映射一个NumPy数组

时间:2021-07-22 21:46:52

Is it possible to map a NumPy array in place? If yes, how?

是否有可能映射一个NumPy数组?如果是,如何?

Given a_values - 2D array - this is the bit of code that does the trick for me at the moment:

给定一个a_values—2D数组—这段代码现在对我很有用:

for row in range(len(a_values)):
    for col in range(len(a_values[0])):
        a_values[row][col] = dim(a_values[row][col])

But it's so ugly that I suspect that somewhere within NumPy there must be a function that does the same with something looking like:

但它太丑了,我怀疑在NumPy中一定有一个函数,它的作用和它类似:

a_values.map_in_place(dim)

but if something like the above exists, I've been unable to find it.

但是,如果像上面这样的东西存在,我就找不到它了。

5 个解决方案

#1


49  

It's only worth trying to do this in-place if you are under significant space constraints. If that's the case, it is possible to speed up your code a little bit by iterating over a flattened view of the array. Since reshape returns a new view when possible, the data itself isn't copied (unless the original has unusual structure).

只有当您处于严重的空间限制时,才值得尝试在适当的位置上执行此操作。如果是这种情况,那么可以通过遍历数组的平面化视图来加快代码的速度。因为在可能的情况下,“重塑”返回一个新的视图,所以数据本身不会被复制(除非原始的视图具有不同寻常的结构)。

I don't know of a better way to achieve bona fide in-place application of an arbitrary Python function.

我不知道有什么更好的方法来实现任意Python函数的就地应用程序。

>>> def flat_for(a, f):
...     a = a.reshape(-1)
...     for i, v in enumerate(a):
...         a[i] = f(v)
... 
>>> a = numpy.arange(25).reshape(5, 5)
>>> flat_for(a, lambda x: x + 5)
>>> a

array([[ 5,  6,  7,  8,  9],
       [10, 11, 12, 13, 14],
       [15, 16, 17, 18, 19],
       [20, 21, 22, 23, 24],
       [25, 26, 27, 28, 29]])

Some timings:

一些时间:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> f = lambda x: x + 5
>>> %timeit flat_for(a, f)
1000 loops, best of 3: 1.86 ms per loop

It's about twice as fast as the nested loop version:

它的速度是嵌套循环版本的两倍:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> def nested_for(a, f):
...     for i in range(len(a)):
...         for j in range(len(a[0])):
...             a[i][j] = f(a[i][j])
... 
>>> %timeit nested_for(a, f)
100 loops, best of 3: 3.79 ms per loop

Of course vectorize is still faster, so if you can make a copy, use that:

当然,vectorize还是比较快的,所以如果你可以复制一份,可以这样做:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> g = numpy.vectorize(lambda x: x + 5)
>>> %timeit g(a)
1000 loops, best of 3: 584 us per loop

And if you can rewrite dim using built-in ufuncs, then please, please, don't vectorize:

如果你能用内置的ufuncs重写dim,那么,请不要向量化:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> %timeit a + 5
100000 loops, best of 3: 4.66 us per loop

numpy does operations like += in place, just as you might expect -- so you can get the speed of a ufunc with in-place application at no cost. Sometimes it's even faster! See here for an example.

numpy执行像+=这样的操作,正如您所期望的那样,因此您可以以无成本的方式获得ufunc的速度。有时甚至更快!请看这里的一个例子。


By the way, my original answer to this question, which can be viewed in its edit history, is ridiculous, and involved vectorizing over indices into a. Not only did it have to do some funky stuff to bypass vectorize's type-detection mechanism, it turned out to be just as slow as the nested loop version. So much for cleverness!

顺便说一下,我原来对这个问题的回答,可以在其编辑历史,是荒谬的,和涉及vectorizing指数成。不仅它必须做一些时髦的东西绕过的类型声明机制,结果是一样缓慢的嵌套循环的版本。那么多聪明!

#2


44  

This is a write-up of contributions scattered in answers and comments, that I wrote after accepting the answer to the question. Upvotes are always welcome, but if you upvote this answer, please don't miss to upvote also those of senderle and (if (s)he writes one) eryksun, who suggested the methods below.

这是我在接受这个问题的答案后写的一篇关于各种答案和评论的文章。upvote总是受欢迎的,但是如果你投票赞成这个答案,请不要错过投票,也不要错过senderle和(如果他写了一个),他建议下面的方法。

Q: Is it possible to map a numpy array in place?
A: Yes but not with a single array method. You have to write your own code.

问:有可能映射一个numpy数组吗?答:是的,但不是用单一的数组方法。您必须编写自己的代码。

Below a script that compares the various implementations discussed in the thread:

下面的脚本比较线程中讨论的各种实现:

import timeit
from numpy import array, arange, vectorize, rint

# SETUP
get_array = lambda side : arange(side**2).reshape(side, side) * 30
dim = lambda x : int(round(x * 0.67328))

# TIMER
def best(fname, reps, side):
    global a
    a = get_array(side)
        t = timeit.Timer('%s(a)' % fname,
                     setup='from __main__ import %s, a' % fname)
    return min(t.repeat(reps, 3))  #low num as in place --> converge to 1

# FUNCTIONS
def mac(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])

def mac_two(array_):
    li = range(len(array_[0]))
    for row in range(len(array_)):
        for col in li:
            array_[row][col] = int(round(array_[row][col] * 0.67328))

def mac_three(array_):
    for i, row in enumerate(array_):
        array_[i][:] = [int(round(v * 0.67328)) for v in row]


def senderle(array_):
    array_ = array_.reshape(-1)
    for i, v in enumerate(array_):
        array_[i] = dim(v)

def eryksun(array_):
    array_[:] = vectorize(dim)(array_)

def ufunc_ed(array_):
    multiplied = array_ * 0.67328
    array_[:] = rint(multiplied)

# MAIN
r = []
for fname in ('mac', 'mac_two', 'mac_three', 'senderle', 'eryksun', 'ufunc_ed'):
    print('\nTesting `%s`...' % fname)
    r.append(best(fname, reps=50, side=50))
    # The following is for visually checking the functions returns same results
    tmp = get_array(3)
    eval('%s(tmp)' % fname)
    print tmp
tmp = min(r)/100
print('\n===== ...AND THE WINNER IS... =========================')
print('  mac (as in question)       :  %.4fms [%.0f%%]') % (r[0]*1000,r[0]/tmp)
print('  mac (optimised)            :  %.4fms [%.0f%%]') % (r[1]*1000,r[1]/tmp)
print('  mac (slice-assignment)     :  %.4fms [%.0f%%]') % (r[2]*1000,r[2]/tmp)
print('  senderle                   :  %.4fms [%.0f%%]') % (r[3]*1000,r[3]/tmp)
print('  eryksun                    :  %.4fms [%.0f%%]') % (r[4]*1000,r[4]/tmp)
print('  slice-assignment w/ ufunc  :  %.4fms [%.0f%%]') % (r[5]*1000,r[5]/tmp)
print('=======================================================\n')

The output of the above script - at least in my system - is:

上述脚本的输出(至少在我的系统中)是:

  mac (as in question)       :  88.7411ms [74591%]
  mac (optimised)            :  86.4639ms [72677%]
  mac (slice-assignment)     :  79.8671ms [67132%]
  senderle                   :  85.4590ms [71832%]
  eryksun                    :  13.8662ms [11655%]
  slice-assignment w/ ufunc  :  0.1190ms [100%]

As you can observe, using numpy's ufunc increases speed of more than 2 and almost 3 orders of magnitude compared with the second best and worst alternatives respectively.

正如你所看到的,使用numpy的ufunc可以使速度比第二好的和最差的分别提高2和3个数量级。

If using ufunc is not an option, here's a comparison of the other alternatives only:

如果使用ufunc不是一种选择,这里只是对其他选择的比较:

  mac (as in question)       :  91.5761ms [672%]
  mac (optimised)            :  88.9449ms [653%]
  mac (slice-assignment)     :  80.1032ms [588%]
  senderle                   :  86.3919ms [634%]
  eryksun                    :  13.6259ms [100%]

HTH!

HTH !

#3


3  

Why not using numpy implementation, and the out_ trick ?

为什么不使用numpy实现和out_诀窍呢?

from numpy import array, arange, vectorize, rint, multiply, round as np_round 

def fmilo(array_):
    np_round(multiply(array_ ,0.67328, array_), out=array_)

got:

有:

===== ...AND THE WINNER IS... =========================
  mac (as in question)       :  80.8470ms [130422%]
  mac (optimised)            :  80.2400ms [129443%]
  mac (slice-assignment)     :  75.5181ms [121825%]
  senderle                   :  78.9380ms [127342%]
  eryksun                    :  11.0800ms [17874%]
  slice-assignment w/ ufunc  :  0.0899ms [145%]
  fmilo                      :  0.0620ms [100%]
=======================================================

#4


2  

if ufuncs are not possible, you should maybe consider using cython. it is easy to integrate and give big speedups on specific use of numpy arrays.

如果ufuncs是不可能的,您也许应该考虑使用cython。对numpy数组的特定使用进行集成和加速是很容易的。

#5


0  

This is just an updated version of mac's write-up, actualized for Python 3.x, and with numba and numpy.frompyfunc added.

这只是mac的更新版本,针对Python 3实现。加上numba和numpi .frompyfunc。

numpy.frompyfunc takes an abitrary python function and returns a function, which when cast on a numpy.array, applies the function elementwise.
However, it changes the datatype of the array to object, so it is not in place, and future calculations on this array will be slower.
To avoid this drawback, in the test numpy.ndarray.astype will be called, returning the datatype to int.

As side note:
Numba isn't included in Python's basic libraries and has to be downloaded externally if you want to test it. In this test, it actually does nothing, and if it would have been called with @jit(nopython=True), it would have given an error message saying that it can't optimize anything there. Since, however, numba can often speed-up code written in a functional style, it is included for integrity.

从pyfunc获取一个abitrary python函数并返回一个函数,在向numpy强制转换时返回一个函数。数组,应用函数elementwise。但是,它将数组的数据类型更改为object,因此不存在,对该数组的未来计算将会更慢。为了避免这个缺点,请在test numpi .ndarray中进行测试。将调用astype,将数据类型返回给int.注意:Numba不包括在Python的基本库中,如果您想测试它,必须从外部下载。在这个测试中,它实际上什么都不做,如果用@jit(nopython=True)调用它,它会给出一条错误消息,说它不能在那里优化任何东西。但是,由于numba通常可以加速用函数样式编写的代码,因此它包含在完整性中。

import timeit
from numpy import array, arange, vectorize, rint, frompyfunc
from numba import autojit

# SETUP
get_array = lambda side : arange(side**2).reshape(side, side) * 30
dim = lambda x : int(round(x * 0.67328))

# TIMER
def best(fname, reps, side):
    global a
    a = get_array(side)
    t = timeit.Timer('%s(a)' % fname,
                     setup='from __main__ import %s, a' % fname)
    return min(t.repeat(reps, 3))  #low num as in place --> converge to 1

# FUNCTIONS
def mac(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])

def mac_two(array_):
    li = range(len(array_[0]))
    for row in range(len(array_)):
        for col in li:
            array_[row][col] = int(round(array_[row][col] * 0.67328))

def mac_three(array_):
    for i, row in enumerate(array_):
        array_[i][:] = [int(round(v * 0.67328)) for v in row]


def senderle(array_):
    array_ = array_.reshape(-1)
    for i, v in enumerate(array_):
        array_[i] = dim(v)

def eryksun(array_):
    array_[:] = vectorize(dim)(array_)

@autojit
def numba(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])


def ufunc_ed(array_):
    multiplied = array_ * 0.67328
    array_[:] = rint(multiplied)

def ufunc_frompyfunc(array_):
    udim = frompyfunc(dim,1,1)
    array_ = udim(array_)
    array_.astype("int")

# MAIN
r = []
totest = ('mac', 'mac_two', 'mac_three', 'senderle', 'eryksun', 'numba','ufunc_ed','ufunc_frompyfunc')
for fname in totest:
    print('\nTesting `%s`...' % fname)
    r.append(best(fname, reps=50, side=50))
    # The following is for visually checking the functions returns same results
    tmp = get_array(3)
    eval('%s(tmp)' % fname)
    print (tmp)
tmp = min(r)/100
results = list(zip(totest,r))
results.sort(key=lambda x: x[1])

print('\n===== ...AND THE WINNER IS... =========================')
for name,time in results:
    Out = '{:<34}: {:8.4f}ms [{:5.0f}%]'.format(name,time*1000,time/tmp)
    print(Out)
print('=======================================================\n')



And finally, the results:

最后,结果:

===== ...AND THE WINNER IS... =========================
ufunc_ed                          :   0.3205ms [  100%]
ufunc_frompyfunc                  :   3.8280ms [ 1194%]
eryksun                           :   3.8989ms [ 1217%]
mac_three                         :  21.4538ms [ 6694%]
senderle                          :  22.6421ms [ 7065%]
mac_two                           :  24.6230ms [ 7683%]
mac                               :  26.1463ms [ 8158%]
numba                             :  27.5041ms [ 8582%]
=======================================================

#1


49  

It's only worth trying to do this in-place if you are under significant space constraints. If that's the case, it is possible to speed up your code a little bit by iterating over a flattened view of the array. Since reshape returns a new view when possible, the data itself isn't copied (unless the original has unusual structure).

只有当您处于严重的空间限制时,才值得尝试在适当的位置上执行此操作。如果是这种情况,那么可以通过遍历数组的平面化视图来加快代码的速度。因为在可能的情况下,“重塑”返回一个新的视图,所以数据本身不会被复制(除非原始的视图具有不同寻常的结构)。

I don't know of a better way to achieve bona fide in-place application of an arbitrary Python function.

我不知道有什么更好的方法来实现任意Python函数的就地应用程序。

>>> def flat_for(a, f):
...     a = a.reshape(-1)
...     for i, v in enumerate(a):
...         a[i] = f(v)
... 
>>> a = numpy.arange(25).reshape(5, 5)
>>> flat_for(a, lambda x: x + 5)
>>> a

array([[ 5,  6,  7,  8,  9],
       [10, 11, 12, 13, 14],
       [15, 16, 17, 18, 19],
       [20, 21, 22, 23, 24],
       [25, 26, 27, 28, 29]])

Some timings:

一些时间:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> f = lambda x: x + 5
>>> %timeit flat_for(a, f)
1000 loops, best of 3: 1.86 ms per loop

It's about twice as fast as the nested loop version:

它的速度是嵌套循环版本的两倍:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> def nested_for(a, f):
...     for i in range(len(a)):
...         for j in range(len(a[0])):
...             a[i][j] = f(a[i][j])
... 
>>> %timeit nested_for(a, f)
100 loops, best of 3: 3.79 ms per loop

Of course vectorize is still faster, so if you can make a copy, use that:

当然,vectorize还是比较快的,所以如果你可以复制一份,可以这样做:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> g = numpy.vectorize(lambda x: x + 5)
>>> %timeit g(a)
1000 loops, best of 3: 584 us per loop

And if you can rewrite dim using built-in ufuncs, then please, please, don't vectorize:

如果你能用内置的ufuncs重写dim,那么,请不要向量化:

>>> a = numpy.arange(2500).reshape(50, 50)
>>> %timeit a + 5
100000 loops, best of 3: 4.66 us per loop

numpy does operations like += in place, just as you might expect -- so you can get the speed of a ufunc with in-place application at no cost. Sometimes it's even faster! See here for an example.

numpy执行像+=这样的操作,正如您所期望的那样,因此您可以以无成本的方式获得ufunc的速度。有时甚至更快!请看这里的一个例子。


By the way, my original answer to this question, which can be viewed in its edit history, is ridiculous, and involved vectorizing over indices into a. Not only did it have to do some funky stuff to bypass vectorize's type-detection mechanism, it turned out to be just as slow as the nested loop version. So much for cleverness!

顺便说一下,我原来对这个问题的回答,可以在其编辑历史,是荒谬的,和涉及vectorizing指数成。不仅它必须做一些时髦的东西绕过的类型声明机制,结果是一样缓慢的嵌套循环的版本。那么多聪明!

#2


44  

This is a write-up of contributions scattered in answers and comments, that I wrote after accepting the answer to the question. Upvotes are always welcome, but if you upvote this answer, please don't miss to upvote also those of senderle and (if (s)he writes one) eryksun, who suggested the methods below.

这是我在接受这个问题的答案后写的一篇关于各种答案和评论的文章。upvote总是受欢迎的,但是如果你投票赞成这个答案,请不要错过投票,也不要错过senderle和(如果他写了一个),他建议下面的方法。

Q: Is it possible to map a numpy array in place?
A: Yes but not with a single array method. You have to write your own code.

问:有可能映射一个numpy数组吗?答:是的,但不是用单一的数组方法。您必须编写自己的代码。

Below a script that compares the various implementations discussed in the thread:

下面的脚本比较线程中讨论的各种实现:

import timeit
from numpy import array, arange, vectorize, rint

# SETUP
get_array = lambda side : arange(side**2).reshape(side, side) * 30
dim = lambda x : int(round(x * 0.67328))

# TIMER
def best(fname, reps, side):
    global a
    a = get_array(side)
        t = timeit.Timer('%s(a)' % fname,
                     setup='from __main__ import %s, a' % fname)
    return min(t.repeat(reps, 3))  #low num as in place --> converge to 1

# FUNCTIONS
def mac(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])

def mac_two(array_):
    li = range(len(array_[0]))
    for row in range(len(array_)):
        for col in li:
            array_[row][col] = int(round(array_[row][col] * 0.67328))

def mac_three(array_):
    for i, row in enumerate(array_):
        array_[i][:] = [int(round(v * 0.67328)) for v in row]


def senderle(array_):
    array_ = array_.reshape(-1)
    for i, v in enumerate(array_):
        array_[i] = dim(v)

def eryksun(array_):
    array_[:] = vectorize(dim)(array_)

def ufunc_ed(array_):
    multiplied = array_ * 0.67328
    array_[:] = rint(multiplied)

# MAIN
r = []
for fname in ('mac', 'mac_two', 'mac_three', 'senderle', 'eryksun', 'ufunc_ed'):
    print('\nTesting `%s`...' % fname)
    r.append(best(fname, reps=50, side=50))
    # The following is for visually checking the functions returns same results
    tmp = get_array(3)
    eval('%s(tmp)' % fname)
    print tmp
tmp = min(r)/100
print('\n===== ...AND THE WINNER IS... =========================')
print('  mac (as in question)       :  %.4fms [%.0f%%]') % (r[0]*1000,r[0]/tmp)
print('  mac (optimised)            :  %.4fms [%.0f%%]') % (r[1]*1000,r[1]/tmp)
print('  mac (slice-assignment)     :  %.4fms [%.0f%%]') % (r[2]*1000,r[2]/tmp)
print('  senderle                   :  %.4fms [%.0f%%]') % (r[3]*1000,r[3]/tmp)
print('  eryksun                    :  %.4fms [%.0f%%]') % (r[4]*1000,r[4]/tmp)
print('  slice-assignment w/ ufunc  :  %.4fms [%.0f%%]') % (r[5]*1000,r[5]/tmp)
print('=======================================================\n')

The output of the above script - at least in my system - is:

上述脚本的输出(至少在我的系统中)是:

  mac (as in question)       :  88.7411ms [74591%]
  mac (optimised)            :  86.4639ms [72677%]
  mac (slice-assignment)     :  79.8671ms [67132%]
  senderle                   :  85.4590ms [71832%]
  eryksun                    :  13.8662ms [11655%]
  slice-assignment w/ ufunc  :  0.1190ms [100%]

As you can observe, using numpy's ufunc increases speed of more than 2 and almost 3 orders of magnitude compared with the second best and worst alternatives respectively.

正如你所看到的,使用numpy的ufunc可以使速度比第二好的和最差的分别提高2和3个数量级。

If using ufunc is not an option, here's a comparison of the other alternatives only:

如果使用ufunc不是一种选择,这里只是对其他选择的比较:

  mac (as in question)       :  91.5761ms [672%]
  mac (optimised)            :  88.9449ms [653%]
  mac (slice-assignment)     :  80.1032ms [588%]
  senderle                   :  86.3919ms [634%]
  eryksun                    :  13.6259ms [100%]

HTH!

HTH !

#3


3  

Why not using numpy implementation, and the out_ trick ?

为什么不使用numpy实现和out_诀窍呢?

from numpy import array, arange, vectorize, rint, multiply, round as np_round 

def fmilo(array_):
    np_round(multiply(array_ ,0.67328, array_), out=array_)

got:

有:

===== ...AND THE WINNER IS... =========================
  mac (as in question)       :  80.8470ms [130422%]
  mac (optimised)            :  80.2400ms [129443%]
  mac (slice-assignment)     :  75.5181ms [121825%]
  senderle                   :  78.9380ms [127342%]
  eryksun                    :  11.0800ms [17874%]
  slice-assignment w/ ufunc  :  0.0899ms [145%]
  fmilo                      :  0.0620ms [100%]
=======================================================

#4


2  

if ufuncs are not possible, you should maybe consider using cython. it is easy to integrate and give big speedups on specific use of numpy arrays.

如果ufuncs是不可能的,您也许应该考虑使用cython。对numpy数组的特定使用进行集成和加速是很容易的。

#5


0  

This is just an updated version of mac's write-up, actualized for Python 3.x, and with numba and numpy.frompyfunc added.

这只是mac的更新版本,针对Python 3实现。加上numba和numpi .frompyfunc。

numpy.frompyfunc takes an abitrary python function and returns a function, which when cast on a numpy.array, applies the function elementwise.
However, it changes the datatype of the array to object, so it is not in place, and future calculations on this array will be slower.
To avoid this drawback, in the test numpy.ndarray.astype will be called, returning the datatype to int.

As side note:
Numba isn't included in Python's basic libraries and has to be downloaded externally if you want to test it. In this test, it actually does nothing, and if it would have been called with @jit(nopython=True), it would have given an error message saying that it can't optimize anything there. Since, however, numba can often speed-up code written in a functional style, it is included for integrity.

从pyfunc获取一个abitrary python函数并返回一个函数,在向numpy强制转换时返回一个函数。数组,应用函数elementwise。但是,它将数组的数据类型更改为object,因此不存在,对该数组的未来计算将会更慢。为了避免这个缺点,请在test numpi .ndarray中进行测试。将调用astype,将数据类型返回给int.注意:Numba不包括在Python的基本库中,如果您想测试它,必须从外部下载。在这个测试中,它实际上什么都不做,如果用@jit(nopython=True)调用它,它会给出一条错误消息,说它不能在那里优化任何东西。但是,由于numba通常可以加速用函数样式编写的代码,因此它包含在完整性中。

import timeit
from numpy import array, arange, vectorize, rint, frompyfunc
from numba import autojit

# SETUP
get_array = lambda side : arange(side**2).reshape(side, side) * 30
dim = lambda x : int(round(x * 0.67328))

# TIMER
def best(fname, reps, side):
    global a
    a = get_array(side)
    t = timeit.Timer('%s(a)' % fname,
                     setup='from __main__ import %s, a' % fname)
    return min(t.repeat(reps, 3))  #low num as in place --> converge to 1

# FUNCTIONS
def mac(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])

def mac_two(array_):
    li = range(len(array_[0]))
    for row in range(len(array_)):
        for col in li:
            array_[row][col] = int(round(array_[row][col] * 0.67328))

def mac_three(array_):
    for i, row in enumerate(array_):
        array_[i][:] = [int(round(v * 0.67328)) for v in row]


def senderle(array_):
    array_ = array_.reshape(-1)
    for i, v in enumerate(array_):
        array_[i] = dim(v)

def eryksun(array_):
    array_[:] = vectorize(dim)(array_)

@autojit
def numba(array_):
    for row in range(len(array_)):
        for col in range(len(array_[0])):
            array_[row][col] = dim(array_[row][col])


def ufunc_ed(array_):
    multiplied = array_ * 0.67328
    array_[:] = rint(multiplied)

def ufunc_frompyfunc(array_):
    udim = frompyfunc(dim,1,1)
    array_ = udim(array_)
    array_.astype("int")

# MAIN
r = []
totest = ('mac', 'mac_two', 'mac_three', 'senderle', 'eryksun', 'numba','ufunc_ed','ufunc_frompyfunc')
for fname in totest:
    print('\nTesting `%s`...' % fname)
    r.append(best(fname, reps=50, side=50))
    # The following is for visually checking the functions returns same results
    tmp = get_array(3)
    eval('%s(tmp)' % fname)
    print (tmp)
tmp = min(r)/100
results = list(zip(totest,r))
results.sort(key=lambda x: x[1])

print('\n===== ...AND THE WINNER IS... =========================')
for name,time in results:
    Out = '{:<34}: {:8.4f}ms [{:5.0f}%]'.format(name,time*1000,time/tmp)
    print(Out)
print('=======================================================\n')



And finally, the results:

最后,结果:

===== ...AND THE WINNER IS... =========================
ufunc_ed                          :   0.3205ms [  100%]
ufunc_frompyfunc                  :   3.8280ms [ 1194%]
eryksun                           :   3.8989ms [ 1217%]
mac_three                         :  21.4538ms [ 6694%]
senderle                          :  22.6421ms [ 7065%]
mac_two                           :  24.6230ms [ 7683%]
mac                               :  26.1463ms [ 8158%]
numba                             :  27.5041ms [ 8582%]
=======================================================