get node ids from a sideset and paired nodes in an Action

[KhaledNabilSharafeldin]

Hello,
I have a list of sideset names BoundaryName and looking to get the node ids for all the nodes on these sidesets.

also, if there is a way to get the "PairedBoundaryMapping" for that node easily within action or constraint systems.

Ultimately, I am trying to get a list of primary and secondary node ids.

thanks in advance!

[GiudGiud]

Hello

Use the NodalValueSampler and restrict it to those sidesets with the boundary parameter
https://mooseframework.inl.gov/source/vectorpostprocessors/NodalValueSampler.html
The CSV output will have the list of node ids

Guillaume

[KhaledNabilSharafeldin]

Why do you need to know the global information?

I'm trying to get nodal ids to apply a constraint to these nodes. I still will need to find the node pairs for those, but I haven't looked into that yet. ('getPairedBoundaryMapping' seems to be the method used)

[KhaledNabilSharafeldin]

ok, so i found a way to get the node ids by creating sidesetsfromnormals, then getting the list of nodelist, with the dof_id_type i can get a pointer that holds the position vector and check for the corresponding sides.

but I still have a problem with creating the 8 edge corners as nodesets, since all of this is inaccessible at append_mesh flag , any idea if there's already this functionality implemented? (a nodeset generator for corner nodes)

std::vector<BoundaryName> boundary_names{"xp", "xn","yp", "yn","zp", "zn"};

std::vector<std::vector<dof_id_type>> allLists_from_boundaryNames;
   
for (auto &&name : boundary_names)
    allLists_from_boundaryNames.push_back(_mesh->getNodeList(_mesh->getBoundaryID(name)));

and auto nptr = *_mesh->nodePtr(n); were the functions i needed to build this up, if anyone's interested

[GiudGiud]

You can specify the points manually with this:
https://mooseframework.inl.gov/docs/site/source/meshgenerators/ExtraNodesetGenerator.html

[KhaledNabilSharafeldin]

unfortunately, the _mesh->dimensionWidth(dim) is not accessible at this section as well, i can do it manually, but is there a way to get it otherwise?
so basically I neither have the total dimension of the cube or the corner node ids at that point of the code.

thanks again

[GiudGiud]

So when writing the input file, you will not know where the nodes are?

If so, you can have a look at the source code of this mesh generator and move its functionality to an user object / something that gets executed later on.