Numba中的Python列表的基本问题；这是怎么回事? [英] Basic trouble with Python lists in Numba; what's going on?

问题描述

我是Numba的初学者.对于我的生活，我无法获得Numba函数来操作简单的列表.
哎呀，我什至不知道如何指定签名.

I'm a beginner to Numba. For the life in me I can't get a Numba function to manipulate a simple list.
Heck, I can't even figure out how to specify the signature.

这里是例子.怎么了?(什么是反射列表"?)我该如何解决?

Here's the example. What's wrong? (What's a "reflected list"?) And how do I fix it?

from numba import *
from numba.types import *

@jit(List(int64)(List(int64)), nopython=True)
def foo(a): a[0] += a[0]; return a

foo([1])

给予

Traceback (most recent call last):
  File "<pyshell#5>", in <module>
    foo([1])
  File "numba\dispatcher.py", line 219, in _explain_matching_error
    raise TypeError(msg)
TypeError: No matching definition for argument type(s) reflected list(int64)

推荐答案

我没有找到关于该主题的任何文档，但是从我浏览源代码，反射"列表是在JITted函数之后必须在Python中可见(反映)列表更改的列表完成了.由于我不知道的原因，在Numba类型系统中，反射列表被视为与非反射列表不同的类型.这个概念可能特定于nopython模式.我不确定，也无法测试.

I haven't found any documentation on the subject, but from the things that came up when I Googled the topic and dug through the source code, a "reflected" list is one where changes to the list have to be visible (reflected) in Python after a JITted function is done with it. Reflected lists are treated as a different type from non-reflected lists in the Numba type system, for reasons I do not know. The concept may be specific to nopython mode; I'm not sure, and I can't test it.

您已经声明您的函数接受一个非反射列表，但是它需要一个反射列表.您需要将 reflected = True 添加到内部的 List(int64)调用中，并且可能还要添加外部的调用.

You've declared that your function takes a non-reflected list, but it needs to take a reflected list. You need to add reflected=True to the inner List(int64) call, and possibly the outer one as well.

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