Moore-Penrose Matrix Inverse
Given an
matrix
, the Moore-Penrose generalized matrix inverse is a unique
matrix pseudoinverse
. This matrix was independently defined by Moore in 1920 and Penrose (1955), and variously known as the generalized inverse, pseudoinverse, or Moore-Penrose inverse. It is a matrix 1-inverse, and is implemented in the Wolfram Language as PseudoInverse[m].
The Moore-Penrose inverse satisfies
where
is the conjugate transpose.
It is also true that
 |
(5)
|
is the shortest length least squares solution to the problem
 |
(6)
|
If the inverse of
exists, then
 |
(7)
|
as can be seen by premultiplying both sides of (6) by
to create a square matrix which can then be inverted,
 |
(8)
|
giving
REFERENCES:
Ben-Israel, A. and Greville, T. N. E. Generalized Inverses: Theory and Applications. New York: Wiley, 1977.
Campbell, S. L. and Meyer, C. D. Jr. Generalized Inverses of Linear Transformations. New York: Dover, 1991.
Lawson, C. and Hanson, R. Solving Least Squares Problems. Englewood Cliffs, NJ: Prentice-Hall, 1974.
Penrose, R. "A Generalized Inverse for Matrices." Proc. Cambridge Phil. Soc. 51, 406-413, 1955.
Rao, C. R. and Mitra, S. K. Generalized Inverse of Matrices and Its Applications. New York: Wiley, 1971.