tensorproduct.py 文件源码

def tensor_product_simp(e, **hints):
    """Try to simplify and combine TensorProducts.

    In general this will try to pull expressions inside of ``TensorProducts``.
    It currently only works for relatively simple cases where the products have
    only scalars, raw ``TensorProducts``, not ``Add``, ``Pow``, ``Commutators``
    of ``TensorProducts``. It is best to see what it does by showing examples.

    Examples
    ========

    >>> from sympy.physics.quantum import tensor_product_simp
    >>> from sympy.physics.quantum import TensorProduct
    >>> from sympy import Symbol
    >>> A = Symbol('A',commutative=False)
    >>> B = Symbol('B',commutative=False)
    >>> C = Symbol('C',commutative=False)
    >>> D = Symbol('D',commutative=False)

    First see what happens to products of tensor products:

    >>> e = TensorProduct(A,B)*TensorProduct(C,D)
    >>> e
    AxB*CxD
    >>> tensor_product_simp(e)
    (A*C)x(B*D)

    This is the core logic of this function, and it works inside, powers, sums,
    commutators and anticommutators as well:

    >>> tensor_product_simp(e**2)
    (A*C)x(B*D)**2

    """
    if isinstance(e, Add):
        return Add(*[tensor_product_simp(arg) for arg in e.args])
    elif isinstance(e, Pow):
        return tensor_product_simp(e.base) ** e.exp
    elif isinstance(e, Mul):
        return tensor_product_simp_Mul(e)
    elif isinstance(e, Commutator):
        return Commutator(*[tensor_product_simp(arg) for arg in e.args])
    elif isinstance(e, AntiCommutator):
        return AntiCommutator(*[tensor_product_simp(arg) for arg in e.args])
    else:
        return e