numpy错误:电源中遇到无效值 [英] Numpy error: invalid value encountered in power
问题描述
我有以下代码:
import numpy
def numpysum(n):
a = numpy.arange(n) ** 2
b = numpy.arange(n) ** 3
c = a + b
return c
size = 3000
c = numpysum(size)
运行时出现错误:
D:\ Work \ programming \ python \ test_1 \ src \ test1_numpy.py:6:RuntimeWarning:电源遇到无效值 b = numpy.arange(n)** 3
D:\Work\programming\python\test_1\src\test1_numpy.py:6: RuntimeWarning: invalid value encountered in power b = numpy.arange(n) ** 3
请注意,以下numpyless函数可以正常工作:
Note that the following numpyless function works fine:
def pythonsum(n):
a = list(range(n))
b = list(range(n))
c = []
for i in range(len(a)):
a[i] = i ** 2
b[i] = i ** 3
c.append(a[i] + b[i])
return c
我想这是因为我试图筹集大量资金以支持三.除了处理浮点数外,我还能做什么?
I guess it happens because I try to raise a large number to power three. What can I do, beside working with floating point numbers?
我正在使用Python 3.2.
I am working with Python 3.2.
推荐答案
numpy实际上正在为此上寻找您.与标准Python不同,其整数运算不适用于任意精度的对象.我猜您正在运行32位python,因为相同的操作对我而言不会溢出:
numpy is actually looking out for you on this one. Unlke in standard Python, its integer operations don't work on arbitrary-precision objects. I'd guess you were running a 32-bit python, because the same operations don't overflow for me:
>>> sys.maxsize
9223372036854775807
>>> size = 3000
>>> c = numpysum(size)
>>>
但是他们最终会.甚至更容易了解您是否手动控制类型的大小:
but they will eventually. Even easier to see if you control the size of the type manually:
>>> numpy.arange(10, dtype=numpy.int8)**10
__main__:1: RuntimeWarning: invalid value encountered in power
array([ 0, 1, 0, -87, 0, -7, 0, -15, 0, 0], dtype=int8)
>>> numpy.arange(10, dtype=numpy.int16)**10
array([ 0, 1, 1024, -6487, 0, 761, -23552, 15089,
0, 0], dtype=int16)
>>> numpy.arange(10, dtype=numpy.int32)**10
array([ 0, 1, 1024, 59049, 1048576,
9765625, 60466176, 282475249, 1073741824, -2147483648], dtype=int32)
>>> numpy.arange(10, dtype=numpy.int64)**10
array([ 0, 1, 1024, 59049, 1048576,
9765625, 60466176, 282475249, 1073741824, 3486784401])
随着位数的增加,情况会有所改善.如果您确实希望对Python任意大小的整数执行numpy数组操作,则可以将dtype设置为object:
where things improve as the number of bits increases. If you really want numpy array operations on Python arbitrary-size integers, you can set dtype to object:
>>> numpy.arange(10, dtype=object)**20
array([0, 1, 1048576, 3486784401, 1099511627776, 95367431640625,
3656158440062976, 79792266297612001, 1152921504606846976,
12157665459056928801], dtype=object)
这篇关于numpy错误:电源中遇到无效值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!