7.40 March 11, 2014
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Top new questions this week:
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[Most influential and/or disrupting features introduced with new
versions of
Mathematica]\url{http://mathematica.stackexchange.com/questions/43631/most-
influential-and-or-disrupting-features-introduced-with-new-versions-of-m
ath}
This is something that has been bugging me for ages.
With every upgrade, Mathematica has added new functionalities and
amendend some of its bugs. In the process, though, some older
functionality has ...
- asked by Peltio (11 votes), answered by Mark Adler (3 votes)
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[Fast way to get positions of "boxed" array
elements?]\url{http://mathematica.stackexchange.com/questions/43557/fast-wa
y-to-get-positions-of-boxed-array-elements}
Given a 2D array (arbitrary numeric / evaluates to numeric elements,
simplified for examples, and can be arbitrary dimensions so long as the
operation makes sense, I'm working with 2K X 2K in my ...
- asked by rasher (9 votes), answered by rasher (6 votes)
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[Drop selection of columns from a ragged
array]\url{http://mathematica.stackexchange.com/questions/43785/drop-select
ion-of-columns-from-a-ragged-array}
I have an application where I need to drop some arbitrary list of
columns from a ragged array (where of course the shortest array rows
have at least all the specified columns).
E.g., given a ragged ...
- asked by rasher (8 votes), answered by Mr.Wizard (6 votes)
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[How to match a cyclically repeating
sequence?]\url{http://mathematica.stackexchange.com/questions/43801/how-to-
match-a-cyclically-repeating-sequence}
I have run across several times recently where I must match a sequence
that is cyclically repeating. For example, with the sequence,
Sequence[a, b, c]
how would I write a pattern that matched ...
- asked by rcollyer (7 votes), answered by rm -rf (3 votes)
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[Is there a function which instantly tells you whether an element is
part of a
list?]\url{http://mathematica.stackexchange.com/questions/43541/is-there-a-
function-which-instantly-tells-you-whether-an-element-is-part-of-a-li}
I have a very long list of numbers and I want to check whether there's a
function (something that would look like PartOfQ[element,list]) that
tells you immediately with a True or False as to whether ...
- asked by Aron (7 votes), answered by Szabolcs (7 votes)
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[Suppress connection to Wolfram|Alpha when making unit
conversions]\url{http://mathematica.stackexchange.com/questions/43515/suppr
ess-connection-to-wolframalpha-when-making-unit-conversions}
I want to speed up calculations with unit conversions. I suspect
primarily that some units evaluate from Wolfram|Alpha. Any way to
prevent this automatically, so that Mathematica throws ...
- asked by denfromufa (7 votes), answered by rm -rf (5 votes)
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[How to handle keyboard events for unselected item in
CDF?]\url{http://mathematica.stackexchange.com/questions/43432/how-to-handl
e-keyboard-events-for-unselected-item-in-cdf}
How can I force the keyboard input to work for this cell without
clicking on it after I evaluate or showing a blinking selection cursor?
This is for running CDF games in a browser.
pos = {0, 0};
...
- asked by Michael Hale (6 votes), answered by Michael Hale (3 votes)
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Greatest hits from previous weeks:
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[3D heatmap density
plot]\url{http://mathematica.stackexchange.com/questions/17260/3d-heatmap-d
ensity-plot}
I have a set of data that looks like {{x1, y1, z1}, {x2, y2, z2}, ...}
so it describes points in 3D space. I want to make a heatmap out of this
data. So that points with a high density are shown as a ...
- asked by norty (25 votes), answered by PlatoManiac (27 votes)
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[Plotting the frequency spectrum of a data series using
Fourier]\url{http://mathematica.stackexchange.com/questions/18082/plotting-
the-frequency-spectrum-of-a-data-series-using-fourier}
testData = Table[N@Sin[500 x], {x, 0, 100}];
ListLinePlot[Abs[Fourier[testData]], PlotRange -> Full]
Gives me
Which I do not expect because the Fourier Transform is
FourierTransform[Sin[500 ...
- asked by Pickett (7 votes), answered by KennyColnago (8 votes)
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Can you answer these?
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[Fourier transformation of HeavisideTheta
functions]\url{http://mathematica.stackexchange.com/questions/43445/fourier
-transformation-of-heavisidetheta-functions}
I want to find 2D-Fourier transformation of the function given below
f = HeavisideTheta[y1]*HeavisideTheta[y2 - y1]
For the purpose, I use built-in function in two ways as below,
...
- asked by user58226 (3 votes)
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[Autocomplete from inside Module and
SetDelayed]\url{http://mathematica.stackexchange.com/questions/43393/autoco
mplete-from-inside-module-and-setdelayed}
Autocomplete in Mathematica 9 offers suggestions from inside SetDelayed
and Module. For example, after running:
func[thing1_, thing2_] := thing1 + thing2;
Module[{thing3},
thing3 = 10;
thing3 + 4
]
...
- asked by Italianice (1 vote)
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[Slow mixture fitting when having ill-conditioned covariance matrices.
How to make it
faster?]\url{http://mathematica.stackexchange.com/questions/43592/slow-mixt
ure-fitting-when-having-ill-conditioned-covariance-matrices-how-to-mak}
I'm using Mathematica 9.0 to fit multidimensional observations with a
gaussian mixture. To do so I first adapted these steps to ensure that
the mixture parameters are well defined (see ...
- asked by p-d (1 vote)