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Approximate cost to access various caches and main memory?

...xample, check page 22 for some timings & cycles for example). Additionally, this page has some details on clock cycles etc. The second link served the following numbers: Core i7 Xeon 5500 Series Data Source Latency (approximate) [Pg. 22] local L1 CACHE hit, ...
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Difference between a theta join, equijoin and natural join

... A theta join allows for arbitrary comparison relationships (such as ≥). An equijoin is a theta join using the equality operator. A natural join is an equijoin on attributes that have the same name in each relationship. Additionally,...
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Does C have a “foreach” loop construct?

Almost all languages have a foreach loop or something similar. Does C have one? Can you post some example code? 12 Answer...
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Count how many files in directory PHP

...n you include other directories within that directories and so on to count all files and exclude directories from the count? – The Bumpaster Jul 2 '16 at 13:40 1 ...
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What is the difference between shallow copy, deepcopy and normal assignment operation?

...ble towards the existing object. The docs explain the difference between shallow and deep copies: The difference between shallow and deep copying is only relevant for compound objects (objects that contain other objects, like lists or class instances): A shallow copy constructs a new...
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Reference: What is variable scope, which variables are accessible from where and what are “undefined

... be in the global scope in a.php doesn't necessarily mean they are, it actually depends on which context that code is included/executed in. What about functions inside functions and classes? Every new function declaration introduces a new scope, it's that simple. (anonymous) functions inside func...
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libpthread.so.0: error adding symbols: DSO missing from command line

...nd line after the object files being compiled: gcc -Wstrict-prototypes -Wall -Wno-sign-compare -Wpointer-arith -Wdeclaration-after-statement -Wformat-security -Wswitch-enum -Wunused-parameter -Wstrict-aliasing -Wbad-function-cast -Wcast-align -Wstrict-prototypes -Wold-style-definition -Wmissing-pr...
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关于 __VA_ARGS__ 宽字符版本的问题 - C/C++ - 清泛网 - 专注C/C++及内核技术

关于 __VA_ARGS__ 宽字符版本的问题在写一个可变参数的记录日志函数,考虑到宽字符(Unicode版本)时:#define WIDEN2(x) L ## x#define WIDEN(x) WIDEN2(x)#define __...在写一个可变参数的记录日志函数,考虑到宽字符(Unicode版本)时: #defin...
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How does C compute sin() and other math functions?

...on in C, contributed by IBM. Since October 2011, this is the code that actually runs when you call sin() on a typical x86-64 Linux system. It is apparently faster than the fsin assembly instruction. Source code: sysdeps/ieee754/dbl-64/s_sin.c, look for __sin (double x). This code is very complex. N...
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Difference between reduce and foldLeft/fold in functional programming (particularly Scala and Scala

...t is both commutative and associative. This means the operation can be parallelized. This distinction is very important for Big Data / MPP / distributed computing, and the entire reason why reduce even exists. The collection can be chopped up and the reduce can operate on each chunk, then the red...