ParsedSubdomainMeshGenerator

Example

The desired example mesh is a 1-by-1 2D square which contains Block 1 (a centered 0.8-by-0.8 square) and Block 2 (a 0.4-by-0.4 square located in the bottom left quarter of Block 1). The remaining edge of the square can be Block 0.

The combinatorial expression that defines Block 1 is below.

x > 0.1 & x < 0.9 & y > 0.1 & y < 0.9

The expression

x < 0.5 & y < 0.5

can partially define Block 2, but the region outside Block 1 also needs to be excluded. The input file syntax needed to generate this example is shown below.

[Mesh<<<{"href": "../../syntax/Mesh/index.html"}>>>]
  [gmg]
    type = GeneratedMeshGenerator<<<{"description": "Create a line, square, or cube mesh with uniformly spaced or biased elements.", "href": "GeneratedMeshGenerator.html"}>>>
    dim<<<{"description": "The dimension of the mesh to be generated"}>>> = 2
    nx<<<{"description": "Number of elements in the X direction"}>>> = 10
    ny<<<{"description": "Number of elements in the Y direction"}>>> = 10
    xmax<<<{"description": "Upper X Coordinate of the generated mesh"}>>> = 1
    ymax<<<{"description": "Upper Y Coordinate of the generated mesh"}>>> = 1
  []

  [subdomains]
    type = ParsedSubdomainMeshGenerator<<<{"description": "Uses a parsed expression (`combinatorial_geometry`) to determine if an element (via its centroid) is inside the region defined by the expression and assigns a new block ID.", "href": "ParsedSubdomainMeshGenerator.html"}>>>
    input<<<{"description": "The mesh we want to modify"}>>> = gmg
    combinatorial_geometry<<<{"description": "Function expression encoding a combinatorial geometry"}>>> = 'x > 0.1 & x < 0.9 & y > 0.1 & y < 0.9'
    block_id<<<{"description": "Subdomain id to set for inside of the combinatorial"}>>> = 1
  []

  [subdomains2]
    type = ParsedSubdomainMeshGenerator<<<{"description": "Uses a parsed expression (`combinatorial_geometry`) to determine if an element (via its centroid) is inside the region defined by the expression and assigns a new block ID.", "href": "ParsedSubdomainMeshGenerator.html"}>>>
    combinatorial_geometry<<<{"description": "Function expression encoding a combinatorial geometry"}>>> = 'x < 0.5 & y < 0.5'
    excluded_subdomains<<<{"description": "A set of subdomain names that will not changed even if they are inside/outside the combinatorial geometry"}>>> = '0'
    block_id<<<{"description": "Subdomain id to set for inside of the combinatorial"}>>> = 2
    input<<<{"description": "The mesh we want to modify"}>>> = subdomains
  []
[]

The final mesh output is:

Input Parameters