pinv(a, rcond=1e-15, hermitian=False)¶
Compute the (Moore-Penrose) pseudo-inverse of a matrix.
Calculate the generalized inverse of a matrix using its singular-value decomposition (SVD) and including all large singular values.
Changed in version 1.14: Can now operate on stacks of matrices
- a(…, M, N) array_like
Matrix or stack of matrices to be pseudo-inverted.
- rcond(…) array_like of float
Cutoff for small singular values. Singular values less than or equal to
rcond * largest_singular_valueare set to zero. Broadcasts against the stack of matrices.
- hermitianbool, optional
If True, a is assumed to be Hermitian (symmetric if real-valued), enabling a more efficient method for finding singular values. Defaults to False.
New in version 1.17.0.
- B(…, N, M) ndarray
The pseudo-inverse of a. If a is a matrix instance, then so is B.
If the SVD computation does not converge.
The pseudo-inverse of a matrix A, denoted , is defined as: “the matrix that ‘solves’ [the least-squares problem] ,” i.e., if is said solution, then is that matrix such that .
It can be shown that if is the singular value decomposition of A, then , where are orthogonal matrices, is a diagonal matrix consisting of A’s so-called singular values, (followed, typically, by zeros), and then is simply the diagonal matrix consisting of the reciprocals of A’s singular values (again, followed by zeros). 
G. Strang, Linear Algebra and Its Applications, 2nd Ed., Orlando, FL, Academic Press, Inc., 1980, pp. 139-142.
The following example checks that
a * a+ * a == aand
a+ * a * a+ == a+:
>>> a = np.random.randn(9, 6) >>> B = np.linalg.pinv(a) >>> np.allclose(a, np.dot(a, np.dot(B, a))) True >>> np.allclose(B, np.dot(B, np.dot(a, B))) True