mtimes

Lag operator polynomial multiplication

Syntax

C = mtimes(A, B, 'Tolerance',tolerance)
C = A * B

Description

Given two lag operator polynomials A(L) and B(L),C = mtimes(A, B, 'Tolerance',tolerance) performs a polynomial multiplication C(L) = A(L) * B(L). If at least one of A or B is a lag operator polynomial object, the other can be a cell array of matrices (initial lag operator coefficients), or a single matrix (zero-degree lag operator). 'Tolerance' is the nonnegative scalar tolerance used to determine which coefficients are included in the result. The default tolerance is 1e-12. Specifying a tolerance greater than 0 allows the user to exclude polynomial lags with near-zero coefficients. A coefficient matrix of a given lag is excluded only if the magnitudes of all elements of the matrix are less than or equal to the specified tolerance.

C = A * B performs a polynomial multiplication C(L) = A(L) * B(L).

Examples

expand all

Create two LagOp polynomials and multiply them together:

A = LagOp({1 -0.6 0.08});
B = LagOp({1 -0.5});
mtimes(A,B)
ans =
1-D Lag Operator Polynomial:
-----------------------------
Coefficients: [1 -1.1 0.38 -0.04]
Lags: [0 1 2 3]
Degree: 3
Dimension: 1

Tips

The multiplication operator (*) invokes mtimes, but the optional coefficient tolerance is available only by calling mtimes directly.