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Re: Kernel crash, version 7.0, windows XP, when using slider in Manipulate

• To: mathgroup at smc.vnet.net
• Subject: [mg109401] Re: Kernel crash, version 7.0, windows XP, when using slider in Manipulate
• From: Albert Retey <awnl at gmx-topmail.de>
• Date: Sun, 25 Apr 2010 06:24:56 -0400 (EDT)
• References: <hqu8dj$rqc$1@smc.vnet.net>

Am 24.04.2010 09:59, schrieb Nasser M. Abbasi:
> Hi;
> 
> I was wondering if someone has a real Mathematica debugger that they could 
> use to help me find where this bug is? I do standard mathematica.
> 
> I spend the last 6 hrs on this, and can't find the problem. I do not have a 
> debugger, so it is impossible to find where the bug is since it is a kernel 
> crash and I do not see what I am doing wrong.  One thing I know is that if I 
> all the Epilog code in the code, the problem goes away.
> 
> This is the problem:
> 
> I have a manipulate, with a plot being drawn using Dynamics in the control 
> area. The plots uses control variables.
> 
> When I enter a value of a control variable using the slider (i.e. normal 
> method) there is no problem. no crash, even though the slider goes over the 
> same input value which will cause a crash when I enter this input as 
> follows:
> 
> I open the slider by clicking open on the small "+" next to the slider, and 
> type in a numerical value, the kernel crashes.
> 
> For example, There is a control variable called zeta in the program. When I 
> move the slider  no crash happens. When I open the slider window and type in 
> a value then the crash happens. The strange thing, if I type in   "1" 
> instead of "1.0" then it will crash, but if I type "1." no crash is seen 
> (i.e. add a decimal point !)
> 
> I have a screen shot here to help you see the problem:
> 
> http://12000.org/tmp/bug_input_slider/screen_shot.png
> 
> And the notebook is in the same folder, here:
> 
> http://12000.org/tmp/bug_input_slider/
> 
> it is called filter_v9.nb
> 
> All what you have to do just download the notebook, open it in Mathematica, 
> open the slider input area just like shown in the above image, and type in 1
> Next, simply hit any other control with the mouse to activate, now the 
> kernel will crash.
> 
> As I said, if I type 1. instead of 1 (i.e. with a decimal point), the 
> problem does not happen.
> 
> Any one has version 7.0.1? does the problem happens with it also?

I have not tried any of your code and I could be completley wrong, but
what you describe looks a lot like your code makes mathematica crash for
input which are not machine precision numbers (1 is very different to 1.
in this respect). When you use the slider, I think it will always return
machine precision numbers so it could explain the difference. Have you
tried to run the code within the Dynamic with setting zeta=1 without the
Dynamic? Is that turns out to be the problem a N[] at the right place
will probably make your problem go away...

Here is a little example which shows my point:

Manipulate[{x, Head[x]}, {x, 0, 1}]


hth,

albert