3.2 Tuesday, January 9, 2018

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Top new questions this week: 
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[Why is Unevaluated[#]& different from Unevaluated?] https://mathematica.stackexchange.com/questions/163291/why-is-unevaluated-different-from-unevaluated

{a, b, c} = {1, 2, 3}; 
Unevaluated /@ Unevaluated@{a, b, c} 
(* {Unevaluated[a], Unevaluated[b], Unevaluated[c]} *) 
Unevaluated[#]& /@ Unevaluated@{a, b, c} 
(* {Unevaluated[1], Unevaluated[2],  ...

- asked by Roman (18 votes), answered by Szabolcs (19 votes)

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[Building a GitBook with Mathematica] https://mathematica.stackexchange.com/questions/163193/building-a-gitbook-with-mathematica

GitBook is a fun little website that will take Markdown source material and build a little book out of it.

How can I use Mathematica to build a GitBook with a minimum of effort?

- asked by b3m2a1 (14 votes), answered by b3m2a1 (18 votes)

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[How to create a vertical bullet gauge?] https://mathematica.stackexchange.com/questions/163201/how-to-create-a-vertical-bullet-gauge

Originally posted in MathematicaMeta SE, titled "I can’t understand why Mathematica has an excellent (perhaps the best!) BulletGauge command (with multiple options)", as a reflexion about the ...

- asked by Mika Ike (10 votes), answered by kglr (14 votes)

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[Specialized form of Outer[f, list, list] for symmetric f] https://mathematica.stackexchange.com/questions/163240/specialized-form-of-outerf-list-list-for-symmetric-f

Consider a function f that is symmetric with regard to its two arguments i.e. f[x,y] == f[y,x]. Using Outer one can for instance build a correspondence matrix that computes some distance measure f ...

- asked by Sascha (9 votes), answered by Henrik Schumacher (5 votes)

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[How to convert a string having nested parentheses into an expression?] https://mathematica.stackexchange.com/questions/163184/how-to-convert-a-string-having-nested-parentheses-into-an-expression

I am a Wolfram Language/Mathematica beginner and trying to convert STEP ISO10303 commands into geometrical regions. A simple command looks like

(vector(a,(b,c)),line(d,(e,f))

I tried with String ...

- asked by Markus Sonderegger (9 votes), answered by John Doty (9 votes)

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[Is there any way to speed up this code that’s Maximizing a function got from numerical integration?] https://mathematica.stackexchange.com/questions/163204/is-there-any-way-to-speed-up-this-code-thats-maximizing-a-function-got-from-num

I have this code below, which is calculating the Binding energy of an electron in a Quantum Well Wire with a hydrogenic impurity in it. Well you don’t have to care much about what kind of calculation ...

- asked by tyler_house (7 votes), answered by Michael E2 (7 votes)

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[Joining all the keys of a list of rules that point to matching values] https://mathematica.stackexchange.com/questions/163068/joining-all-the-keys-of-a-list-of-rules-that-point-to-matching-values

Suppose I have a list of rules whose keys are not of identical structure (in my case, the keys are either lists of at least one symbol or symbols alone):

rules = {{a} -> 1, {b, c} -> 1, d ->  ...

- asked by user170231 (7 votes), answered by Kuba (10 votes)

================================== Greatest hits from previous weeks: ==================================

[How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?] https://mathematica.stackexchange.com/questions/8895/how-to-calculate-scalar-curvature-ricci-tensor-and-christoffel-symbols-in-mathem

I am seeking a convenient and effective way to calculate such geometric quantities. I’ve used packages like TensoriaCalc, but they don’t work at all time. Sometimes, I run into the following error: ...

- asked by Zoe Rowa (29 votes), answered by Yi-Zen Chu (12 votes)

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[xkcd-style Plots] https://mathematica.stackexchange.com/questions/11350/xkcd-style-plots

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn’t manage it. Everything I drew looked perfect, and I don’t have enough command over PlotLegends to have these ...

- asked by Amatya (554 votes), answered by Simon Woods (409 votes)

================================== Can you answer these? ==================================

[Is ClearAttributes built-in functon work in current cell only?] https://mathematica.stackexchange.com/questions/163223/is-clearattributes-built-in-functon-work-in-current-cell-only

I have a question. Is ClearAttributes the built-in functon work in current cell only? This is my code:

In first cell: 
 
Set[a, 6] 
 
 
In second cell: 
 
ClearAttributes[Set, HoldFirst] 
Attributes[Set] 
 ...

- asked by SIJA (1 vote)

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[How to convert Piecewise into KroneckerDelta form by FullSimplify?] https://mathematica.stackexchange.com/questions/163274/how-to-convert-piecewise-into-kroneckerdelta-form-by-fullsimplify

The question comes from the last example of this topic in the Wolfram documentation.

SeriesCoefficient[E^x^2, {x, 0, n}] 
 
However, my (v11.1) output is 
 
$\begin{cases} 
\frac1{{\sf  ...

- asked by ooo (1 vote)

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[Code behind these Video Playback demos?] https://mathematica.stackexchange.com/questions/163008/code-behind-these-video-playback-demos

There are only two known examples of video playback (from a file) within a (non-cloud) notebook:

Visualizations in Graph Theory with the Wolfram Language (at time 3:32) Mathematica and CUDA, ...

- asked by user5601 (3 votes)