Have a question? Connect with the community at the TensorFlow Forum Visit Forum


Assert tensor shapes and dimension size relationships between tensors.

This Op checks that a collection of tensors shape relationships satisfies given constraints.


n = 10
q = 3
d = 7
x = tf.zeros([n,q])
y = tf.ones([n,d])
param = tf.Variable([1.0, 2.0, 3.0])
scalar = 1.0
 (x, ('N', 'Q')),
 (y, ('N', 'D')),
 (param, ('Q',)),
 (scalar, ()),
  (x, ('N', 'D')),
  (y, ('N', 'D'))
Traceback (most recent call last):

ValueError: ...

Example of adding a dependency to an operation:

with tf.control_dependencies([tf.assert_shapes(shapes)]):
  output = tf.matmul(x, y, transpose_a=True)

If x, y, param or scalar does not have a shape that satisfies all specified constraints, message, as well as the first summarize entries of the first encountered violating tensor are printed, and InvalidArgumentError is raised.

Size entries in the specified shapes are checked against other entries by their hash, except:

  • a size entry is interpreted as an explicit size if it can be parsed as an integer primitive.
  • a size entry is interpreted as any size if it is None or '.'.

If the first entry of a shape is ... (type Ellipsis) or '*' that indicates a variable number of outer dimensions of unspecified size, i.e. the constraint applies to the inner-most dimensions only.

Scalar tensors and specified shapes of length zero (excluding the 'inner-most' prefix) are both treated as having a single dimension of size one.

shapes A list of (Tensor, shape) tuples, wherein shape is the expected shape of Tensor. See the example code above. The shape must be an iterable. Each element of the iterable can be either a concrete integer value or a string that abstractly represents the dimension. For example,

  • ('N', 'Q') specifies a 2D shape wherein the first and second dimensions of shape may or may not be equal.
  • ('N', 'N', 'Q') specifies a 3D shape wherein the first and second dimensions are equal.
  • (1, 'N') specifies a 2D shape wherein the first dimension is exactly 1 and the second dimension can be any value. Note that the abstract dimension letters take effect across different tuple elements of the list. For example, tf.debugging.assert_shapes([(x, ('N', 'A')), (y, ('N', 'B'))] asserts that both x and y are rank-2 tensors and their first dimensions are equal (N). shape can also be a tf.TensorShape.
data The tensors to print out if the condition is False. Defaults to error message and first few entries of the violating tensor.
summarize Print this many entries of the tensor.
message A string to prefix to the default message.
name A name for this operation (optional). Defaults to "assert_shapes".

Op raising InvalidArgumentError unless all shape constraints are satisfied. If static checks determine all constraints are satisfied, a no_op is returned.

ValueError If static checks determine any shape constraint is violated.