On Fri, Dec 9, 2011 at 11:02 PM, Satish Balay wrote:
> On Fri, 9 Dec 2011, Xiangdong Liang wrote:
>
>> Another quick question, when I use mat_view_draw command line option,
>> how can I make the figure X window larger? I think petsc
>> PetscDrawOpenX can do this job, but just wondering whether any
On Fri, 9 Dec 2011, Xiangdong Liang wrote:
> Another quick question, when I use mat_view_draw command line option,
> how can I make the figure X window larger? I think petsc
> PetscDrawOpenX can do this job, but just wondering whether any quick
> command line options? Thanks.
You can use '-mat_vi
On Fri, Dec 9, 2011 at 7:23 PM, Matthew Knepley wrote:
> On Fri, Dec 9, 2011 at 6:15 PM, Xiangdong Liang wrote:
>>
>> If I use MAT_IGNORE_ZERO_ENTRIES option, is it possible that I still
>> see some zeros in the sparse matrix? In my problem, when I use this
>
>
> Not if they are truly zero.
>
>>
If I use MAT_IGNORE_ZERO_ENTRIES option, is it possible that I still
see some zeros in the sparse matrix? In my problem, when I use this
ignore_zero options, the number of nonzeros is significantly reduced
(from mat_view_info) but still larger than the number of nonzeros
counting from matlab. When
On Fri, Dec 9, 2011 at 6:15 PM, Xiangdong Liang wrote:
> If I use MAT_IGNORE_ZERO_ENTRIES option, is it possible that I still
> see some zeros in the sparse matrix? In my problem, when I use this
>
Not if they are truly zero.
> ignore_zero options, the number of nonzeros is significantly reduc
On Wed, Dec 7, 2011 at 12:07 PM, Satish Balay wrote:
> On Wed, 7 Dec 2011, Xiangdong Liang wrote:
>
>> >> >> Matrix Object:
>> >> >> type=mpiaij, rows=10, cols=10
>> >> >> total: nonzeros=20, allocated nonzeros=40
>> >> >> ? not using I-node (on process 0) routines
>> >> >>
>> >> >> Is there a way
On Wed, Dec 7, 2011 at 4:44 AM, Matthew Knepley wrote:
> On Tue, Dec 6, 2011 at 11:39 PM, Xiangdong Liang wrote:
>>
>> On Wed, Dec 7, 2011 at 12:11 AM, Barry Smith wrote:
>> >
>> > On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
>> >
>> >> Hello everyone,
>> >>
>> >> Can anyone help on the u
On Wed, Dec 7, 2011 at 11:53 AM, Satish Balay wrote:
> On Wed, 7 Dec 2011, Xiangdong Liang wrote:
>
>> I think I did have 10 zeros entries. In my script, I have inserted
>> zeros by MatSetValue(A,i, (i+1)%N, 0.0, ADD_VALUES); Why doesn't that
>> option matter in my case? That option prevents PETSc
On Wed, Dec 7, 2011 at 9:28 AM, Barry Smith wrote:
>
> On Dec 6, 2011, at 11:39 PM, Xiangdong Liang wrote:
>
>> On Wed, Dec 7, 2011 at 12:11 AM, Barry Smith wrote:
>>>
>>> On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
>>>
Hello everyone,
Can anyone help on the usage of MAT_IG
On Wed, 7 Dec 2011, Satish Balay wrote:
> As indicated call "MatSetOption(A,MAT_IGNORE_ZERO_ENTRIES,PETSC_TRUE)
> - before any calls to MatSetValue/s()
>
> And verify with MatView()
Ok - here is what you can see with a slightly modified mat/examples/tests/ex38.c
Notice "C[0,1] = 0.0" and thats
On Wed, 7 Dec 2011, Xiangdong Liang wrote:
> >> >> Matrix Object:
> >> >> type=mpiaij, rows=10, cols=10
> >> >> total: nonzeros=20, allocated nonzeros=40
> >> >> ? not using I-node (on process 0) routines
> >> >>
> >> >> Is there a way to have nonzeros=10, and allocated nonzeros=10, since
> >> >>
On Wed, 7 Dec 2011, Xiangdong Liang wrote:
> I think I did have 10 zeros entries. In my script, I have inserted
> zeros by MatSetValue(A,i, (i+1)%N, 0.0, ADD_VALUES); Why doesn't that
> option matter in my case? That option prevents PETSc from inserting
> zeros, doesn't it? Thank you.
MatSetValue
On Dec 6, 2011, at 11:39 PM, Xiangdong Liang wrote:
> On Wed, Dec 7, 2011 at 12:11 AM, Barry Smith wrote:
>>
>> On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
>>
>>> Hello everyone,
>>>
>>> Can anyone help on the usage of MAT_IGNORE_ZERO_ENTRIES? Suppose I
>>> want to have a 10-by-10 spa
On Tue, Dec 6, 2011 at 11:39 PM, Xiangdong Liang wrote:
> On Wed, Dec 7, 2011 at 12:11 AM, Barry Smith wrote:
> >
> > On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
> >
> >> Hello everyone,
> >>
> >> Can anyone help on the usage of MAT_IGNORE_ZERO_ENTRIES? Suppose I
> >> want to have a 10-b
On Wed, Dec 7, 2011 at 12:11 AM, Barry Smith wrote:
>
> On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
>
>> Hello everyone,
>>
>> Can anyone help on the usage of MAT_IGNORE_ZERO_ENTRIES? Suppose I
>> want to have a 10-by-10 sparse matrix, where each row has maximum two
>> nonzeros. I would li
Hello everyone,
Can anyone help on the usage of MAT_IGNORE_ZERO_ENTRIES? Suppose I
want to have a 10-by-10 sparse matrix, where each row has maximum two
nonzeros. I would like to have petsc ignore the 0.0 values by not
allocating space for 0.0 values. In my problem, the nonzero pattern of
sparse
On Dec 6, 2011, at 10:26 PM, Xiangdong Liang wrote:
> Hello everyone,
>
> Can anyone help on the usage of MAT_IGNORE_ZERO_ENTRIES? Suppose I
> want to have a 10-by-10 sparse matrix, where each row has maximum two
> nonzeros. I would like to have petsc ignore the 0.0 values by not
> allocating s
Thanks. If this is the case, will the option MAT_IGNORE_ZERO_ENTRIES be helpful?
Xiangdong
On Thu, Dec 1, 2011 at 8:00 PM, Barry Smith wrote:
>
> On Dec 1, 2011, at 6:44 PM, Xiangdong Liang wrote:
>
>> Hello everyone,
>>
>> I have a question about whether zeros will change the sparse pattern.
>>
The checks in the code are lines like
if (value == 0.0 && ignorezeroentries && (is == ADD_VALUES)) continue;
hence changing the source code to ignore small values is not difficult. But I
think this is a terribly cheesy hack and would hope people would not do this.
Barry
On De
On Dec 1, 2011, at 8:46 PM, Xiangdong Liang wrote:
> Thanks. If this is the case, will the option MAT_IGNORE_ZERO_ENTRIES be
> helpful?
What do you mean by "be helpful"? Sometimes you do want those "zero"
locations represented and sometimes you don't, so sometimes you would use the
option
Hello everyone,
I have a question about whether zeros will change the sparse pattern.
Suppose I am generating two sparse matrices A and B. A is generated
with exactly number of nonzeros, say 10 nnz per row. When I generate
matrix B, I specify 12 nonzeros, but two of them are given zero values
by M
On Dec 1, 2011, at 6:44 PM, Xiangdong Liang wrote:
> Hello everyone,
>
> I have a question about whether zeros will change the sparse pattern.
> Suppose I am generating two sparse matrices A and B. A is generated
> with exactly number of nonzeros, say 10 nnz per row. When I generate
> matrix B,
I was always wondering how difficult it would be to define a constant say,
ZERO_DROP_TOLERANCE so that when the matrix is setup,
MatAssemblyBegin()/End(), it automatically ignores the values below this
threshold?
I understand the for the matrices that might change in successive
iterations, that mig
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