4.6.3 Can you answer these questions?

4.6.3.1 Nonsparse sparse array crashes kernel on windows

http://mathematica.stackexchange.com/questions/136835/nonsparse-sparse-array-crashes-kernel-on-windows

 
On win 10, 64 bit, version 11.0.1, my kernel just started crashing for no reason as for as I can see. Does/should the following crash your kernel? 
 
sparse = SparseArray[ArrayRules[RandomInteger[{1,  ...
 

- asked by Coolwater 6votes

4.6.3.2 How to visualize the vorticity of a 3D velocity field?

http://mathematica.stackexchange.com/questions/136917/how-to-visualize-the-vorticity-of-a-3d-velocity-field

 
I have a snapshot of a system with 50 particles. 
 
The snapshot is a list of 3 coordinates and 3 velocities per each particle. 
Namely, $(x,y,z,\dot{x},\dot{y},\dot{z})$, which AKA phase space  ...
 

- asked by 0x90 5votes

4.6.3.3 Finding line segments on the image by using ImageLines

http://mathematica.stackexchange.com/questions/136795/finding-line-segments-on-the-image-by-using-imagelines

 
There is an image from wolfram documentation 
 
 
 
I want to find and highlight lines on the following image 
 
 
 
I tried: 
 
img = Import["http://imgur.com/NbNwYWC.png"] 
 
lines = ImageLines[EdgeDetect[img],  ...
 

- asked by vito 3votes

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