如何使用 JAX 进行打印

Question

我有一个 JAX 布尔数组，想打印一个语句结合 Trues:

import jax
import jax.numpy as jnp
from jax.experimental.host_callback import id_print

@jax.jit
def overlaps_jax():
    mask_cp = jnp.array([True, False, False, True, False, True, False, True, True])
    id_print(jnp.sum(mask_cp))

overlaps_jax()

mask_cp中有5个True；我想打印为：

With jax accelerator
There are 5 true bools

因为这个函数是jitted, I tried to print this by using id_print，但是我做不到。 id_print(jnp.sum(mask_cp)) 将打印 5，但我无法将其用于字符串。我尝试了以下方法：

id_print(jnp.sum(mask_cp))
# print:
# 5

id_print("\nWith jax accelerator\nThere are " + jnp.sum(mask_cp) + " true bools\n")
# error:
# TypeError: can only concatenate str (not "DynamicJaxprTracer") to str

print("\nWith jax accelerator\nThere are {} true bools\n".format(jnp.sum(mask_cp)))
# print:
# With jax accelerator
# There are Traced<ShapedArray(int64[])>with<DynamicJaxprTrace(level=0/1)> true bools

如何在这段代码中打印这样的语句？

Answer 1

请注意 id_print 是实验性的，其 API 和功能可能会发生变化。也就是说，我不相信 id_print 有能力添加这样的文本，但你可以通过更通用的 host_callback.call:

import jax
import jax.numpy as jnp
from jax.experimental.host_callback import call

@jax.jit
def overlaps_jax():
    mask_cp = jnp.array([True, False, False, True, False, True, False, True, True])
    call(lambda x: print(f"There are {x} true bools"), jnp.sum(mask_cp))

overlaps_jax()

输出为

There are 5 true bools

如何使用 JAX 进行打印

How to print with JAX

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