Building an EBIndexSpace

We provide some elementary facilities for building an EBIndexSpace , based on providing support for the following two-pass algorithm. In the first pass, one builds the node structure, adding one node at a time. At the same time, one can build auxiliary data structures describing the geometry of the irregular nodes, using the fact that they are being stored in a vector. In the second pass, one uses the information constructed in the first pass to build up the edge structure, again adding one edge at a time. In addition to this facility, we also provide the capability of generating the union of two EBIndexSpace s, i.e. the EBIndexSpace for the union of the two bodies, under the assumption that the bodies are sufficiently well-separated. Finally, we can turn a shape inside-out, reversing the roles of the covered and exposed regions. While these three capabilities are by no means exhaustive, it is possible using these methods to generate grids for a variety of complex shapes.

The member functions for EBIndexSpace that are used in this process are given as follows.

• Constructors. We have a default constructor, as well as a define function. isp.define(Box base,int depth) set up overall domain geometry: the grid containing the EBIndexSpace is the Box base refined by a factor of in each direction.
• Node isp.addIrregNode(IntVect iv) adds an irregular Node at location iv, returning the value of the irregular Node.

  isp.makeRegular(IntVect iv), isp.makeCovered(IntVect iv) makes the cells at iv regular or covered, respectively.

  void isp.addEdge(Node nLow, Node nHigh) adds the Edge with low and high Node s nLow,nHigh.

• isp.close() closes the EBIndexSpace isp from further modification, and runs consistency checks, e.g., no covered cell should abut a regular cell. If that occurs, it tries to make the EBIndexSpace consistent by converting regular Node s to irregular Node s, or exits with an error if it does not succeed.