Re: [Libmesh-users] question about the numeric vector

[Roy S. <roy...@ic...>]

On Thu, 25 Jan 2018, Michael Povolotskyi wrote:

> I will add another system and will not solve it.

Make sure it's ExplicitSystem (no, wait, maybe just plain System?
ExplicitSystem does still allocate an rhs, not just a solution).

ImplicitSystem will try to allocate a Jacobian for you whether you
plan to eventually assemble and solve with it or not, and that can get
expensive.
---
Roy


> On 01/25/2018 08:25 AM, Roy Stogner wrote:
>>
>>  On Wed, 24 Jan 2018, Paul T. Bauman wrote:
>>
>>>  Sorry for slow response. I have nothing better to offer other than 3
>>>  vectors, but maybe others will.
>>
>>  You can add another ExplicitSystem to the mesh, giving it a
>>  vector-valued variable corresponding to your solution system's
>>  scalar-valued variable.
>>
>>  This is more flexible (if you have multiple variables in your solution
>>  system but only want to add a vector-valued postprocessed field for
>>  one of them, for instance) but probably a bit harder to work with.
>>  ---
>>  Roy
>>
>>>  On Mon, Jan 22, 2018 at 12:40 PM, Michael Povolotskyi
>>>  <mpo...@pu...>
>>>  wrote:
>>>
>>>>  Dear Libmesh developers and users,
>>>>
>>>>  I need to compute a field on mesh based on a solution.
>>>>
>>>>  To do so I usually add a vector to a system and fill it with data.
>>>>
>>>>  This works perfectly for a scalar field.
>>>>
>>>>  What would you recommend to do for a vector field.
>>>>
>>>>  Of course, I can add 3 vectors, one for each component of the field. Is
>>>>  there a better way?
>>>>
>>>>  Thank you,
>>>>
>>>>  Michael.
>>>> 
>>>>
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