6.21.2 Greatest hits from previous weeks

6.21.2.1 Plot, extract data to a file

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19859

I need to save data that Mathematica uses inside the  Plot  command. The format that I would like to have is: 
 
 x1 y1 
x2 y2 
..... 
 
 
... 
[plotting] [export]
 

asked by molkee https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5097 30 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 47 votes

6.21.2.2 How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8895

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,... 
[tensors] [differential-geometry]
 

asked by Zoe Rowa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1713 38 votes

answered by Yi-Zen Chu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4869 18 votes

6.21.2.3 How can I improve Mathematica's resolution on a macbook retina display?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18419

Mathematica 9.0 looks a bit fuzzy on the retina screen, how can I increase the resolution? 
Here another screenshot showing a direct comparison between the browser and Mathematica 
[front-end] [version-9] [mac-os-x]
 

asked by Tom Wellington https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2437 44 votes

6.21.2.4 Code that generates a mandala

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=136974

My little brother asked me to print original mandalas for coloring. I would like some idea on how to create them, but without color, so he can color them. 
 
examples 
[graphics] [programming] [generative-art]
 

asked by zeros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26849 71 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 95 votes

6.21.2.5 How to create effect like Van Gogh's stroke brush?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39003

I need to apply Van Gogh's stroke brush effect to a random image 
Take the following image as an example: 
 
Thank you so much if you could help! 
[image-processing] [code-request] [generative-art]
 

asked by user10495 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10495 34 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 51 votes

6.21.2.6 Find eigen energies of time-independent Schrödinger equation

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32293

I'm trying to get the eigenvalues of a one dimensional time-independent Schrödinger equation, 
 
$-\frac{h^2}{2m_0}\frac{d^2\psi}{dx^2}+U(x)~\psi=Ei~\psi$ 
 
where U(x) is some potential and Ei is the ... 
[equation-solving] [physics] [parametric-functions]
 

asked by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 48 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 46 votes

6.21.2.7 How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list  x={2,4,6,8,10}  and I want to find out the positions of the elements that are greater than 7. 
 
... 
[list-manipulation]
 

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 66 votes

answered by J. M.'s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 63 votes