The Elpric node (
) is a special element for computing the eigenvectors and eigenvalues of square 3-by-3 symmetric matrices. The declaration is similar to the
Variable Declaration node, and this node also generates three new vector variables plus three scalar eigenvalues. You enter the expression of the input matrix in the
Expression field under the
Input Matrix Definition section. The Elpric element also works with unsymmetric matrices, in which case it takes the upper-triangular part of the matrix and mirrors it to the lower-triangular part to get a symmetric matrix.
The Elpric node declares six variables: three scalar eigenvalues and three eigenvectors. The eigenvalues get the names using the template
<name><i>[_<suffix>] where
i is the eigenvalue number and can be 1, 2, or 3. Similarly, the eigenvector has the same name but with a
vec. prefix in front of the name. As an example, let the name be
eig and the suffix be empty. This gives the following variables:
eig1,
eig2,
eig3,
vec.eig1,
vec.eig2, and
vec.eig3. The scalar components of the first eigenvector become:
eig2x,
eig2y, and
eig2z.
) to add 
) as a subnode.