1.4 Thursday, April 29, 2021

1.4.1 Top new questions this week
1.4.2 Greatest hits from previous weeks
1.4.3 Can you answer these questions?

1.4.1 Top new questions this week

Replacing duplicates instead of deleting them
RecurrenceTable and While
Speed up averaging of numerically solved differential equations
FEM: how to redo a composed boundary mesh for better quality?
Were these Images made with Wolfram Language / Mathematica?
How to find the repeated elements in a vector
How to separate two regions in DensityPlot

Replacing duplicates instead of deleting them

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245078

My code replaces each repeated element by "X".

asked by azerbajdzan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53172 10 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 18 votes

RecurrenceTable and While

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2450308

Good day. Let’s take an example from Help on RecurrenceTable

asked by macros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=79485 6 votes

answered by Roman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26598 3 votes

Speed up averaging of numerically solved differential equations

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245121

I deals with a coupled system with non-linear differential equations of first order. I perform numerical solution with NDSolve and then use obtained solutions,

asked by Artem Alexandrov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49992 5 votes

answered by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 1 vote

FEM: how to redo a composed boundary mesh for better quality?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245050

Suppose you have region with 2 materials: one embedding material matrix containing some particles

asked by Mauricio Fernández https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24710 4 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 5 votes

Were these Images made with Wolfram Language / Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245080

I am currently writing a paper in which Fibonacci Spirals are discussed. In the text of the paper the mathematics of these objects is discussed and the relevant equations and relationships are shown ...

asked by urquiza https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=79636 4 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 9 votes

How to find the repeated elements in a vector

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245068

Is there a way to write a function where the input is a vector and the output is the elements in the vector that are repeated? I was trying to use something along the lines:

asked by Trashlife https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=79628 4 votes

answered by Roman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26598 7 votes

How to separate two regions in DensityPlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245051

I want to separate two regions in DensityPlot similar to the attached image.

In my code and the obtained result, I want to separate the region with less value of one from others. How can I do this? ...

asked by mehrosadat ebrahimi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=40575 4 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 4 votes

1.4.2 Greatest hits from previous weeks

How to graph a sphere with cartesian equations?
Parallel and perpendicular symbol from Mathematica to LaTeX
How do I make a 3DPlot using cylindrical coordinates?
What does Compile[] do to make code run so much faster?
How do I clear all user defined symbols?
Formatting legend text font
How can I plot the direction field for a differential equation?

How to graph a sphere with cartesian equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=24169

I’m new to Mathematica and I need to ask how to graph a sphere, cylinder, etc.. using cartesian equations.

For example in sphere’s case \(x^2+y^2+z^2=1\)

I tried to use ...

asked by German https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7145 8 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 14 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

\[ \begin {bmatrix} E_{\parallel } \\ E_{\perp } \end {bmatrix} \]

I have tried to use inbuilt ’symbol’ character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 20 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 27 votes

How do I make a 3DPlot using cylindrical coordinates?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19076

I’m trying to plot a function of the form \(z(r,\theta )\) where \(r \in [0, R]\) for a finite R, \(\theta \in [0,2\pi [\), and z is the third coordinate, a function of the first two. I couldn’t find anything ...

asked by Learning is a mess https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5643 19 votes

answered by whuber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=91 26 votes

What does Compile[] do to make code run so much faster?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2371758

I am looking for an ELI5 explanation of whatCompile[] in the Wolfram Language context does and why it works so much faster than uncompiled code in certain cases. I am trying to get more insight to ...

asked by anon248 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66458 20 votes

answered by chasly - supports Monica https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34024 9 votes

How do I clear all user defined symbols?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=850

Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?

asked by niklasfi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=82 99 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 98 votes

Formatting legend text font

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3433

I am using this code to plot a graph, and I am trying to make the font of the legend bigger.

asked by Julia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=525 20 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 25 votes

How can I plot the direction field for a differential equation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8841

I’d like to plot the graph of the direction field for a differential equation, to get a feel for it. I’m a novice, right now, when it comes to plotting in Mathematica, so I’m hoping that someone can ...

asked by Matt Groff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1735 33 votes

answered by Peter Breitfeld https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=307 26 votes

1.4.3 Can you answer these questions?

Artifacts When Plotting Results of Numerical Integration
How to solve a system with infinitely many equations?
Custom multiplication operation between variables

Artifacts When Plotting Results of Numerical Integration

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2451018

I am trying to reproduce the following graph of phase shifts as function of frequency.

Please see my code bellow. I used Mathematica to solve for t1 and ...

asked by guestuser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76488 2 votes

How to solve a system with infinitely many equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=245194

I need to solve the following system of (infinitely many) equations. I am looking for \(V(0,0)\)

\(t \in \{0,1,2.....\}\) with one caveat that \(s \leq 1+t\) should hold.

\( s \in \{1,2,3,L-1\}\)

fixed ...

asked by Monire Jalili https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=62240 1 vote

Custom multiplication operation between variables

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2452988

I am constructing polynomial expressions in the variables \(s[0],s[1],...,s[n]\) and I’m trying to define a new operation to simplify the expression:

asked by David https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72836 1 vote