Defining Element, Node, and Side Sets for APF Discretizations

Description

In an XML problem definition file the element block, node set and side set parameters specify one-to-one mappings between geometric model entity ids and strings used for material property and boundary condition definitions.

This one-to-one pairing can be replaced with an associations file that supports one-to-many pairings of strings to geometric model entity ids. The format is:

<set type> <name> <N>
<dimension of entity 1> <id of entity 1>
<dimension of entity 2> <id of entity 2>
...
<dimension of entity N> <id of entity N>

Where <set type> is either element block, node set, or side set.

Example

The following example defines a element block with nine geometric model regions that need the same material properties.

<ParameterList name="Discretization">
  ...
  <Parameter name="Element Block Associations" type="TwoDArray(string)" value="2x11:{153, 303, 304, 305, 306, 307, 308, 309, 310, 311, 5, top, ball_1, ball_2, ball_3, ball_4, ball_5, ball_6, ball_7, ball_8, ball_9, bottom}"/>
  <Parameter name="Vertex Node Set Associations" type="TwoDArray(string)" value="2x4:{11, 10, 13, 23, fixedXYZ, fixedX, fixedY, fixedZ}"/>
  ...
</ParameterList>

The definition of these sets in an association file named associations.txt is

element block top 1
3 153 
element block balls 9
3 303
3 304
3 305
3 306
3 307
3 308
3 309
3 310
3 311
element block bottom 1
3 5 
node set fixedXYZ 1
0 11
node set fixedX 1
0 10
node set fixedY 1
0 13
node set fixedZ 1
0 23

And is referenced in the problem definition file with:

<ParameterList name="Discretization">
  ...
  <Parameter name="Model Associations File Name" type="string" value="associations.txt"/>
  ...
</ParameterList>