The data resolution is known to be related to the operator
_data = M(M^T)^M^T. Substituting (inversionop) for the pseudoinverse and then defining
q_i Mp_i, we find that the resolution operator for the data space is
_data = _i=1^n q_iq_i^T (q_i,q_i), a form completely analogous to that in (RmodelCG).