7.16.1 Top new questions this week

7.16.1.1 Finding "chains" of numbers in a matrix

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245937

To give some context, this problem is related to music theory. 
I have a matrix I'm generating with this code: 
... 
[discrete-math]
 

asked by Eriek https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18649 6 votes

answered by thorimur https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=63584 9 votes

7.16.1.2 How to formulate this problem in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245908

Say, I have the following expressions 
 f = R[p] 
g = S[p] 
 
where R,S are rational functions, and I want to find a polynomial such that 
... 
[equation-solving] [functions]
 

asked by nilo de roock https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=156 6 votes

answered by Roman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26598 11 votes

7.16.1.3 Problem with optimal control and Pontryagin's maximum principle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245797

For dynamic system: 
$\dot{x}=\frac{df}{dx}+u$ 
where $f=e^{-x^2}$ 
It is necessary to develop optimal control, minimizing criterion: 
$J= \int_{0}^{t_f} ((\frac{df}{dx})^2+u^2) \,dt $ 
Algorithm: 
 
We ... 
[differential-equations] [equation-solving] [mathematical-optimization] [nonlinear] [control-systems]
 

asked by dtn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=67019 6 votes

answered by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 7 votes

7.16.1.4 Sorting Associations by DayName (day of week) using KeySort and/or KeySortBy

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245721

I have an association where the keys are the days of the week: 
... 
[associations] [date-and-time]
 

asked by theorist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45215 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 6 votes

7.16.1.5 Using the PowerPoint's laser pointer in symbols of plots

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245800

I am interested in exploiting a symbol that is similar to the PowerPoint's laser pointer in the role of  PlotMarkers . Is there any idea to create that!? 
This symbol ... 
[plotting]
 

asked by Inzo Babaria https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=33967 5 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 12 votes

7.16.1.6 How would one add Hyperreals as a new type to Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245782

Hyperreals are an extension to the real numbers; they formalise the concepts of infinities and infinitestimals as numbers, rather than the named limit points outside of the system of reals and form ... 
[number-representation] [custom-notation] [real]
 

asked by Julian Moore https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12858 5 votes

7.16.1.7 Extract held value from Association

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245784

Consider an association which contains a key which must not be prematurely evaluated. 
 assoc = <| key :> value |> 
 
For example, a value of ... 
[evaluation] [associations] [hold]
 

asked by Anti Earth https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=32591 5 votes

answered by Leonid Shifrin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81 6 votes