jax.numpy.max — JAX documentation (original) (raw)

jax.numpy.max#

jax.numpy.max(a, axis=None, out=None, keepdims=False, initial=None, where=None)[source]#

Return the maximum of the array elements along a given axis.

JAX implementation of numpy.max().

Parameters:

• a (ArrayLike) – Input array.
• axis (Axis) – int or array, default=None. Axis along which the maximum to be computed. If None, the maximum is computed along all the axes.
• keepdims (bool) – bool, default=False. If true, reduced axes are left in the result with size 1.
• initial (ArrayLike | None) – int or array, default=None. Initial value for the maximum.
• where (ArrayLike | None) – int or array of boolean dtype, default=None. The elements to be used in the maximum. Array should be broadcast compatible to the input.initial must be specified when where is used.
• out (None) – Unused by JAX.

Returns:

An array of maximum values along the given axis.

Return type:

Array

See also

• jax.numpy.min(): Compute the minimum of array elements along a given axis.
• jax.numpy.sum(): Compute the sum of array elements along a given axis.
• jax.numpy.prod(): Compute the product of array elements along a given axis.

Examples

By default, jnp.max computes the maximum of elements along all the axes.

x = jnp.array([[9, 3, 4, 5], ... [5, 2, 7, 4], ... [8, 1, 3, 6]]) jnp.max(x) Array(9, dtype=int32)

If axis=1, the maximum will be computed along axis 1.

jnp.max(x, axis=1) Array([9, 7, 8], dtype=int32)

If keepdims=True, ndim of the output will be same of that of the input.

jnp.max(x, axis=1, keepdims=True) Array([[9], [7], [8]], dtype=int32)

To include only specific elements in computing the maximum, you can usewhere. It can either have same dimension as input

where=jnp.array([[0, 0, 1, 0], ... [0, 0, 1, 1], ... [1, 1, 1, 0]], dtype=bool) jnp.max(x, axis=1, keepdims=True, initial=0, where=where) Array([[4], [7], [8]], dtype=int32)

or must be broadcast compatible with input.

where = jnp.array([[False], ... [False], ... [False]]) jnp.max(x, axis=0, keepdims=True, initial=0, where=where) Array([[0, 0, 0, 0]], dtype=int32)