jax.numpy.expm1

jax.numpy.expm1(x, /)

Calculate exp(x)-1 of each element of the input.

JAX implementation of numpy.expm1.

Parameters:

x (ArrayLike) – input array or scalar.

Returns:

An array containing exp(x)-1 of each element in x, promotes to inexact dtype.

Return type:

Array

Note

jnp.expm1 has much higher precision than the naive computation of exp(x)-1 for small values of x.

See also

• jax.numpy.log1p(): Calculates element-wise logarithm of one plus input.

• jax.numpy.exp(): Calculates element-wise exponential of the input.

• jax.numpy.exp2(): Calculates base-2 exponential of each element of the input.

Examples

>>> x = jnp.array([2, -4, 3, -1])
>>> with jnp.printoptions(precision=2, suppress=True):
...   print(jnp.expm1(x))
[ 6.39 -0.98 19.09 -0.63]
>>> with jnp.printoptions(precision=2, suppress=True):
...   print(jnp.exp(x)-1)
[ 6.39 -0.98 19.09 -0.63]

For values very close to 0, jnp.expm1(x) is much more accurate than jnp.exp(x)-1:

>>> x1 = jnp.array([1e-4, 1e-6, 2e-10])
>>> jnp.expm1(x1)
Array([1.0000500e-04, 1.0000005e-06, 2.0000000e-10], dtype=float32)
>>> jnp.exp(x1)-1
Array([1.00016594e-04, 9.53674316e-07, 0.00000000e+00], dtype=float32)