7.22 August 5, 2014
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Top new questions this week:
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[Numerically solving Helmholtz equation in 2D for arbitrary
shapes]\url{http://mathematica.stackexchange.com/questions/56305/numericall
y-solving-helmholtz-equation-in-2d-for-arbitrary-shapes}
I would like to solve the Helmholtz equation with dirichlet boundary
conditions in 2 dimensions for an arbitrary shape. (for a qualitative
comparison of the eigenstates to periodic orbits in the ...
- asked by Julian S. (25 votes), answered by Mark McClure (20 votes)
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[V10's Operator Forms - what are they good
for?]\url{http://mathematica.stackexchange.com/questions/56504/v10s-operato
r-forms-what-are-they-good-for}
V10 introduces an operator form for several functions perhaps primarily
due to their role in queries as part of introducing data science
functionality. At first pass it seems a lot of effort to add ...
- asked by Ronald Monson (22 votes), answered by Simon Woods (24 votes)
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[Why is Query so much slower than
Part?]\url{http://mathematica.stackexchange.com/questions/56609/why-is-quer
y-so-much-slower-than-part}
Time for another of these(1),(2) as yet another new-in-10 function
appears to have poor performance compared to older alternatives. This
time: Query appears to be orders of magnitude slower than Part ...
- asked by Mr.Wizard (15 votes), answered by m_goldberg (8 votes)
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[BitShiftRight produces incorrect results in Version
10]\url{http://mathematica.stackexchange.com/questions/56241/bitshiftright-
produces-incorrect-results-in-version-10}
With Mathematica 10 for Mac, BitShiftRight works properly on lists of up
to 100000 numbers, but appears to give incorrect results when threaded
over lists of 100001 or more:
v1 = Table[i, {i, 1, ...
- asked by DBM (14 votes), answered by Mr.Wizard (9 votes)
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[Speed of curated data calls in Version
10]\url{http://mathematica.stackexchange.com/questions/56172/speed-of-curat
ed-data-calls-in-version-10}
Curated datasets underwent a significant overhaul in version 10,
primarily in the way content is delivered in the form of Objects and
Entities. Additionally, it appears that this change in content ...
- asked by bobthechemist (14 votes), answered by Nick Lariviere (13
votes)
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[the winding number for the circle map (Arnold
tongue)]\url{http://mathematica.stackexchange.com/questions/56499/the-windi
ng-number-for-the-circle-map-arnold-tongue}
I want to do an iterative calculation:
f[n_, a_, b_] := Nest[# + a - b Sin[2 Pi #] &, 0, n]/n;
If I use i use the machine precision, it maybe produce a great error,for
example:
N@f[500, 1/2, ...
- asked by Chenminqi (12 votes), answered by heropup (10 votes)
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[Speed up adding Poisson noise to an
image]\url{http://mathematica.stackexchange.com/questions/56180/speed-up-ad
ding-poisson-noise-to-an-image}
I'm simulating some images corrupted with Poisson noise, but I'm
encountering a few problems with performance. According to the
documentation on ImageEffect, one can add Poisson noise according to the
...
- asked by blochwave (11 votes), answered by blochwave (16 votes)
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Greatest hits from previous weeks:
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[How can I add drop shadows and specular highlights to 2D
graphics?]\url{http://mathematica.stackexchange.com/questions/43186/how-can
-i-add-drop-shadows-and-specular-highlights-to-2d-graphics}
I thought I'd share some code in the form of a self-answered question,
but other answers are of course welcome.
Drop shadows are a familiar visual effect, giving the impression of a
graphical element ...
- asked by Simon Woods (31 votes), answered by Simon Woods (35 votes)
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[Resources for beautiful Mathematica
Stylesheets]\url{http://mathematica.stackexchange.com/questions/5846/resour
ces-for-beautiful-mathematica-stylesheets}
When the Wolfram Demonstrations were introduced and the
Documentation-Center was redesigned, I remember it was the first time I
thought someone had put some effort into creating a beautiful ...
- asked by halirutan (81 votes), answered by rm -rf (41 votes)
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Can you answer these?
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[DatabaseLink Example for DB2 and
Mathematica]\url{http://mathematica.stackexchange.com/questions/56283/datab
aselink-example-for-db2-and-mathematica}
could someone please point me to good example on how to make a JDBC
connection to an IBM DB2 database?
- asked by Rick QI (1 vote)
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[Precision problem while evaluating RegionMember or Element in
V10]\url{http://mathematica.stackexchange.com/questions/56402/precision-pro
blem-while-evaluating-regionmember-or-element-in-v10}
I'll try to give you a background on where the problem occured. The
problem itself is defined near the end of the post.
I'm running a sort of a simulation of a particle in a box. I finally got
my ...
- asked by Daroslav (3 votes)
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[Workarounds for a possible bug in the linearity of
FourierTransform]\url{http://mathematica.stackexchange.com/questions/56237/
workarounds-for-a-possible-bug-in-the-linearity-of-fouriertransform}
This is somewhat similar to this question, except the problem I am
encountering is to do with Fourier transforms of scalar multiples of
functions and their derivatives.
I wish to input ...
- asked by Oliver Lunt (2 votes)