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Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

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from io import BytesIO

from geometry_msgs.msg import Point

p = Point(x=2, y=4)
print(p)
buff = BytesIO()
p.serialize(buff)
serialized_bytes = buff.getvalue()

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import numpy as np


def largest_indices(array: np.ndarray, n: int) -> tuple:
    """Returns the n largest indices from a numpy array.

    Arguments:
        array {np.ndarray} -- data array
        n {int} -- number of elements to select

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- a 形容词  
	- ad 副形词  
	- ag 形容词性语素  
	- an 名形词  
- b 区别词  
- c 连词  
- d 副词  
	- df   
	- dg 副语素  
- e 叹词  

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Linux 命令行编辑快捷键

初学者在Linux命令窗口（终端）敲命令时，肯定觉得通过输入一串一串的字符的方式来控制计算是效率很低。 但是Linux命令解释器（Shell）是有很多快捷键的，熟练掌握可以极大的提高操作效率。 下面列出最常用的快捷键，这还不是完全版。

• 命令行快捷键：
  • 常用：
    • Ctrl L ：清屏
• Ctrl M ：等效于回车

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import tensorflow as tf

class ImportGraph():
    """  Importing and running isolated TF graph """
    def __init__(self, loc):
        # Create local graph and use it in the session
        self.graph = tf.Graph()
        self.sess = tf.Session(graph=self.graph)
        with self.graph.as_default():
            # Import saved model from location 'loc' into local graph

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import threading

# folk from https://gist.github.com/werediver/4396488
# Based on tornado.ioloop.IOLoop.instance() approach.
# See https://github.com/facebook/tornado
class SingletonMixin(object):
	__singleton_lock = threading.Lock()
	__singleton_instance = None

	@classmethod

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def convex_hull_graham(points):
    '''
    Returns points on convex hull in CCW order according to Graham's scan algorithm. 
    By Tom Switzer <thomas.switzer@gmail.com>.
    '''
    TURN_LEFT, TURN_RIGHT, TURN_NONE = (1, -1, 0)

    def cmp(a, b):
        return (a > b) - (a < b)

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import nltk

text = """The Buddha, the Godhead, resides quite as comfortably in the circuits of a digital
computer or the gears of a cycle transmission as he does at the top of a mountain
or in the petals of a flower. To think otherwise is to demean the Buddha...which is
to demean oneself."""

# Used when tokenizing words
sentence_re = r'''(?x)      # set flag to allow verbose regexps
      ([A-Z])(\.[A-Z])+\.?  # abbreviations, e.g. U.S.A.

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"""Information Retrieval metrics

Useful Resources:
http://www.cs.utexas.edu/~mooney/ir-course/slides/Evaluation.ppt
http://www.nii.ac.jp/TechReports/05-014E.pdf
http://www.stanford.edu/class/cs276/handouts/EvaluationNew-handout-6-per.pdf
http://hal.archives-ouvertes.fr/docs/00/72/67/60/PDF/07-busa-fekete.pdf
Learning to Rank for Information Retrieval (Tie-Yan Liu)
"""
import numpy as np