TensorFlow 1 version | View source on GitHub |
Computes the sum of elements across dimensions of a tensor.
tf.math.reduce_sum(
input_tensor, axis=None, keepdims=False, name=None
)
Used in the notebooks
Used in the guide | Used in the tutorials |
---|---|
Reduces input_tensor
along the dimensions given in axis
.
Unless keepdims
is true, the rank of the tensor is reduced by 1 for each
of the entries in axis
, which must be unique. If keepdims
is true, the
reduced dimensions are retained with length 1.
If axis
is None, all dimensions are reduced, and a
tensor with a single element is returned.
For example:
# x has a shape of (2, 3) (two rows and three columns):
x = tf.constant([[1, 1, 1], [1, 1, 1]])
x.numpy()
array([[1, 1, 1],
[1, 1, 1]], dtype=int32)
# sum all the elements
# 1 + 1 + 1 + 1 + 1+ 1 = 6
tf.reduce_sum(x).numpy()
6
# reduce along the first dimension
# the result is [1, 1, 1] + [1, 1, 1] = [2, 2, 2]
tf.reduce_sum(x, 0).numpy()
array([2, 2, 2], dtype=int32)
# reduce along the second dimension
# the result is [1, 1] + [1, 1] + [1, 1] = [3, 3]
tf.reduce_sum(x, 1).numpy()
array([3, 3], dtype=int32)
# keep the original dimensions
tf.reduce_sum(x, 1, keepdims=True).numpy()
array([[3],
[3]], dtype=int32)
# reduce along both dimensions
# the result is 1 + 1 + 1 + 1 + 1 + 1 = 6
# or, equivalently, reduce along rows, then reduce the resultant array
# [1, 1, 1] + [1, 1, 1] = [2, 2, 2]
# 2 + 2 + 2 = 6
tf.reduce_sum(x, [0, 1]).numpy()
6
Args | |
---|---|
input_tensor
|
The tensor to reduce. Should have numeric type. |
axis
|
The dimensions to reduce. If None (the default), reduces all
dimensions. Must be in the range [-rank(input_tensor),
rank(input_tensor)] .
|
keepdims
|
If true, retains reduced dimensions with length 1. |
name
|
A name for the operation (optional). |
Returns | |
---|---|
The reduced tensor, of the same dtype as the input_tensor. |
Numpy Compatibility
Equivalent to np.sum apart the fact that numpy upcast uint8 and int32 to int64 while tensorflow returns the same dtype as the input.