scipy.sparse
scipy.sparse.linalg.LinearOperator.adjoint
scipy.sparse.linalg.LinearOperator.matmat
LinearOperator.
dot
Matrix-matrix or matrix-vector multiplication.
x : array_like
1-d or 2-d array, representing a vector or matrix.
Ax : array
1-d or 2-d array (depending on the shape of x) that represents the result of applying this linear operator on x.