6.15.2 Greatest hits from previous weeks

6.15.2.1 Is there an open source implementation of Mathematica-the-language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4454

I've seen questions before such as "What is the best open-source equivalent for Mathematica?", but that specific question (and that line of inquiry in general) cares more about the computer algebra  ... 
[programming] [open-source]
 

asked by sblom https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=178 121 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

6.15.2.2 Image processing: Floor plan - detecting rooms' borders (area) and room names' texts

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19546

 
 
Here is a simple building floor plan. I would like to derive the rooms as (rectangular) components and the names of the rooms. This is very common representation of building floor plans. 
 
The  ... 
[image-processing]
 

asked by s.s.o https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=840 63 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 58 votes

6.15.2.3 How to make Jacobian automatically in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=5790

If we have two vectors, $a$ and $b$, how can I make Jacobian matrix automatically in Mathematica? 
 
$$ a=\left( 
\begin{array}{c} 
x_1^3+2x_2^2 \\ 
3x_1^4+7x_2 
\end{array} 
\right);b=\left( 
... 
[vector-calculus]
 

asked by George Mills https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1012 38 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 50 votes

6.15.2.4 Skip header lines on import

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=50718

When importing a data file what are the comment symbols for Mathematica? 
That is, given a file like this 
 
blabla 
bulbul 
 
1 2 6 54 7 ... 
.. 
 
 
what symbol do I have to put in front of header lines so  ... 
[import] [text]
 

asked by MaxJ https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=14687 20 votes

answered by george2079 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2079 18 votes

6.15.2.5 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. 
 
Select[x, #>7&] gives the elements themselves, and Position[x,8] gives the  ... 
[list-manipulation]
 

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 65 votes

answered by J. M.'s technical difficultieshttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 62 votes

6.15.2.6 How to make an inkblot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3345

How to effectively create a polygon that looks like a realistic inkblot? So far, I could come up with this (borrowing from Ed Pegg Jr.'s Rorschach demonstration): 
 
RandomBlot[num_, opts___] :=  ... 
[graphics] [performance-tuning] [image-processing] [generative-art]
 

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 86 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 51 votes

6.15.2.7 How to generate a random snowflake

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39361

'Tis the season... 
And it's about time I posed my first question on Mathematica Stack Exchange. 
So, here's an holiday quest for you Graphics (and P-Chem?) gurus. 
 
What is your best code for generating  ... 
[graphics] [random] [simulation] [generative-art]
 

asked by Peltio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6745 140 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 181 votes