Tangent vector calculation for 2+ noded elements.

Calculates the tangent vector interpolating every dimension separately. It uses a (n_nodes - 1) degree polynomial, and the differentiation is analytical.

Calculation method:

  1. A n_nodes-1 polynomial is fitted through the nodes per dimension.

  2. Those polynomials are analytically differentiated with respect to the node index

  3. The tangent vector is given by:

\[\vec{t} = \frac{s_x'\vec{i} + s_y'\vec{j} + s_z'\vec{k}}{\left| s_x'\vec{i} + s_y'\vec{j} + s_z'\vec{k}\right|}\]

where \('\) notes the differentiation with respect to the index number

param in_coord:

array of coordinates of the nodes. Dimensions = [n_nodes, ndim]

type in_coord:



Dimensions are treated independent from each other, interpolating polynomials are computed individually.