jax.numpy.dot#

jax.numpy.dot(a, b, *, precision=None, preferred_element_type=None)[source]#

Dot product of two arrays. Specifically,

LAX-backend implementation of numpy.dot().

In addition to the original NumPy arguments listed below, also supports precision for extra control over matrix-multiplication precision on supported devices. precision may be set to None, which means default precision for the backend, a Precision enum value (Precision.DEFAULT, Precision.HIGH or Precision.HIGHEST) or a tuple of two Precision enums indicating separate precision for each argument.

Original docstring below.

  • If both a and b are 1-D arrays, it is inner product of vectors (without complex conjugation).

  • If both a and b are 2-D arrays, it is matrix multiplication, but using matmul() or a @ b is preferred.

  • If either a or b is 0-D (scalar), it is equivalent to multiply() and using numpy.multiply(a, b) or a * b is preferred.

  • If a is an N-D array and b is a 1-D array, it is a sum product over the last axis of a and b.

  • If a is an N-D array and b is an M-D array (where M>=2), it is a sum product over the last axis of a and the second-to-last axis of b:

    dot(a, b)[i,j,k,m] = sum(a[i,j,:] * b[k,:,m])

It uses an optimized BLAS library when possible (see numpy.linalg).

Parameters:

  • a (array_like) – First argument.

  • b (array_like) – Second argument.

  • preferred_element_type (dtype, optional) – If specified, accumulate results and return a result of the given data type. If not specified, the accumulation dtype is determined from the type promotion rules of the input array dtypes.

  • precision (PrecisionLike) –

Returns:

output – Returns the dot product of a and b. If a and b are both scalars or both 1-D arrays then a scalar is returned; otherwise an array is returned. If out is given, then it is returned.

Return type:

ndarray