dolfin team mailing list archive

[Niclas Jansson <njansson@xxxxxxxxxx>]

Patrick Riesen <question92245@xxxxxxxxxxxxxxxxxxxxx> writes:

> Question #92245 on DOLFIN changed:
> https://answers.launchpad.net/dolfin/+question/92245
>
> Patrick Riesen proposed the following answer:
> Murtazo Nazarov wrote:
>> Question #92245 on DOLFIN changed:
>> https://answers.launchpad.net/dolfin/+question/92245
>> 
>> Murtazo Nazarov posted a new comment:
>> 
>> I guess 
>> 
>> *snip*
>>     // extract velocity solution and scale it
>>      dolfin::uint m_e = _e->vector().size();
>>      dolfin::uint m = _v->vector().size();
>>      double* _block = new double[m];
>> 
>>      dolfin::uint* _rows = new dolfin::uint[m];
>>      for(dolfin::uint i = 0; i < m; i++)
>>        _rows[i] = m_e + i;
>> 
>>      _evp->vector().get(_block, m, _rows);
>> *snap*
>> 
>> won't work in parallel or? Otherwise there are many similar ways to deal
>> with the problem.
>> 
>> m
>> 
>
> no, but there's also get_local (), set_local () which are the parallel 
> equivalents.
>

Working with indices, and get_local is dangerous. For example if the
velocity components should be scaled differently it won't work if the
dofmap is renumbered. The safest way is to extract function components
from a given dofmap. 

Niclas