# mars.tensor.vdot¶

`mars.tensor.``vdot`(a, b)[source]

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 – Dot product of a and b. Can be an int, float, or complex depending on the types of a and b.

Return type

Tensor

`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
```