expvertices [ <filename> ]

Export the real world coordinates of all vertices to a file. If no filename is given, the list of all vertices and their coordinates is printed in the text window of $\mbox{AGM}^{\mbox{\footnotesize 3D}}$. Else the file is created or overwritten and simultaneously the information is printed in the text window (in a more user friendly format, not the format of the output file). In each line of the file there are the x, y and z-coordinates of a vertex with a precision of 4 digits following the decimal point.

Since the program mesh33 assumes that the line number corresponds with the identifier of the vertex, the lines have to be in the correct order. However, the vertices are stored in a double linked list in the order of their creation. A new vertex is inserted at the beginning and its identifier is derived from the last id which was assigned to a vertex. This number is stored in the variable VertexCounter in the data structure of the multigrid. It does not indicate the total number of vertices but is a simple counter, which is updated whenever a new vertex is created. This happens for example if the grid is refined. Though, the counter is not decreased if the grid is coarsened and a vertex is removed. As long as the grid is not coarsened the vertices are numbered consecutively. It is assumed that this the case. Then the output starts with the last vertex in the list. It was created first and therefore has id 0. The previous vertex is reached by the PRED macro. For security reasons an assert command checks if the output is in the correct order and numbered consecutively.

  

Figure 3: Unit Cube

Furthermore mesh33 expects the centre of the coordinate system to lie inside the domain. By definition vertex no. 0 has the coordinates (0, 0, 0). Consequently all vertices are moved by $(-\frac{1}{2},-\frac{1}{2},-\frac{1}{2})$ before being saved to file. However, the unchanged coordinates are indicated in the text window.