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Why does Double.NaN==Double.NaN return false?
...cluding NaN. This is part of the IEEE 754 standard and implemented by the CPU/FPU. It is not something the JVM has to add any logic to support.
http://en.wikipedia.org/wiki/NaN
A comparison with a NaN always returns an unordered result even when comparing with itself. ... The equality and ine...
Combine two columns of text in pandas dataframe
...[252]: (200000, 2)
UPDATE: new timings using Pandas 0.19.0
Timing without CPU/GPU optimization (sorted from fastest to slowest):
In [107]: %timeit df['Year'].astype(str) + df['quarter']
10 loops, best of 3: 131 ms per loop
In [106]: %timeit df['Year'].map(str) + df['quarter']
10 loops, best of 3: ...
node.js child process - difference between spawn & fork
...o node processes per core, perhaps more for machines with a good ram clock/cpu clock ratio, or for node processes heavy on I/O and light on CPU work, to minimize the down time the event loop is waiting for new events. However, the latter suggestion is a micro-optimization, and would need careful be...
那些年 O2O创业我踩了十个坑 - 资讯 - 清泛网 - 专注C/C++及内核技术
...此一来，公司团队看似整齐而豪华，但内部却出现了很多问题，由于大家背景各异，来自于国企、外企和民企，处事风格完全迥异，很多事情在讨论中反复，反复后再讨论，浪费了大量的时间在开会和制定战略中，而且大家的价...
Is “IF” expensive?
...truction reordering, at the compiler level, and also to some extent on the CPU level (for an out-of-order CPU, of course). Nice detailed answer though.
– jalf
Nov 24 '08 at 20:58
5...
通过FastCGI Cache实现服务降级 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...没有合理的降级方案，那么结局必然是死路一条。
任何问题一旦脱离了实际情况，便失去了讨论的意义。在继续之前，不妨先介绍一下案例的背景情况：一个PHP网站，以读为主，原本躲在CDN后面，运行很稳定，后来新增了很多...
大数据时代的数据化运营 - 资讯 - 清泛网 - 专注C/C++及内核技术
...下，我们在运营中看到可以获得有效数据的原始数据不是问题，去除无效和虚假的数据才是关键。
相信做发行的同行都知道，在实践中，会遇到通过某些渠道或者是CPS，或者是广告渠道，他们一定会有大量的虚假的数据在里面...
Go > operators
...me extra work when the shift count is a number.
Shift instructions in x86 CPUs consider only 5 bits (6 bits on 64-bit x86 CPUs) of the shift count. In languages like C/C++, the shift operator translates into a single CPU instruction.
The following Go code
x := 10
y := uint(1025) // A big shift c...
How is the fork/join framework better than a thread pool?
...f thread pools and Fork/Join are alike: Both want to utilize the available CPU power the best they can for maximum throughput. Maximum throughput means that as many tasks as possible should be completed in a long period of time. What is needed to do that? (For the following we will assume that there...
Deep Learning（深度学习）学习笔记整理系列之（二） - 大数据 & AI - 清泛...
...试图同时用生理学和计算机的手段，双管齐下，研究视觉问题。
他们收集了很多黑白风景照片，从这些照片中，提取出400个小碎片，每个照片碎片的尺寸均为 16x16 像素，不妨把这400个碎片标记为 S[i], i = 0,.. 399。接下来，...