6.4.1 Top new questions this week

6.4.1.1 Wrong function of NotebookDirectory[] in the 12.1 version

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219700

Bug introduced in 12.1.0 
 
 
 
Could anybody help? 
 
NotebookDirectory[] function began working wrong in 12.1 (the bug was not present in 12.0 and earlier versions). 
 
When folder name includes Russian  ... 
[bugs] [notebooks]
 

asked by Alexander https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72011 13 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 10 votes

6.4.1.2 How complete is the WL's string language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220003

Consider the following example: 
 
Suppose I am interested in words that contain all the letter of the list characters={"e","t","l","a","b"} at least once. An example would be the word "abilities" or a  ... 
[string-manipulation]
 

asked by user13892 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13892 12 votes

answered by Jason B. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9490 11 votes

6.4.1.3 Reusing PARDISO symbolic factorization

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219687

Is there a way to do this natively in Mathematica? I read in several places that this is possible with LibraryLink, but I don't have a lot of experience with C and so I'm having trouble implementing  ... 
[equation-solving] [linear-algebra] [sparse-arrays] [interoperability]
 

asked by beets https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72007 8 votes

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 13 votes

6.4.1.4 How to Improve FEM Solution with NDSolve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219990

First some comments. This same calculation works beautifully in 2D with essentially the same code. I have copied it largely unaltered into 3D as part of a migration to 3D so that I can do more complex  ... 
[differential-equations] [finite-element-method]
 

asked by Paul Harrison https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69377 7 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 8 votes

6.4.1.5 What is the difference between Wolfram Script and Wolfram Engine?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219963

I don't understand the difference between these products: 
 
Wolfram Script 
 
Wolfram Engine 
 
Would someone help me understand what these are?  And how it differs from just using Mathematica in the  ... 
[scripting]
 

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 6 votes

answered by morbo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=48686 0 votes

6.4.1.6 Implicit Riccati Equation Solver (to find the anti-stabilizing solution)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219758

I've found that the latest MATLAB icare() solver includes the possibility to find also the anti-stabilizing solution of the Riccati equation. 
I haven't found a similar option on Mathematica. Is there  ... 
[equation-solving] [matrix] [linear-algebra] [undocumented] [control-systems]
 

asked by Mirko Aveta https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36621 6 votes

answered by Suba Thomas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5998 5 votes

6.4.1.7 Dates not printed in DateListPlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220154

A simple example 
 
Clear["Global`*"]; 
 
data = TimeSeries[{1, 2, 1, 3, 0, 0, 0, 2, 21, 15, 21, 7, 11, 5, 10, 
18, 73, 38, 103, 21, 35, 31, 46, 31, 35, 94, 71, 48, 78, 71, 74, 
95, 95, 56,  ... 
[plotting] [date-and-time]
 

asked by Vaggelis_Z https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5052 5 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 1 vote