Source code for jax._src.scipy.stats.expon

# Copyright 2018 The JAX Authors.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     https://www.apache.org/licenses/LICENSE-2.0
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import scipy.stats as osp_stats

from jax import lax
import jax.numpy as jnp
from jax._src.numpy.util import implements, promote_args_inexact
from jax._src.typing import Array, ArrayLike


[docs] @implements(osp_stats.expon.logpdf, update_doc=False) def logpdf(x: ArrayLike, loc: ArrayLike = 0, scale: ArrayLike = 1) -> Array: x, loc, scale = promote_args_inexact("expon.logpdf", x, loc, scale) log_scale = lax.log(scale) linear_term = lax.div(lax.sub(x, loc), scale) log_probs = lax.neg(lax.add(linear_term, log_scale)) return jnp.where(lax.lt(x, loc), -jnp.inf, log_probs)
[docs] @implements(osp_stats.expon.pdf, update_doc=False) def pdf(x: ArrayLike, loc: ArrayLike = 0, scale: ArrayLike = 1) -> Array: return lax.exp(logpdf(x, loc, scale))