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Index Select operator


Figure 32

The Index select operator selects a subset of a 2D or 3D structured mesh based on ranges of cell indices. Structured meshes have an implied connectivity that allows each cell in the mesh to be specified by an i,j or i,j,k index depending on the dimension of the mesh. The Index select operator allows you to specify different ranges for each mesh dimension. The ranges are used to select a brick of cells from the mesh. In addition to indices, the Index select operator uses stride to select cells from the mesh. Stride is a value that allows the operator to count by 2's, 3's, etc. when iterating through the range indices. Stride is set to 1 by default. When higher values are used, the resulting mesh is more coarse since it contains fewer cells in each dimension. The Index select operator attempts to preserve the size of the mesh when non-unity stride values are used. An example of the Index select operator appears in figure.