element

The element module defines reference elements such as the LineReference and TriangleReference, but also more exotic objects like the MosaicReference. A set of (interconnected) elements together form a nutils.topology.Topology. Elements have edges and children (for refinement), which are in turn elements and map onto self by an affine transformation. They also have a well defined reference coordinate system, and provide pointsets for purposes of integration and sampling.

class nutils.element.Reference(ndims)

Bases: Singleton

Reference element.

vertices: Array of shape nverts x ndims that defines the coordinates of the element’s vertices.

edge_vertices: Sequence of integer arrays that specifies per edge (outer sequence, corresponding to edges) for each vertex (inner sequence, corresponding to edges[iedge].vertices) its index in vertices.

property simplices

Partition of the element consisting of simplices.

The simplices attribute is a sequence of integer arrays that specify per simplex the indices of the vertices in vertices.

property simplex_transforms

Sequence of transforms from simplex to parent element.

The simplex_transforms attribute is a sequence of objects of type nutils.transform.TransformItem that provide per simplex the coordinate mapping from the simplex to the parent element. The origin of the simplex-local coordinate system maps to its first vertex, the first unit vector to the second, the second to the third, and so on.