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How is this fibonacci-function memoized?
...mechanism in Haskell is by-need: when a value is needed, it is calculated, and kept ready in case it is asked for again. If we define some list, xs=[0..] and later ask for its 100th element, xs!!99, the 100th slot in the list gets "fleshed out", holding the number 99 now, ready for next access.
Th...
Convert PDF to image with high resolution
I'm trying to use the command line program convert to take a PDF into an image (JPEG or PNG). Here is one of the PDFs that I'm trying to convert.
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MySQL Server has gone away when importing large sql file
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As stated here:
Two most common reasons (and fixes) for the MySQL server has gone away
(error 2006) are:
Server timed out and closed the connection. How to fix:
check that wait_timeout variable in your mysqld’s my.cnf configuration file is large en...
Checking for a dirty index or untracked files with Git
...;/dev/null| grep "^M" | wc -l)
# Get number of files that are uncommitted and not added
expr $(git status --porcelain 2>/dev/null| grep "^ M" | wc -l)
# Get number of total uncommited files
expr $(git status --porcelain 2>/dev/null| egrep "^(M| M)" | wc -l)
Note: The 2>/dev/null filters...
Does assignment with a comma work?
Why does aaa = 1,2,3 work and set the value of aaa to 1 ?
4 Answers
4
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Are 2^n and n*2^n in the same time complexity?
... answer this question.
The definition is that f(x) belongs to O(g(x)) if and only if the limit limsupx → ∞ (f(x)/g(x)) exists i.e. is not infinity. In short this means that there exists a constant M, such that value of f(x)/g(x) is never greater than M.
In the case of your question let f(n) ...
Collection versus List what should you use on your interfaces?
... the question as to why not List<T>, The reasons are future-proofing and API simplicity.
Future-proofing
List<T> is not designed to be easily extensible by subclassing it; it is designed to be fast for internal implementations. You'll notice the methods on it are not virtual and so can...
Is there a UIView resize event?
I have a view that has rows and columns of imageviews in it.
7 Answers
7
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FFMPEG (libx264) “height not divisible by 2”
...not want to scale the video is:
-vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"
Command:
ffmpeg -r 24 -i frame_%05d.jpg -vcodec libx264 -y -an video.mp4 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"
Basically, .h264 needs even dimensions so this filter will:
Divide the original height and width by 2
Round it up t...
Should I use multiplication or division?
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Thanks for the tip on using the time command for benchmarking!
– Edmundito
Oct 22 '08 at 17:11
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