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Why is there huge performance hit in 2048x2048 versus 2047x2047 array multiplication?

...L is always power of 2. The six comes from fact that 2^6 == 64 bytes is standard size of cache line. Now what does this mean? Well it means that if I have address X and address Y and (X >> 6) - (Y >> 6) is divisible by L (i.e. some large power of 2), they will be stored in the same ca...
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How do I prevent Android taking a screenshot when my app goes to the background?

...R.layout.main); } } This definitely secures against manual screenshots and automatic screenshots from the ICS recent-tasks history. It also secures against screen recording (e.g., apps using the media projection APIs). UPDATE: it also secures against Now On Tap or other assistants on Android 6....
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Why are dates calculated from January 1st, 1970?

Is there any reason behind using date(January 1st, 1970) as default standard for time manipulation? I have seen this standard in Java as well as in Python. These two languages I am aware of. Are there other popular languages which follows the same standard? ...
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Why is lazy evaluation useful?

... You can actually emulate an infinite list in Python using generators and generator expressions (which work in a similar way to a list comprehension): python.org/doc/2.5.2/ref/genexpr.html – John Montgomery Nov 5 '08 at 15:11 ...
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how to change default python version?

... in my mac. After I run /Applications/Python 3.2/Update Shell Profile.command , it's confusing that when I type python -V in Terminal it says that Python 2.6.1 , how can I change the default python version? ...
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Cost of len() function

...ength of the element - very fast) on every type you've mentioned, plus set and others such as array.array. share | improve this answer | follow | ...
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Move all files except one

... If you use bash and have the extglob shell option set (which is usually the case): mv ~/Linux/Old/!(Tux.png) ~/Linux/New/ share | improve...
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Returning an array using C

I am relatively new to C and I need some help with methods dealing with arrays. Coming from Java programming, I am used to being able to say int [] method() in order to return an array. However, I have found out that with C you have to use pointers for arrays when you return them. Being a new progr...
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Difference between del, remove and pop on lists

...;>> a = [9, 8, 7, 6] >>> del a[1] >>> a [9, 7, 6] and pop removes the item at a specific index and returns it. >>> a = [4, 3, 5] >>> a.pop(1) 3 >>> a [4, 5] Their error modes are different too: >>> a = [4, 5, 6] >>> a.remove(7) T...
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How to cast Object to its actual type?

...e(obj, null); // interface IFoo foo = (IFoo)obj; // where SomeType : IFoo and IFoo declares MyFunction foo.MyFunction(); // dynamic dynamic d = obj; d.MyFunction(); share | improve this answer ...