
A command to project the columns of the Matrix object onto the eigenspace of the Eigen object.
Project each column of the Matrix on the coordinate system given by the eigenvectors of the Eigen object. This can be done as follows:
y_{ij} = Σ_{k=1..dimension} e_{ik} z_{kj}, where 
y_{ij} is the jth element of the ith row of the result, e_{ik} is the kth element of the ith eigenvector, z_{kj} is the kth element of the jth column of the selected Matrix object, and dimension is the number of elements in an eigenvector.
© djmw, February 23, 2016