit�tsstr. 150, 44780 Bochum, Germany
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| Re: Misc. Bugs & Problems [message #14523 is a reply to message #14388] |
Thu, 25 February 1999 00:00 |
Steve Scheele
Messages: 6
Registered: February 1999
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Junior Member |
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I'll give it a try.
<menakkis@my-dejanews.com> wrote in message
news:7b2mg7$ua$1@nnrp1.dejanews.com...
> "Steve Scheele" <sscheele@scitor.com> wrote:
>> ;********************
>> Bug: Resizing a draw widget, flips vertical sliders up side down.
>>
>> Workaround: Pass an initial value to the slider - this workaround is
>> apparently machine/OS dependent. It didn't work for me.
>
> I think I have a genuine workaround for NT. Using IDL 5.2 / WinNT, with a
> widget that contains a menu, draw widget and vertical slider the full
height
> of the draw widget... I initially create the slider with:
> sl=widget_slider(b0,min=0L,max=10000L,val=10000L,/suppress,u val=2,/vert)
When
> handling the main widget's resize call, I find I have to do:
> widget_control,sl,set_slider_max=0L,set_slider_min=10000L The astute
reader
> will notice that the min and max are now the reverse of what was used in
the
> creation call, and that seems to balance out whatever happened to the poor
> thing during the resize. (Well, on NT at least.) I think it keeps on
> working too (i.e., for any further resizes).
>
> Peter Mason
>
> -----------== Posted via Deja News, The Discussion Network ==----------
> http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
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| Re: Misc. Bugs & Problems [message #14524 is a reply to message #14388] |
Thu, 25 February 1999 00:00 |
Steve Scheele
Messages: 6
Registered: February 1999
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Junior Member |
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< Problem: Sort slows down considerably when sorting integer arrays
> containing many identical values. (on NT)
> Note that this seems to be platform dependent.
Yes - It is also my understanding that Sort uses the sort algorithm that is
native to the particular OS. I had thought that Sort used quick sort.
However, quick sort slows down considerably when sorting arrays already in
(mostly) sorted order. My testing failed to show this particular problem.
< Bug: Resizing a draw widget, flips vertical sliders up side down.
< Workaround: Pass an initial value to the slider
> Could somebody give a tiny example of this - I'm not exactly clear on what
this means.
The test case I have been using is;
;*********************************************************** ******
Pro TestSlider
TLB = Widget_Base(/Row, XPad=10, /Map, XSize=200, YSize=200)
Slider = Widget_Slider(TLB, Maximum=100, Minimum=0, /Vertical)
Draw = Widget_Draw(TLB)
;following causes the slider to flip 180 deg., putting the min value at
top and the max value at the bottom
Widget_Control, Draw, Draw_XSize=75
XManager, 'TLB, TLB
End
RSI's workaround is to build the slider with an explicit value, i.e.
Slider = Widget_Slider(TLB, Maximum=100, Minimum=o, /Vertical,
Value=50)
This didn't work for me. Apparently both the problem and workaround are IDL
version and OS (and OS version) specific. My test code worked proberly using
IDL V5.1 on both NT and SUN/Solaris.
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