4.25 Tuesday, July 4, 2017

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Top new questions this week: 
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================================== Top new questions this week: ==================================

[Is there a simple and fast way to delete dependent lines of a matrix] https://mathematica.stackexchange.com/questions/149281/is-there-a-simple-and-fast-way-to-delete-dependent-lines-of-a-matrix

I am building a matrix, but some of the lines are dependant. I would like to only keep independant lines (so erase all lines that depend from another).

I could compute the nullspace of the transpose ...

- asked by StarBucK (10 votes), answered by george2079 (10 votes)

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[Vertex coloring for bi-connected graphs] https://mathematica.stackexchange.com/questions/149247/vertex-coloring-for-bi-connected-graphs

In graph theory, a bi-connected component is a maximal bi-connected subgraph of a graph \(g\)–i.e., a connected subgraph that would remain connected if any one of its vertexes were to be removed. An ...

- asked by David G. Stork (10 votes), answered by kglr (9 votes)

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[Compile and uncompilable function bug?] https://mathematica.stackexchange.com/questions/149343/compile-and-uncompilable-function-bug

I think I found a bug, but I still have MMA version 11.0.1 installed. Can somebody please check if this persists in the latest version?

When I compile this function:

cf = Compile[{{n, _Integer}}, 
   ...

- asked by JEM_Mosig (10 votes), answered by Michael E2 (12 votes)

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[How to make the result of InputForm balance the bracket] https://mathematica.stackexchange.com/questions/149558/how-to-make-the-result-of-inputform-balance-the-bracket

I always use InputForm to check the result object,such as Dataset or Graphics or other objects.But if you are in the result of InputForm,you cannot use the Front-End function of balance the bracket. ...

- asked by yode (9 votes), answered by Carl Woll (6 votes)

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[KeyValuePattern in matching and replacement in nested associations] https://mathematica.stackexchange.com/questions/149402/keyvaluepattern-in-matching-and-replacement-in-nested-associations

This case revealed I am missing something in pattern matching and evaluation in case of match, or I can’t grasp it due to the busy week I have. Either way, I find this problem interesting for wider ...

- asked by Kuba (9 votes), answered by Mr.Wizard (5 votes)

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[Align two images with respect to sperm head] https://mathematica.stackexchange.com/questions/149280/align-two-images-with-respect-to-sperm-head

My biologist friend has to align sperm images according to their heads. He usually does that manually by rotating each image. The problem is that there are so many images and it takes a lot of time. ...

- asked by Anjan Kumar (9 votes), answered by nikie (7 votes)

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[A more convenient Fourier series] https://mathematica.stackexchange.com/questions/149468/a-more-convenient-fourier-series

Personally, I feel the design of FourierSeries/FourierSinSeries/FourierCosSeries/FourierTrigSeries not convenient enough because:

They can’t give general formula of series as output, one must set a ...

- asked by xzczd (7 votes), answered by xzczd (7 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 (51 votes), answered by Szabolcs (61 votes)

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[My Girlfriend is going to prison...Save her with Math] https://mathematica.stackexchange.com/questions/135937/my-girlfriend-is-going-to-prison-save-her-with-math

Salacious title, but true story.

 dmethyl1 = { 
      {0, 0}, 
      {.25, 1}, 
      {.5, 7}, 
      {1, 26}, 
      {1.5, 40}, 
      {2, 45}, 
      {2.5, 45}, 
      {3, 44}, 
      {3.5, 44}, 
      {4,  ...

- asked by Prisoners Dilema (39 votes), answered by bobthechemist (24 votes)

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

[Serious regression in Integrate in 11.1.1? Division by zero generated] https://mathematica.stackexchange.com/questions/149495/serious-regression-in-integrate-in-11-1-1-division-by-zero-generated

What is going on here? In version 11.1.1 on windows 7

Using Version 11.0.1 also on windows 7

Source code

ClearAll[x, n, c, a ,b] 
Integrate[(a + b*(c*x^n)^(2/n))^3, x]

Why does ...

- asked by Nasser (7 votes)

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[Hiding inputs with specific function] https://mathematica.stackexchange.com/questions/149298/hiding-inputs-with-specific-function

I believe this question could be a duplication, but I did some searches with the term "hide the input cell", but none answered me. Only inputs with this function.

I have several input cells using the ...

- asked by LCarvalho (3 votes)

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[Gravitational Lensing Simulation, Coordinate and Rendering Issues] https://mathematica.stackexchange.com/questions/149447/gravitational-lensing-simulation-coordinate-and-rendering-issues

I am trying to replicate this gravitational simulation online application called LensToy using Mathematica instead. I have two issues.

First, unlike LensToy, my rendering is extremely slow and drives ...

- asked by mpourrah (2 votes)