4.23 Tuesday, July 18, 2017

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Top new questions this week: 
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[Is there concise code for the list operation I want to perform?] https://mathematica.stackexchange.com/questions/151550/is-there-concise-code-for-the-list-operation-i-want-to-perform

Is there any concise syntax for the following partitioning of a list. Given 1, 2, 3, 4, I want to get the output as shown below. I have tried various function such as Partition and others, but I ...

- asked by vikas (10 votes), answered by kglr (16 votes)

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[Animate Koch curve generation and include a transition effect] https://mathematica.stackexchange.com/questions/151621/animate-koch-curve-generation-and-include-a-transition-effect

Recently, I saw two kinds of animation of Koch curve iteration generation.

I don’t know how to make this effect, now I can only do this

Clear[koch]; 
koch[{A_, B_}] := 
  Partition[ 
    {A, (2 A  ...

- asked by mathe (10 votes), answered by Kuba (14 votes)

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[How to find the sum for each individual row in a binary matrix until the first zero is reached from left to right.] https://mathematica.stackexchange.com/questions/151396/how-to-find-the-sum-for-each-individual-row-in-a-binary-matrix-until-the-first-z

I have a 150 by 300 binary matrix. I would like to sum the 1’s for each individual row (from left to right) until the first zero is encountered. For example, if a given row is 1 1 1 1 1 1 0 0 0 1 0 0  ... 

- asked by Tiffany Visgaitis (7 votes), answered by eldo (8 votes)

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[Replace element in array by checking condition in another list] https://mathematica.stackexchange.com/questions/151293/replace-element-in-array-by-checking-condition-in-another-list

Im trying to escape doing double loops given the large number of items in the arrays.

I have two list with a format like this:

list1={{1,2,0},{1,3,0},{4,6,0},{2,3,0}} (*Third element of each item is  ...

- asked by Giovanni Baez (7 votes), answered by Carl Woll (8 votes)

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[Geometry computations add-on for Mathematica?] https://mathematica.stackexchange.com/questions/151304/geometry-computations-add-on-for-mathematica

I came across the problem of calculating the circumcenters of triangles symbolically within another algorithm (as well as possibly doing other similar geometry computations). I was hoping Mathematica ...

- asked by Grayscale (7 votes), answered by C. E. (10 votes)

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[Trace of the points of intersection of two moving curves] https://mathematica.stackexchange.com/questions/151325/trace-of-the-points-of-intersection-of-two-moving-curves

I would like to trace the points of intersection between the polar curves

r == Cos[n  + k t] 
 
 
and 
 
r == t Csc[] 
 
as t goes from -1 to 1. (n and k are constants, and y, r, and  relate in the  ...

- asked by 404UserNotFound (6 votes), answered by Carl Woll (11 votes)

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[How to delete the parameter of a Neural Network?] https://mathematica.stackexchange.com/questions/151591/how-to-delete-the-parameter-of-a-neural-network

Mathematica Neural Networks based on MXNet. And there is lots of model in MXNet(MXNet Model Zoo).

For example,I follow a tutorial An introduction to the MXNet APIpart 4, It uses Inception v3(net ...

- asked by partida (5 votes), answered by xslittlegrass (3 votes)

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

[Why should I avoid the For loop in Mathematica?] https://mathematica.stackexchange.com/questions/134609/why-should-i-avoid-the-for-loop-in-mathematica

Some people advise against the use of For loops in Mathematica. Why? Should I heed this advice? What is wrong with For? What should I use instead?

- asked by Szabolcs (52 votes), answered by Szabolcs (62 votes)

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[Image processing: Floor plan - detecting rooms’ borders (area) and room names’ texts] https://mathematica.stackexchange.com/questions/19546/image-processing-floor-plan-detecting-rooms-borders-area-and-room-names-t

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 ...

- asked by s.s.o (52 votes), answered by nikie (52 votes)

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

[Unexpected Behavior of Parametric Sensitivity in ParametricNDSolveValue] https://mathematica.stackexchange.com/questions/151294/unexpected-behavior-of-parametric-sensitivity-in-parametricndsolvevalue

While exploring alternative methods of solving 33538, I encountered difficulties with the parametric sensitivity capability of ParametricNDSolveValue. (Useful background on parametric sensitivity is ...

- asked by bbgodfrey (2 votes)

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[FindShortestTour suddenly runs far slower for large numbers of points] https://mathematica.stackexchange.com/questions/151513/findshortesttour-suddenly-runs-far-slower-for-large-numbers-of-points

I was doing a benchmark of FindShortestTour and I noticed something really weird. Around 10000 points, FindShortestTour suddenly takes 6 times as long without explanation:

times = Table[ 
    pts =  ... 

- asked by Jorge Perez (2 votes)

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[Manual CellGroups: problem with closing nested CellGroupData] https://mathematica.stackexchange.com/questions/151336/manual-cellgroups-problem-with-closing-nested-cellgroupdata

Background

CellGroupData second argument allows to specify which cells are visible. I faced problems though.

This example works well, the second group is not visible:

Notebook[{ 
   Cell @  ... 

- asked by Kuba (1 vote)