scipy.linalg.cosm

scipy.linalg.cosm(A)

Compute the matrix cosine.

This routine uses expm to compute the matrix exponentials.

Parameters:

A : (N, N) array_like

Input array

Returns:

cosm : (N, N) ndarray

Matrix cosine of A

Examples

>>> from scipy.linalg import expm, sinm, cosm

Euler’s identity (exp(i*theta) = cos(theta) + i*sin(theta)) applied to a matrix:

>>> a = np.array([[1.0, 2.0], [-1.0, 3.0]])
>>> expm(1j*a)
array([[ 0.42645930+1.89217551j, -2.13721484-0.97811252j],
       [ 1.06860742+0.48905626j, -1.71075555+0.91406299j]])
>>> cosm(a) + 1j*sinm(a)
array([[ 0.42645930+1.89217551j, -2.13721484-0.97811252j],
       [ 1.06860742+0.48905626j, -1.71075555+0.91406299j]])