1.15 Thursday, January 28, 2021

1.15.1 Top new questions this week

What’s the difference between these 2 associations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238880

I have 2 associations similar to these simplified ones:

asked by Coolwater https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9754 16 votes

answered by Leonid Shifrin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81 16 votes

How can I handle graphics or artworks with millions of points?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238735

As a hobby, I am trying to use Mathematica and Wolfram Language as a tool for making generative artworks. Generative art techniques may require drawing millions of points, lines, or curves. For ...

asked by mikabozu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74721 15 votes

answered by George Varnavides https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41179 21 votes

ContourPlot3D, grid of cylinders

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238849

I am trying to make a 3D contour plot that looks like a grid of cylinders to represent the Fermi surface of a metal, like below:

I have no problem generating something that kind of looks like it.

asked by Nick https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76998 10 votes

answered by cvgmt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72111 13 votes

Distorting image to ensure consistent vanishing point

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238742

Here’s Giorgio de Chirico’s painting, Ariadne:

The Surrealist artist deliberately broke the rules of geometric perspective, giving the work his characteristic sense of mystery and unease. What would ...

asked by David G. Stork https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9735 10 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 2 votes

Export infinite looping GIFs by default

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238591

frames=Table[Plot[Sin[x(1+a x)],{x,0,6}],{a,0,2,0.2}]; 
Export["test.gif",frames]

The above code runs in version 9.0 to get a infinite looping GIF ...

asked by expression https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7339 10 votes

answered by Kuba https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5478 7 votes

Replace a color in image with hatchfilling

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238687

Is it possible to identify a color (say grey in a 3 color Black, Gray and White image) and ...

asked by skyfire https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70181 9 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

MeshRefinementFunction on 2D surfaces embedded in 3D

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238705

DiscretizeRegion doesn’t seem to run the supplied MeshRefinementFunction when meshing a 2D surface in 3D. For example:

asked by alessandro https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42454 7 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 3 votes

1.15.2 Greatest hits from previous weeks

How do I identify the source of a "Tag times protected" error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11982

I have some code that looks like

Table[ 
    a = 1; 
    b = {2, 3} 
    c = i;, 
    {i, 2} 
] 
 
which gives an error: 
  Set::write: Tag Times in c {2,3} is Protected....

asked by dearN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=204 29 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 35 votes

Labeling individual curves in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4444

I need to create a plot for export and inclusion in a report. Is there a better way to label curves than PlotLegends? From what I’ve read and my personal experience,...

asked by Tianxiang Xiong https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1041 63 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 47 votes

How to add a vertical line to a plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3561

In the plot below I would like to add two vertical lines at \(x = \frac {\pi }{15} \pm \frac {1}{20}\). How can I do that?

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 61 votes

answered by Ajasja https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=745 82 votes

Drawing a square root spiral

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66969

Here is a start. I’m looking for a nice way to draw it.

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 24 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 21 votes

Multivariable Taylor expansion does not work as expected

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=15023

The basic multivariable Taylor expansion formula around a point is as follows:

asked by matheorem https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4742 63 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 71 votes

Solving \(L=\frac {3}{2} \sqrt {4 \pi ^2 A^2+W^2}-\frac {\sqrt {5 W \sqrt {4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt {2}}+\frac {3 W}{2}\) for \(W\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=57763

When I solve the aforementioned equation for \(W\) or \(A\) on Mathematica I get a long and ugly equation in return, namely one of the solutions for \(W\) is: (attempt to read at your own health)

asked by J.D’Almbert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19257 8 votes

answered by Alexei Boulbitch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=788 15 votes

Mathematica command that allows it to read my intentions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=194384

In version 2.0 of Mathematica there was a command, ReadProgrammerIntentions[ ] which allowed it rapidly compose code that could solve problems simple to complex, ...

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 52 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 38 votes

1.15.3 Can you answer these questions?

How to improve this code?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238887

The aim of my work is to find a value for the complex constant \(\omega \). In order to do that I solve the below system of differential equations with a manual shooting method: I first solve the system ...

asked by mattiav27 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8822 3 votes

Error on DSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238596

I’ve been trying to solve this initial value problem using DSolve[]: \[ \frac {dy}{dt}=1+t\space \sin (t\space y),\quad y(0)=0, \quad t=[0,2] \]

asked by Walser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60465 1 vote

answered by Mariusz Iwaniuk https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26828 0 votes

Remove defect of display in ListDensityPlot3D

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=238719

I have a 3D volumetric data (for example, \(64\times 64\times 64\), at each point there is a value) read in from a file and I want to use ListDensityPlot3D to ...

asked by Dennis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69969 1 vote