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Analyze audio using Fast Fourier Transform
...you need to calculate the square root of the sum of the square of its real and imaginary components. That is, if your coefficient is a + b*j, then its magnitude is sqrt(a^2 + b^2).
Once you have calculated the magnitude of each FFT coefficient, you need to figure out which audio frequency each FFT ...
In Clojure 1.3, How to read and write a file
I'd like to know the "recommended" way of reading and writing a file in clojure 1.3 .
6 Answers
...
How does the const constructor actually work?
...calized" instance.
That is, all constant expressions begin canonicalized, and later these "canonicalized" symbols are used to recognize equivalence of these constants.
Canonicalization:
A process for converting data that has more than one possible representation into a "standard" canonical repres...
HTML anchor link - href and onclick both?
I want to author an anchor tag that executes some JavaScript and then proceeds to go wherever the href was taking it. Invoking a function that executes my JavaScript and then sets window.location or top.location to the href location doesn't work for me.
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Extract month and year from a zoo::yearmon object
... "%m"))
[1] 3
> as.numeric(format(date1, "%Y"))
[1] 2012
See ?yearmon and ?strftime for details - the latter explains the placeholder characters you can use.
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How can we make xkcd style graphs?
...ly, folk have figured out how to make xkcd style graphs in Mathematica and in LaTeX . Can we do it in R? Ggplot2-ers? A geom_xkcd and/or theme_xkcd?
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How to map a composite key with JPA and Hibernate?
...y the specification also applies. So here they are:
2.1.4 Primary Keys and Entity Identity
...
A composite primary key must
correspond to either a single
persistent field or property or to a
set of such fields or properties as
described below. A primary key class
must be defi...
Is < faster than
...n two machine instructions:
A test or cmp instruction, which sets EFLAGS
And a Jcc (jump) instruction, depending on the comparison type (and code layout):
jne - Jump if not equal --> ZF = 0
jz - Jump if zero (equal) --> ZF = 1
jg - Jump if greater --> ZF = 0 and SF = OF
(etc...)
Exa...
AJAX POST and Plus Sign ( + ) — How to Encode?
I'm POSTing the contents of a form field via AJAX to a PHP script and using JavaScript to escape(field_contents) . The problem is that any plus signs are being stripped out and replaced by spaces. How can I safely 'encode' the plus sign and then appropriately 'decode' it on the PHP side?
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Force R not to use exponential notation (e.g. e+10)?
...a grey area. You need to recall that R will always invoke a print method, and these print methods listen to some options. Including 'scipen' -- a penalty for scientific display. From help(options):
‘scipen’: integer. A penalty to be applied when deciding to print
numeric value...