B.3.4 Nodes

Index:	10
Scheme symbol:	xf-node
C macro:	XF_NODE
Status:	required

Format:

      (10 (zone-id first-index last-index type ND)(
      x1 y1 z1
      x2 y2 z2
      .
      .
      .
      ))

• If zone-id is zero, this provides the total number of nodes in the grid. first-index will then be one, last-index will be the total number of nodes in hexadecimal, type is equal to 1, ND is the dimensionality of the grid, and there are no coordinates following (the parentheses for the coordinates are omitted as well).

  For example: (10 (0 1 2d5 1 2))

• If zone-id is greater than zero, it indicates the zone to which the nodes belong. first-index and last-index are the indices of the nodes in the zone, in hexadecimal. The values of last-index in each zone must be less than or equal to the value in the declaration section. Type is always equal to 1.

  ND is an optional argument that indicates the dimensionality of the node data, where ND is 2 or 3.

  If the number of dimensions in the grid is two, as specified by the node header, then only $x$ and $y$ coordinates are present on each line.

The following is an example of a 2D grid:

      (10 (1 1 2d5 1 2)(
      1.500000e-01 2.500000e-02
      1.625000e-01 1.250000e-02
                .
                .
                .
      1.750000e-01 0.000000e+00
      2.000000e-01 2.500000e-02
      1.875000e-01 1.250000e-02
      ))

Because the grid connectivity is composed of integers representing pointers (see Cells and Faces), using hexadecimal conserves space in the file and provides for faster file input and output. The header indices are in hexadecimal so that they match the indices in the bodies of the grid connectivity sections. The zone-id and type are also in hexadecimal for consistency.