Module shape 

Shape functions and reference derivatives of the 3-node triangle (natural coordinates xi, eta on the unit triangle) and the 4-node quadrilateral (xi, eta in [-1, 1]). Node order is counter-clockwise; quad node k sits at the reference corner QUAD4_CORNERS[k].

Constants

QUAD4_CORNERS

Reference corners of the bilinear quadrilateral, in node order.

Functions

quad4_dshape

[dN_i/dxi, dN_i/deta] for the quadrilateral.

quad4_shape

N_i(xi, eta) = (1 + xi_i xi)(1 + eta_i eta) / 4.

tri3_dshape

[dN_i/dxi, dN_i/deta] for the triangle (constant).

tri3_shape

N_i(xi, eta) for the triangle: 1 - xi - eta, xi, eta.