NLTK表现

Question

好吧,我最近对自然语言处理非常感兴趣:但是,在我的大部分工作中,我一直使用C语言.我听说过NLTK,我不懂Python,但它似乎很容易学习,它看起来像一个非常强大和有趣的语言.特别是,NLTK模块似乎非常适合我需要做的事情.

但是,当使用NLTK的示例代码并将其粘贴到一个名为的文件中时test.py,我注意到它需要非常长的时间才能运行!

我是这样从shell调用的:

time python ./test.py

在具有4 GB RAM的2.4 GHz机器上,需要19.187秒!

现在,也许这是绝对正常的,但我的印象是NTLK 非常快; 我可能错了,但是有什么明显的东西我在这里显然做错了吗？

Answer 1

我相信你将培训时间与处理时间混为一谈.像UnigramTagger一样训练模型可能会花费很多时间.因此可以从磁盘上的pickle文件加载训练有素的模型.但是一旦你将模型加载到内存中,处理就会非常快.请参阅我的帖子底部的"分类器效率" 部分,使用NLTK进行部分语音标记,以了解不同标记算法的处理速度.

Answer 2

@Jacob是关于将训练和标记时间混为一谈的.我已经简化了示例代码,这里是时间细分:

Importing nltk takes 0.33 secs
Training time: 11.54 secs
Tagging time: 0.0 secs
Sorting time: 0.0 secs

Total time: 11.88 secs

系统:

CPU: Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz
Memory: 3.7GB

码:

import pprint, time
startstart = time.clock()

start = time.clock()
import nltk
print "Importing nltk takes", str((time.clock()-start)),"secs"

start = time.clock()
tokenizer = nltk.tokenize.RegexpTokenizer(r'\w+|[^\w\s]+')
tagger = nltk.UnigramTagger(nltk.corpus.brown.tagged_sents())
print "Training time:",str((time.clock()-start)),"secs"


text = """Mr Blobby is a fictional character who featured on Noel
Edmonds' Saturday night entertainment show Noel's House Party,
which was often a ratings winner in the 1990s. Mr Blobby also
appeared on the Jamie Rose show of 1997. He was designed as an
outrageously over the top parody of a one-dimensional, mute novelty
character, which ironically made him distinctive, absurd and popular.
He was a large pink humanoid, covered with yellow spots, sporting a
permanent toothy grin and jiggling eyes. He communicated by saying
the word "blobby" in an electronically-altered voice, expressing
his moods through tone of voice and repetition.

There was a Mrs. Blobby, seen briefly in the video, and sold as a
doll.

However Mr Blobby actually started out as part of the 'Gotcha'
feature during the show's second series (originally called 'Gotcha
Oscars' until the threat of legal action from the Academy of Motion
Picture Arts and Sciences[citation needed]), in which celebrities
were caught out in a Candid Camera style prank. Celebrities such as
dancer Wayne Sleep and rugby union player Will Carling would be
enticed to take part in a fictitious children's programme based around
their profession. Mr Blobby would clumsily take part in the activity,
knocking over the set, causing mayhem and saying "blobby blobby
blobby", until finally when the prank was revealed, the Blobby
costume would be opened - revealing Noel inside. This was all the more
surprising for the "victim" as during rehearsals Blobby would be
played by an actor wearing only the arms and legs of the costume and
speaking in a normal manner.[citation needed]"""

start = time.clock()
tokenized = tokenizer.tokenize(text)
tagged = tagger.tag(tokenized)
print "Tagging time:",str((time.clock()-start)),"secs"

start = time.clock()
tagged.sort(lambda x,y:cmp(x[1],y[1]))
print "Sorting time:",str((time.clock()-start)),"secs"

#l = list(set(tagged))
#pprint.pprint(l)
print
print "Total time:",str((time.clock()-startstart)),"secs"