linalg.py 文件源码

def _eig_leftvec_add_mps(lv, lt1, lt2):
    """Add one column to the left vector (MPS version)"""
    # MPS 1: Interpreted as |psiXpsi| part of the operator
    # MPS 2: The current eigvectector candidate
    # NB: It would be more efficient to store lt1.conj() instead of lt1.
    # lv axes: 0: mps1 bond, 1: mps2 bond
    lv = np.tensordot(lv, lt1.conj(), axes=(0, 0))
    # lv axes: 0: mps2 bond, 1: physical leg, 2: mps1 bond
    lv = np.tensordot(lv, lt2, axes=((0, 1), (0, 1)))
    # lv axes: 0: mps1 bond, 1: mps2 bond
    return lv