================================== Top new questions this week: ==================================
[Why is SatisfiabilityCount faster than SatisfiableQ?] http://mathematica.stackexchange.com/questions/103726/why-is-satisfiabilitycount-faster-than-satisfiableq
Consider the following (large) Boolean expression, which arose in a SAT problem. (The expression is not satisfiable.)
bigExpr = Import["http://pastebin.com/raw/gEgGQ26S"];
On my system (Mathematica ...
- asked by David Zhang (13 votes), answered by Adam Strzebonski (16 votes)
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[ReplaceAll with Associations instead of Rules] http://mathematica.stackexchange.com/questions/103497/replaceall-with-associations-instead-of-rules
I have just noticed that
x /. <|x -> 123|> evaluates to 123
In other words, the association seems to behave as a rule. I didn’t see any example or reference to this behavior in the ...
- asked by Gustavo Delfino (13 votes), answered by Edmund (4 votes)
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[Is it possible to Parallelize Select?] http://mathematica.stackexchange.com/questions/103548/is-it-possible-to-parallelize-select
Given a large list of elements, is it possible to improve Select by parallelizing?
An example: from a 10,000,000-element list of integers between 1 and 10, select all primes
rl = RandomInteger[10, ...
- asked by jjstankowicz (11 votes), answered by bbgodfrey (15 votes)
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[how to enforce a symmetric solution with fem?] http://mathematica.stackexchange.com/questions/103606/how-to-enforce-a-symmetric-solution-with-fem
I’m solving the laplace equation in a domain with holes, and I need to compute the integral of the gradient on the boundary of these holes.
For that I define a mesh and solve the laplace equation ...
- asked by tsuresuregusa (10 votes), answered by user21 (5 votes)
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[Best way to emulate MATLAB’s bsxfun using Map and similar functions] http://mathematica.stackexchange.com/questions/103527/best-way-to-emulate-matlabs-bsxfun-using-map-and-similar-functions
Given a matrix, we want to subtract the mean of each column, from all entries in that column. So given this matrix:
(mat = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) // MatrixForm
the mean ...
- asked by Nasser (10 votes), answered by Mike Honeychurch (11 votes)
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[Order of evaluation - does Mathematica evaluate variables before or after substitution?] http://mathematica.stackexchange.com/questions/103800/order-of-evaluation-does-mathematica-evaluate-variables-before-or-after-substi
Let’s say I write
y = x^2; x = 10; z = y + y^2 + y^3
Does Mathematica internally evaluate y before or after substituting it into z? I.e., does Mathematica internally evaluate this as
y = x^2 = ...
- asked by tparker (9 votes), answered by Alexei Boulbitch (12 votes)
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[How to "inform" successive ContourPlot calculations?] http://mathematica.stackexchange.com/questions/103673/how-to-inform-successive-contourplot-calculations
I need to draw some contour plots of very non-linear functions. As a simple example, take a Mandelbrot Set divergence contour near \(z\approx i\). (Just to be clear, I’m not trying to write a ...
- asked by Jerry Guern (9 votes), answered by bbgodfrey (10 votes)
================================== Greatest hits from previous weeks: ==================================
[How to calculate contour integrals with Mathematica?] http://mathematica.stackexchange.com/questions/34073/how-to-calculate-contour-integrals-with-mathematica
How to calculate the integral of \(\frac {1}{\sqrt {4 z^2 + 4 z + 3}}\) over the unit circle counterclockwise for each branch of the integrand?
- asked by user64494 (20 votes), answered by Artes (39 votes)
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[How do I remove grid from this photo?] http://mathematica.stackexchange.com/questions/88494/how-do-i-remove-grid-from-this-photo
I found this cat a month ago, and I’m not his owners’ friend so the mosquito grid was the inevitable problem. I would like to post-process this photo to get rid of it, but I don’t know exactly how ...
- asked by Nakilon (30 votes), answered by nikie (49 votes)
================================== Can you answer these? ==================================
[Fitting data with unique variable per measurement] http://mathematica.stackexchange.com/questions/103770/fitting-data-with-unique-variable-per-measurement
Imagine we are in the following situation, we have a nonlinear system of functions \(f\) with coordinates \(x_i\), and unknown parameters \(\delta _i\)’s and \(t\). Let this system be defined as,
...
- asked by user19218 (3 votes)
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[‘ParallelTable‘ pending the MathKernel after execution] http://mathematica.stackexchange.com/questions/103611/paralleltable-pending-the-mathkernel-after-execution
I have done a ParallelTable computation in script mode. After execution, the output is fine and I’ve got all the data I needed. but the kernel seems pending, usually it should exit after they finished ...
- asked by buzhidao (2 votes)
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[Call Magma in Mathematica] http://mathematica.stackexchange.com/questions/103602/call-magma-in-mathematica
I’ve written some code in Mathematica, related to some group theory questions I have. Subsequently, I found that part of the code could be significantly sped up if I could just call a routine in ...
- asked by Pace Nielsen (4 votes)