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What is the fastest way to get the value of π?

... fastest π I know of is the one with the digits hard coded. Looking at Pi and Pi[PDF], there are a lot of formulae. Here is a method that converges quickly — about 14 digits per iteration. PiFast, the current fastest application, uses this formula with the FFT. I'll just write the formula, since...
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Why does the C preprocessor interpret the word “linux” as the constant “1”?

... In the Old Days (pre-ANSI), predefining symbols such as unix and vax was a way to allow code to detect at compile time what system it was being compiled for. There was no official language standard back then (beyond the reference material at the back of the first edition of K&R), a...
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find vs find_by vs where

...is used as a helper when you're searching for information within a column, and it maps to such with naming conventions. For instance, if you have a column named name in your database, you'd use the following syntax: Model.find_by(name: "Bob") .where is more of a catch all that lets you use a bit...
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Array Size (Length) in C#

...nt[,] b = new int[3, 5];) b.Rank will give the number of dimensions (2) and b.GetLength(dimensionIndex) will get the length of any given dimension (0-based indexing for the dimensions - so b.GetLength(0) is 3 and b.GetLength(1) is 5). See System.Array documentation for more info. As @Lucero ...
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How can I export tables to Excel from a webpage [closed]

...s to Excel from a webpage. I want the export to contain all the formatting and colours. 14 Answers ...
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fatal: early EOF fatal: index-pack failed

I have googled and found many solutions but none work for me. 31 Answers 31 ...
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Context switches much slower in new linux kernels

...e intel_idle driver ignores the user's BIOS configuration for the C-states and dances to its own tune. In other words, even if you completely disable all C states in your PC's (or server's) BIOS, this driver will still force them on during periods of brief inactivity, which are almost always happeni...
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One Activity and all other Fragments [closed]

I am thinking of implementing one screen with Activity and all other sreens with Fragments and managing all the fragments thru the activity . ...
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What is the difference between linear regression and logistic regression?

...ut as probabilities but it's a mistake because the output can be negative, and greater than 1 whereas probability can not. As regression might actually produce probabilities that could be less than 0, or even bigger than 1, logistic regression was introduced. Source: http://gerardnico.com/wiki/dat...
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How many GCC optimization levels are there?

...e even more) -Ofast (optimize very aggressively to the point of breaking standard compliance) -Og (Optimize debugging experience. -Og enables optimizations that do not interfere with debugging. It should be the optimization level of choice for the standard edit-compile-debug cycle, offeri...