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

  • To: mathgroup at smc.vnet.net
  • Subject: [mg121295] Re: Quit versus Clear["Global`*"]
  • From: "Kevin J. McCann" <Kevin.McCann at umbc.edu>
  • Date: Wed, 7 Sep 2011 08:29:35 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201109042206.SAA21533@smc.vnet.net> <j42b3a$rrv$1@smc.vnet.net> <j47e8e$l24$1@smc.vnet.net>

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
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>
>>>
>
>




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