Estimate the envelope subspace with specified dimension.
envMU(M, U, u)
M matrix in the envelope objective function. An r by r semi-positive definite matrix.
U matrix in the envelope objective function. An r by r semi-positive definite matrix.
Dimension of the envelope. An integer between 0 and r.
The orthonormal basis of the envelope subspace.
The orthonormal basis of the complement of the envelope subspace.
The minimized objective function.
This function estimate the envelope subspace using an non-Grassmann optimization algorithm. The starting value and optimization algorithm is described in Cook et al. (2016).
Cook, R. D., Forzani, L. and Su, Z. (2016) A Note on Fast Envelope Estimation. Journal of Multivariate Analysis. 150, 42-54.