matrix building question

[Barry Smith]

On Dec 15, 2009, at 5:55 PM, Matt Funk wrote:

> Sorry,
>
> i should have been more specific. Of course there cannot be 'holes':
> What i meant was this:
>
> could i, in theory, build a matrix that with the following layout:
> rows: 0-249 owned by proc0
> rows: 250-499 owned by proc1
> rows: 500-749 owned by proc0
> rows: 750-999 owned by proc1
>
No, you cannot do this.

    Barry

> or does it have be like such:
> rows: 0-499 owned by proc0
> rows: 500-999 owned by proc1
>
>
> matt
>
> On Tuesday 15 December 2009, Barry Smith wrote:
>>   No, there cannot be holes in the rows of matrix.
>>
>>    Barry
>>
>> On Dec 15, 2009, at 4:58 PM, Matt Funk wrote:
>>> Hi,
>>>
>>> i was wondering if it is mandetory that when i populate a parallel
>>> matrix,
>>> that all rows owned by given processor are continously numbered?
>>>
>>> I.e. say that a given process owns 500 rows. Could i build the
>>> matrix such
>>> that the first 250 rows have row numbers: 0-250 and the second 250
>>> rows have
>>> row numbers, say: 750-1000?
>>>
>>> Or do they HAVE to be numbered continous, for example: 0-500 or
>>> 250-750?
>>>
>>> I was under the impression that they had to be continously numbered
>>> due to the
>>> example given on p.55 of the user manual. However, i might have  
>>> simply
>>> misunderstood what it is saying.
>>> Also, reading the section on paritioning makes me think that it
>>> might be
>>> possible to break the numbering up as mentioned above.
>>>
>>> I hope i am making sense ...
>>>
>>>
>>> thanks
>>> matt
>>
>