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Re: Quit versus Clear["Global`*"]

  • To: mathgroup at smc.vnet.net
  • Subject: [mg121304] Re: Quit versus Clear["Global`*"]
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Thu, 8 Sep 2011 05:27:04 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201109042206.SAA21533@smc.vnet.net> <j42b3a$rrv$1@smc.vnet.net>
  • Reply-to: drmajorbob at yahoo.com

I don't think anything is happening in parallel; it takes TWO or more  
kernels for that.

Bobby

On Wed, 07 Sep 2011 07:29:35 -0500, Kevin J. McCann  
<Kevin.McCann at umbc.edu> wrote:

> But then shouldn't the kernel restart on the next line? If not, then
> when would the kernel restart? Never? After we wait a few seconds?
>
> Quit (* the kernel quits *)
> x=1; (* shouldn't the kernel restart here? *)
>
> Actually, it appears that Quit takes some time to execute, and in
> parallel, further commands execute, but then their results are killed  
> off.
>
> Kevin
>
> On 9/7/2011 5:41 AM, DrMajorBob wrote:
>> No, the point is that when Quit is the first command, the kernel  
>> quits...
>> rather than continuing to evaluate initialization cells. That appears
>> entirely sequential, to me.
>>
>> Bobby
>>
>> On Tue, 06 Sep 2011 05:13:30 -0500, Kevin J. McCann<kjm at kevinmccann.com>
>> wrote:
>>
>>> I guess the point here is that when commands are listed sequentially,  
>>> at
>>> least with Quit at the top, they are not carried out that way, but
>>> perhaps in some parallel fashion. This is not documented anywhere, and  
>>> I
>>> don't think it is expected behavior. Further, I think it is not
>>> desirable.
>>>
>>> Kevin
>>>
>>> On 9/5/2011 4:23 PM, DrMajorBob wrote:
>>>> OK, putting it in a separate cell didn't help, but if you Quit while
>>>> evaluating initialization cells... you'll stop evaluating them. (Not  
>>>> so
>>>> surprising, really.)
>>>>
>>>> So instead of Quit, add Clear and ClearAll for everything that needs
>>>> it. In the code of your example, there's nothing that needs it.
>>>>
>>>> Whenever I define a function that could EVER need Clear, I precede  
>>>> that
>>>> definition with Clear. To start all over, I can go to the menus and
>>>> select Evaluate>Evaluate Initialization Cells. When in doubt, I quit
>>>> the kernel with Evaluation>Quit Kernel, particularly if evaluating  
>>>> code
>>>> is in an infinite (or very long?) loop.
>>>>
>>>> spell and spell1 are Off by default at my machine, by the way. I'm not
>>>> sure what that would be so here, but not at your machine. I used to
>>>> have to turn them off manually, but that was a long time ago.
>>>>
>>>> Bobby
>>>>
>>>> On Mon, 05 Sep 2011 15:00:46 -0500, Kevin J. McCann
>>>> <kjm at kevinmccann.com>  wrote:
>>>>
>>>>> I have to wait for Quit to finish executing, and then execute the  
>>>>> rest.
>>>>>
>>>>> On 9/5/2011 1:40 PM, DrMajorBob wrote:
>>>>>> Put Quit in a cell by itself.
>>>>>>
>>>>>> Bobby
>>>>>>
>>>>>> On Mon, 05 Sep 2011 07:15:08 -0500, Kevin J. McCann
>>>>>> <kjm at kevinmccann.com>  wrote:
>>>>>>
>>>>>>> This is a related observation to the use of Quit.
>>>>>>>
>>>>>>> I have an initialization cell at the top of most of my notebooks
>>>>>>> that loads my favorite packages and sets options. If I put Quit at
>>>>>>> the top of all that, and then execute the whole section, the Quit
>>>>>>> seems to override everything, i.e. at the end nothing is defined.
>>>>>>>
>>>>>>> It appears that while Quit is executing, the other commands do, but
>>>>>>> then the Quit kills off the results. I am not explaining it well,  
>>>>>>> so
>>>>>>> here is some abbreviated code from one of my nb's. Dump it all into
>>>>>>> an Input cell and execute. At the end you will see that x is not
>>>>>>> defined.
>>>>>>>
>>>>>>> Kevin
>>>>>>>
>>>>>>> Quit
>>>>>>> Off[General::spell];
>>>>>>> Off[General::spell1];
>>>>>>> bs = {FontFamily ->  "Arial", FontSize ->  14, FontWeight ->   
>>>>>>> Bold};
>>>>>>> SetOptions[Plot,
>>>>>>>         Frame ->  True,
>>>>>>>         FrameStyle ->  AbsoluteThickness[2],
>>>>>>>         GridLines ->  Automatic,
>>>>>>>         PlotStyle ->  {{Red, AbsoluteThickness[3]}, {Black,
>>>>>>>        AbsoluteThickness[3]}, {Blue,
>>>>>>>        AbsoluteThickness[3]}, {Darker@Green,  
>>>>>>> AbsoluteThickness[3]}},
>>>>>>>     BaseStyle ->  bs
>>>>>>>     ];
>>>>>>> SetOptions[ListPlot,
>>>>>>>         Frame ->  True,
>>>>>>>         FrameStyle ->  AbsoluteThickness[2],
>>>>>>>         GridLines ->  Automatic,
>>>>>>>         PlotStyle ->  {Blue, AbsolutePointSize[2]},
>>>>>>>     BaseStyle ->  bs
>>>>>>>     ];
>>>>>>> $Post := (If[MatrixQ[#], MatrixForm[#], #]&)
>>>>>>> x = 22/7.;
>>>>>>>
>>>>>>> On 9/5/2011 7:16 AM, DrMajorBob wrote:
>>>>>>>> No. For that, you need:
>>>>>>>>
>>>>>>>> Quit
>>>>>>>>
>>>>>>>> Bobby
>>>>>>>>
>>>>>>>> On Sun, 04 Sep 2011 17:06:32 -0500, Themis
>>>>>>>> Matsoukas<tmatsoukas at me.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> So, if I use ClearAll["Global`*"] at the beginning of a notebook
>>>>>>>>> and
>>>>>>>>> execute all the cells, is it the same as running on a fresh  
>>>>>>>>> kernel?
>>>>>>>>>
>>>>>>>>> Themis
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>>>
>>>>
>>>>
>>
>>
>


-- 
DrMajorBob at yahoo.com




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