text: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  # Copyright 1999-2020 Alibaba Group Holding Ltd.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from ..datasource import tensor as astensor
  from .dot import dot
  
  
  def vdot(a, b):
      """
      Return the dot product of two vectors.
  
      The vdot(`a`, `b`) function handles complex numbers differently than
      dot(`a`, `b`).  If the first argument is complex the complex conjugate
      of the first argument is used for the calculation of the dot product.
  
      Note that `vdot` handles multidimensional tensors differently than `dot`:
      it does *not* perform a matrix product, but flattens input arguments
      to 1-D vectors first. Consequently, it should only be used for vectors.
  
      Parameters
      ----------
      a : array_like
          If `a` is complex the complex conjugate is taken before calculation
          of the dot product.
      b : array_like
          Second argument to the dot product.
  
      Returns
      -------
      output : Tensor
          Dot product of `a` and `b`.  Can be an int, float, or
          complex depending on the types of `a` and `b`.
  
      See Also
      --------
      dot : Return the dot product without using the complex conjugate of the
            first argument.
  
      Examples
      --------
      >>> import mars.tensor as mt
  
      >>> a = mt.array([1+2j,3+4j])
      >>> b = mt.array([5+6j,7+8j])
      >>> mt.vdot(a, b).execute()
      (70-8j)
      >>> mt.vdot(b, a).execute()
      (70+8j)
  
      Note that higher-dimensional arrays are flattened!
  
      >>> a = mt.array([[1, 4], [5, 6]])
      >>> b = mt.array([[4, 1], [2, 2]])
      >>> mt.vdot(a, b).execute()
      30
      >>> mt.vdot(b, a).execute()
      30
      >>> 1*4 + 4*1 + 5*2 + 6*2
      30
      """
      a, b = astensor(a), astensor(b)
      return dot(a.conj().ravel(), b.ravel())
  