We give simple formulas for the canonical metric, gradient, Lie derivative, Riemannian connection, parallel translation, geodesics and distance on the Grassmann manifold of
p-planes in
R
n
. In these formulas,
p-planes are represented as the column space of
n×
p matrices. The Newton method on abstract Riemannian manifolds proposed by Smith is made explicit on the Grassmann manifold. Two applications – computing an invariant subspace of a matrix and the mean of subspaces – are worked out.
Grassmann manifold - noncompact Stiefel manifold - principal fiber bundle - Levi-Civita connection - parallel transportation - geodesic - Newton method - invariant subspace - mean of subspaces