getc3(i, m3, chunk) getc3(i, m3, clist , l, u, fsl, fsu, cells)
Returns cell values of the I th function attached to 3D mesh M3 for cells in the specified CHUNK.
The CHUNK may be a list of cell indices, in which case getc3 returns a (CHUNK. shape) array of
vertex coordinates. CHUNK may also be a mesh-specific data structure used in the slice3 routine
(see ``slice3: Plane and Isosurface Slices of a 3D mesh'' on page ![[*]](crossref.png)
), in which case getc3 may return
a (ni) x(nj) x(nk) array of vertex values. There is no savings in the amount of data for such a
CHUNK, but the gather operation is cheaper than a general list of cell indices. Use getc3 when writing
coloring functions for slice3.
If CHUNK is a CLIST, the additional arguments L, U, FSL, and FSU are vertex index lists which override the CLIST if the I th attached function is defined on mesh vertices. L and U are index arrays into the (CLIST. shape) x2x2x2 vertex value array, say vva, and FSL and FSU are corresponding interpolation coefficients; the zone centered value is computed as a weighted average of involving these coefficients. The CELLS argument is required by histogram to do the averaging. See the source code for details. By default, this conversion (if necessary) is done by averaging the eight vertex-centered values.
getc3_rect does the job for a regular rectangular mesh.
getc3_irreg: Same thing as getc3_rect, i. e., returns the same type of data structure, but
from an irregular mesh. m3[1] is a 2-list; m3[1][0] is an array whose i th element is an array of
coordinate indices for the i th cell, or a list of up to four such arrays. m3 [1] [1] is the 3 by nverts
array of coordinates. m3 [2] is a list of arrays of vertex-centered or cell-centered data. chunk may
be a list, in which case chunk [0] is a 2-sequence representing a range of cell indices; or it may be
a one-dimensional array, in which case it is a nonconsecutive set of cell indices. It is guaranteed that
all cells indexed by the chunk are the same type.