[petsc-users] Coloring of -mat_view draw

[Matthew Knepley]

On Tue, Sep 6, 2016 at 2:50 AM, Justin Chang <jychang48 at gmail.com> wrote:

> Thanks all,
>
> How do you turn off the zero-filling?
>

-dm_preallocate_only

   Matt


> Justin
>
> On Monday, September 5, 2016, Matthew Knepley <knepley at gmail.com> wrote:
>
>> On Mon, Sep 5, 2016 at 4:31 AM, Dave May <dave.mayhem23 at gmail.com> wrote:
>>
>>> On 5 September 2016 at 10:43, Justin Chang <jychang48 at gmail.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>> So i used the following command-line options to view the non-zero
>>>> structure of my assembled matrix:
>>>>
>>>> -mat_view draw -draw_pause -1
>>>>
>>>> And I got an image filled with cyan squares and dots. However, if I
>>>> right-click on the image a couple times, I now get cyan, blue, and red
>>>> squares. What do the different colors mean?
>>>>
>>>
>>> Red represents positive numbers.
>>> Blue represents negative numbers.
>>>
>>> I believe cyan represents allocated non-zero entries which were never
>>> populated with entries (explicit zeroes). Someone will correct me if I am
>>> wrong here regarding cyan...
>>>
>>
>> When DMMatrix() is called, it first preallocates a matrix, then fills it
>> with zeros and assembles. This is the cyan matrix. Then
>> you fillit with nonzeros. This is the second picture with red and blue.
>> There is an option for turning off the zero filling.
>>
>>   Matt
>>
>>
>>> Thanks,
>>>   Dave
>>>
>>>
>>>> Attached are the images of the two cases:
>>>>
>>>> Thanks,
>>>> Justin
>>>>
>>>
>>>
>>
>>
>> --
>> What most experimenters take for granted before they begin their
>> experiments is infinitely more interesting than any results to which their
>> experiments lead.
>> -- Norbert Wiener
>>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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