On 03/05/2018 02:54 PM, Feimi Yu wrote:
I changed my strategy to use set(r, c, v) function to set the values so that I
can use the const iterators. also called compress after every add:
for(autor =Abs_A_matrix->block(0, 0).local_range().first;
r <Abs_A_matrix->block(0, 0).local_range().second; ++r)
{
for(autoitr =Abs_A_matrix->block(0, 0).begin(r);
itr !=Abs_A_matrix->block(0, 0).end(r);
++itr)
{
Abs_A_matrix->block(0, 0).set(itr->row(), itr->column(),
std::abs(itr->value()));
Abs_A_matrix->block(0, 0).compress(VectorOperation::add);
}
}
This time it says:
*** Error in ' ' :free(): invalid size: 0x0000556443d63e50 ***
This seems like a out of bounds access. This happens even when I run with 1
process.
This is the right approach -- you do need to restrict work to the locally
owned range of rows, but if you do that on every processor, then you cover all
rows.
But you can't call 'compress()' after every set operation. That's because
compress() is a *collective* operation, i.e., it has to be called on all
processors at the same time. Since different processors may have different
numbers of entries, what you are doing here leads to different numbers of
calls on different processors.
In addition, it is *very* inefficient to call the function so many times. Just
move the call to after the loop. (And change the argument to
VectorOperation::set -- you are *setting* elements, after all, not adding to
them.)
Best
W.
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Wolfgang Bangerth email: [email protected]
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