如何用JAX打印

Question

我有一个JAX布尔数组，并希望打印一个与_True_s之和相结合的语句：

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()

在_True_s中有5个mask_cp；我想将其打印为：

With jax accelerator
There are 5 true bools

因为这个函数是弹跳，所以我试着用id_print打印它，但是我没有。id_print(jnp.sum(mask_cp))会打印5，但是不能在字符串中使用它。我试过以下几种方法：

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。尽管如此，我不认为id_print有能力添加这样的文本，但是您可以通过一个更通用的host_callback.call来实现它

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()

输出是

There are 5 true bools