9.43.2 Greatest hits from previous weeks

9.43.2.1 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 Score of 34

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 Score of 53

9.43.2.2 How do I identify the source of a "Tag times protected" error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11982

I have some code that looks like 
 
 Table[ 
a = 1; 
b = {2, 3} 
c = i;, 
{i, 2} 
] 
 
 
which gives an error: 
Set::write: Tag Times in c {2,3} is Protected.... 
[warning-messages] [syntax] [debugging] [faq]
 

asked by dearN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=204 Score of 31

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 Score of 37

9.43.2.3 Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question 
 
The Mathematica tutorial has a section 'Basic Matrix Operations', describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ... 
[matrix] [list-manipulation] [faq]
 

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 Score of 203

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 Score of 69

9.43.2.4 How to ask Mathematica to imitate Andy Warhol's pop-art painting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59132

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe's portrait so that it looks like Warhol's world famous pop-art painting. However, the result shown below is far from ... 
[image-processing] [generative-art]
 

asked by Putterboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16069 Score of 53

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 Score of 68

9.43.2.5 Why round to even integers?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2116

According to the Mathematica help: 
Round rounds numbers of the form x.5 toward the nearest even integer. 
For example: 
 
 Round[{0.5, 1.5, 2.5, 3.5, 4.5}] 
 
 
gives 
... 
[numerics] [language-design]
 

asked by wxffles https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=427 Score of 88

answered by Per Alexandersson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=488 Score of 54

9.43.2.6 Assign the results from a Solve to variable(s)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=6669

I understand Mathematica can't assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables? 
... 
[equation-solving] [assignment] [faq]
 

asked by stevenvh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1450 Score of 64

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 Score of 38

9.43.2.7 Conversion of Sine to Cosine

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=67521

I'm solving equations with many Cosines and Sines. 
And I want to convert all the Sines to Cosines using trigonometric formulas such as cos(x)=sin(x+pi/2). 
How can I do this? 
[trigonometry] [conversion]
 

asked by YongCheol Kwon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23041 Score of 6

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 Score of 2