corewise_stack_dot
==================

.. py:function:: t3toolbox.corewise.corewise_stack_dot(X, Y, n_stack)

   .. code-block:: python

      def corewise_stack_dot(
              X:          NDArrayTree,  # tree; each leaf shape = stack_shape + (core dims)
              Y:          NDArrayTree,  # same tree structure / leaf shapes as X
              n_stack:    int,          # number of leading stack axes kept (contract the rest)
      ) -> NDArray:  # array of shape = common stack_shape (scalar when n_stack==0)


   Like corewise_dot, but vectorized over the leading ``n_stack`` (stack) axes.

   Each leaf is contracted over its trailing (non-stack) axes only, keeping the leading ``n_stack``
   axes, and the per-leaf results are summed. Returns an array of shape equal to the common leading
   stack shape (a scalar when ``n_stack == 0``, matching :py:func:`corewise_dot`).

   .. rubric:: Examples

   >>> import numpy as np
   >>> import t3toolbox.corewise as cw
   >>> X = (np.ones((2, 3)), np.ones((2, 4, 5)))   # stack=(2,), then core axes
   >>> Y = (2*np.ones((2, 3)), np.ones((2, 4, 5)))
   >>> print(cw.corewise_stack_dot(X, Y, 1))       # per-stack-slice: 2*3 + 4*5 = 26
   [26. 26.]