cherab.imas.math.tetrahedralize.cell_to_5tetra¶

cherab.imas.math.tetrahedralize.cell_to_5tetra(cells)¶

Generate tetrahedral indices by dividing one cell into 5 tetrahedra.

One cubic-like cell having 8 vertices can be divided into a minimum of five tetrahedra. Reference: https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/48509/versions/3/previews/COMP_GEOM_TLBX/html/Divide_hypercube_5_simplices_3D.html # noqa: E501

Note

If one side face of the cell is twisted, Adjacent cells do not share a plane with each other. In this case, it is required to alternate combinations of tetrahedra, or simply use cell_to_6tetra().

Parameters:

cells : (N,8) ndarray [numpy.int32]¶

cell indices 2D array, the shape of which is \((N, 8)\), where \(N\) is the number of cells.

Returns:

tetrahedra indices array, the shape of which is \((5N, 4)\).

Return type:

(5N,4) ndarray

Examples

>>> import numpy as np
>>> from cherab.imas.math.tetrahedralize import cell_to_5tetra
>>>
>>> array = np.arrange(16, dtype=np.int32).reshape((2, -1))
>>> array
array([[ 0,  1,  2,  3,  4,  5,  6,  7],
       [ 8,  9, 10, 11, 12, 13, 14, 15]], dtype=int32)
>>> cell_to_5tetra(array)
    array([[ 0,  1,  3,  4],
           [ 1,  3,  4,  6],
           [ 3,  6,  7,  4],
           [ 1,  2,  3,  6],
           [ 1,  6,  4,  5],
           [ 8,  9, 11, 12],
           [ 9, 11, 12, 14],
           [11, 14, 15, 12],
           [ 9, 10, 11, 14],
           [ 9, 14, 12, 13]], dtype=int32)