matrix.py 文件源码

def real_eig(M,eps=1e-9):
    '''
    This code expects a real hermetian matrix
    and should throw a ValueError if not.
    This is probably redundant to the scipy eigh function.
    Do not use.
    '''
    if not (type(M)==np.ndarray):
        raise ValueError("Expected array; type is %s"%type(M))
    if np.any(np.abs(np.imag(M))>eps):
        raise ValueError("Matrix has imaginary values >%0.2e; will not extract real eigenvalues"%eps)
    M = np.real(M)
    w,v = np.linalg.eig(M)
    if np.any(abs(np.imag(w))>eps):
        raise ValueError('Eigenvalues with imaginary part >%0.2e; matrix has complex eigenvalues'%eps)
    w = np.real(w)
    order = np.argsort(w)
    w = w[order]
    v = v[:,order]
    return w,v