All Questions
85,073
questions
3
votes
0
answers
47
views
Symbols leak into Global context when using Information
When debugging I found the following peculiar behaviour of Information:
...
- 322
0
votes
1
answer
52
views
what is wrong in my code for calculate parameters bivariate distribution?
data is i,j as x, y as in pic
...
- 85
1
vote
0
answers
21
views
NDSolve error in Functional Delay Diff Eq
I'm trying to use Mathematica to study an equation that has an unusual dependence on past states, i.e. some kind of a Delay Diff Eq. For the sake of this post, we can say that the equation I would ...
- 203
0
votes
1
answer
44
views
Simulating/solving a Langevin equation with overdamped dynamics and plotting a phase space plot
I've been reading about the Langevin equation, specifically the case where we are dealing with overdamped dynamics.
I'd like to simulate the dynamics discussed in the second link and effectively ...
- 2,352
1
vote
2
answers
96
views
Evaluate an integral over a range of initial values
I have an integral that I would like to evaluate over a continuous range of lower limits and plot the result. I can't figure out how to tell Mathematica to do this.
$$Q_c(u) = \frac{2\pi}{c^2} \left(\...
- 35
0
votes
0
answers
24
views
3
votes
0
answers
76
views
How to get a stable solution of diffusion-convection PDE, while don't make to tiny mesh?
I'm trying to simulate a self-propelled particle diffusing on a disk. The direction of the self-propelled velocity$\vec{v_A}$ doesn't change, while it speeds up at the boundary and slows down at the ...
- 65
0
votes
1
answer
41
views
Define and do the following function using Mathematica 12. How can I do this?
I would appreciate it if somebody could help me with the following problem:
Define and do the following function using Mathematica 12. How can I do this?
$$f[x]=|x|(-1 \le x \le 2),f[x+3]=f[x]+1$$
- 199
1
vote
1
answer
174
views
How can we fix an incorrect form of data?
incorrdata=Import["https://www.dropbox.com/s/lk7wiutjf4bx5yk/DataX.dat?dl=1"];
How can I fix this data, it should be in the form {$a,\bf{b}$} where b is ...
- 3,199
2
votes
2
answers
236
views
Making space between two tables
How can we make space between two tables arranged in the columns and each table contains four columns? Kindy let me know? I want this kind of table. Kindly let me know. I want it in latex?
1
vote
0
answers
15
views
Touchpad rough scrolling in version 13.1 linux?
I changed from windows to linux (arch linux, endeavouros, kde, x11 (but wayland was not better)) and simultaneously from version 13 to version 13.1 and the scrolling is rather difficult with the touch-...
- 532
3
votes
2
answers
135
views
BoundaryMeshRegion Error: Boundary surface is not closed
I am trying to create a BoundaryMeshRegion comprised of many cubes with random locations, in a relatively small region.
I have had success implementing my technique for a smaller number of cubes (say,...
- 353
0
votes
1
answer
51
views
How to find maximum likelihood parameter estimates for a custom bivariate distribution?
this is univariate distribution
...
- 85
1
vote
1
answer
40
views
How to better display the data using ComplexListPlot?
I'm trying to plot the solution of the equation with ComplexListPlot but the plot of the data points are small and hard to see.
Do you have any idea to display it better and easier to see the data?
<...
- 2,392
3
votes
2
answers
85
views
Understanding HoldAll?
Suppose I try to run the following code:
f[x_] := Cos[x]
F[X_] := Normal[Series[f[x], {x, X, 5}]]
Plot[Table[F[n], {n, -5, 5, 1}], {x, -Pi, Pi}]
Mathematica will ...
- 4,841
0
votes
1
answer
82
views
Find roots of a system equation involving Bessel functions
I'm trying to find the roots (a_n,b_n) of a system involving Bessel functions.
I tried to obtain a list of the n-first roots in mathematics with FindRoot, but I only get one root, how can I get the ...
7
votes
2
answers
142
views
How to bound a set of data points from above?
The following data produces a distribution as shown. However I want that black-line to be highlighted that is kind of bounding these points from above. How can one do this in Mathematica?
...
- 497
1
vote
0
answers
21
views
How can I get a BarLegend for ImageDisplacements?
I'm trying to compute Optical flow using ImageDisplacements.In the example given in the documentation, there is a figure showing the levels of displacement. How can I get a Barlegend or something ...
- 73
0
votes
0
answers
34
views
Wolframscript throwing InvalidPointer [closed]
I'm running a wolframscript script on a computer cluster. My process exits after about 8 hours of execution with the following messages printed to terminal:
Killed
terminate called after throwing an ...
- 557
1
vote
1
answer
52
views
Plot graphics frame Issue
Bug introduced in 13.0 and persisting through 13.1
With Mathematica 13.1 I see the following issue with the right side frame changing based upon the number of elements plotted. Specifically, with ...
- 313
3
votes
0
answers
44
views
First few smallest eigenvalues of a large dense symmetric matrix
I construct a large (say 2000x2000) matrix M whose entries are real random variables drawn from a certain distribution. Most of these values will be nonzero, so <...
1
vote
2
answers
60
views
Repeated roots/solutions for a numerical solution
Consider the equation,
$x^2 + e^x + y^2 + y = 4, -2 \leq x \leq 2$
Solve for $y$ numerically using FindRoot
My attempt:
...
2
votes
1
answer
65
views
Slow integration of trigonometric expression speeds up after TrigReduce
I'm trying to integrate a trigonometric expression as
Integrate[Cos[2 t] Cos[3 t] Cos[4 t] Cos[5 t] Sin[2 t] Sin[3 t], {t, 0, 2 Pi}]
The final results is correct (...
- 21
2
votes
2
answers
83
views
How to prevent overwriting the latest output
Suppose I have a long notebook with three parts:
...
- 322
0
votes
0
answers
43
views
Why do I get different result when trying to solve the same problem with one Solve and two Solve?
first way which gives out the result very quickly:
...
- 111
0
votes
0
answers
38
views
How can I solve this given Partial Differential Equation (PDE)?
I build this PDE from the physics, the equation and the value of all parameters are like this:
...
- 135
0
votes
1
answer
64
views
How to optimize code for obtaining large data set?
In an application, I need to find a region where some conditions must be true. However, these conditions are made of interpolating function solved by ParametricNDSolve. I will give a toy model example ...
- 1
0
votes
1
answer
95
views
Plot eigenvalues of a matrix with two variables [closed]
I am trying to plot eigenvalues E(kx,ky) of the matrix [mat] depends on two variables kx and ky and of course n its dimension , and the matrix elements a, b and c depend on cos(kx) ; cos (ky) and cos(...
- 19
3
votes
1
answer
80
views
How to call the librarylink api in 13.1
Local file demo.c have some library link API example, such as:
example 1:
...
- 24.5k
4
votes
1
answer
68
views
Ordered list of integer vectors
For a given length $n$ and a maximum positive integer value $N$, I'd like to generate a list that contains all $n$-vectors with entries between $-N$ and $N$ (of which there are $(2N+1)^n$. Further, ...
- 91
3
votes
2
answers
63
views
Unable to use KnotTheory
I've installed the KnotTheory package, following the instructions here. But when I try to use it I get this error:
...
- 31
0
votes
1
answer
68
views
Splitting a data set into multiple parts
The Problem
I am trying to split a data set into multiple parts - thanks to help in the past, this has been done before into 2 parts, but I would like to extend this functionality into multiple parts (...
- 471
4
votes
1
answer
65
views
How to use Import[] to grab text displayed on a Twitter page for a non-existent username?
Let's say http://www.foo.bar/?domain=wibble returns a search page on the word "wibble" provided by an engine with the frontdoor address ...
- 151
3
votes
1
answer
51
views
bV diagram of TE modes guided by waveguides with a linearly tapered index profile
I have an equation and I have tried solving it to find values of $b$ but it doesn't give me the same figure as in the book Foundations for guided-wave optics by Chin-Lin Chen.
The equation that I have ...
- 31
2
votes
3
answers
77
views
2
votes
1
answer
54
views
How to plot the graph between Q and J? Where, Q and J are variables
How to plot the graph between Q and J for the following equation? Here we can take $l$ = 1.
$\frac{\pi Q^2 + \sqrt{\pi^2 Q^4 + \frac{16 J^2}{l^2} }}{8} + \frac{2 J^2}{l^2 \bigg(\sqrt{\pi^2 Q^4 + \...
3
votes
1
answer
129
views
Dsolve cannot solve this nonlinear ODE system
when I run this, I get "Supplied equations not differential or integral equations of the given functions" although the solution for this initial conditions is x = [sin(t),0,cos(t),0]. Why ...
- 53
1
vote
3
answers
64
views
How to restrict FindDistribution to real-valued distributions
The following seems buggy to me, but perhaps I'm confused about something. Or maybe there's a workaround that makes it moot?
First, I ask Mathematica to find a distribution that describes a dataset ...
- 606
0
votes
0
answers
46
views
Using DSolve, For A System With A Piecewise Function, And For Given Boundary & Continuity Conditions
I'm trying to solve a system of ODE's, analytically, to find the integration constants.
The system is the following (with zUpper=125 000 and zLower= 200 000).
For 0 <= z <= zUpper:
3 T''[z] == 0....
- 81
0
votes
0
answers
33
views
LyapunovSolve does not give me the correct answer
I am trying to solve an equation using LyapunovSolve, but it does not give me the correct answer. The correct answer should be a 6*6 matrix while by utilizing the Dimension command, it shows me {2}.
...
3
votes
2
answers
88
views
Partition the list by group of Arithmetic Progression
I have a list= {4, 8, 10, 11, 12, 14, 16, 7, 9}
How can i partition the list by group of Arithmetic Progression with common difference 1 :
{{4}, {8}, { 10, 11, 12}, {14}, {16}, {7}, {9}}
- 417
6
votes
3
answers
243
views
Replace items of list except items that are member of another list
I want to replace all items in li1 that are not members of li2 with x.
...
- 2,842
4
votes
1
answer
88
views
How to import and render this OBJ file with correct texture?
Here's the output of a 3D scan of a bike, I need to render it in color with the texture file provided. Here are the files:
...
- 30.6k
3
votes
2
answers
39
views
GraphicsColumn - Multiline text isn't adapting based on overall column size
I'm trying to use Graphics Column to add a label under my plots. Eventually these individual columns will be combined in a grid, and I want the height of each plot to be the same so I can compare data ...
- 63
4
votes
0
answers
62
views
2
votes
1
answer
99
views
How to get the graph of this function?
Found the animation of this graph (without code) and its function
And I just need a graph, not an animation. How to do it? It's just "Plot" or what?
I mean, I'm confused, because I don't ...
- 33
1
vote
1
answer
82
views
Derivative of long expression renders Piecewise[…<<…>>…] in Jupyter notebook
My mathematical problem is to solve the optimization problem:
$$ Max_{u} \quad \mathbb{E}[\gamma S-S^2]$$
where $$S= A_0 u X+a-\max(\alpha u X+b,0)$$
with $\gamma,A_0,a,\alpha,b$ some constants and $X\...
- 123
4
votes
2
answers
115
views
latex in a label
I am trying to draw an arrow, and put two labels next to it, and the labels, namely e_2, and a(e_2) should be in latex format.
...
- 41
3
votes
4
answers
289
views
Factorial implementation using FixedPoint
I implemented the factorial function:
fact[0] = 1
fact[x_Integer?Positive ] := x*fact[x - 1];
f[4] yields 24 as expected
I tried a different version of the ...
- 1,086
5
votes
0
answers
62
views
Why the ComplexExpand is not working here?
The ComplexExpand seems not to be working in the following where all variable are real:
...
- 497