All Questions
84,518
questions
0
votes
0
answers
5
views
Is it possible to make Mathematica find a solution to this first order system of nonlinear ODE?
The first order system of 4 coupled ODE with trigonometric terms is the following:
$$
\begin{array}{rcl}
\dot x(t)&=&y(t)\\
\dot y(t)&=& -A \sin(x(t))+\frac{v(t)}{B}\\
\dot u(t)&...
- 745
0
votes
0
answers
5
views
Error Meshing with ToElementMesh (ToElementMesh: Cannot set region holes.) for certain objects
I have had a problem properly meshing certain .obj files, where others are meshed successfully.
Here is an example of a successfully meshed .obj:
Whereas, using the code at the bottom which includes ...
- 105
4
votes
1
answer
31
views
Layout improvements for planar graph
I recently used Cage software to generate a 24-vertex planar graph. All details of the graph are as follows, including the coordinates of each of its vertices. I know it is 3-connected.
...
- 847
0
votes
0
answers
15
views
How to improve the accuracy of integration with Bessel function without significant drop in performance?
Consider the following function and integral:
...
- 3,832
0
votes
1
answer
31
views
RegionDifference Fails at Two Simple Cubes
Or, maybe, I just dont get it right.
I got two simple mesh cubes:
...
- 121
0
votes
1
answer
31
views
How to make this kind of integration with the trigonometric function?
I am trying to make the following integration. But I am not sure about the result obtained as follows.
Is there some way to get more reliable and accurate results?
Thanks.
...
- 1,217
0
votes
1
answer
32
views
Why are the results different when I integrate an expression in different ways?
When I integrate the expression like,
...
- 61
0
votes
0
answers
21
views
Difference in the output of NIntegrate versus Integrate
I have an expression which when integrated, should be a cumulative distribution function (CDF). I have integrated the expression using both NIntegrate[] and Integrate[]. When the CDF returned by ...
- 187
1
vote
1
answer
36
views
Sorting of a list of lists - i.e. list of matrices - what is the order of the sort determined by?
In the documentation we have:
Sort[list] sorts the elements of list into canonical order.
Maybe I am missing something but what does "canonical order" mean for sorting a list of matrices?
...
- 505
1
vote
1
answer
34
views
Two dimensional histogram with HistogramList
I have been trying to prepare a 2D histogram from a 2D-list; the dataset is:
data=RandomVariate[NormalDistribution[0, 1], {200, 2}];
if I do
...
- 25
4
votes
3
answers
46
views
fill region between horizontal lines and curve
I would like to fill the region between two horizontal lines and two curves like this
...
- 41
3
votes
1
answer
28
views
Contour lines on a torus not joining up
I have created a set of contour lines on a torus, but am unable to make some of them join up, even when increasing the number of points dramatically. Is there a sensible way to do this?
...
- 2,955
0
votes
0
answers
20
views
Any idea how to use Sub Mathematica license tokens?
I use mathematica with remote kernels for which my workplace has a bunch of tokens. There are 50 tokens for Sub MathKernel which I know how to use, with some ...
- 265
0
votes
2
answers
32
views
0
votes
1
answer
25
views
Error in evaluating a For loop
I defined an integral function and for solve it, I want to calculate it for some numbers and then plot its behavior. So I put the function in a For loop to automate this procedure and then plot the ...
2
votes
2
answers
38
views
Evaluating sums with spherical Bessel functions
I'm running Mathematica 13.0, student edition, on Windows. In physics, the total scattering cross-section of plane waves off a hard sphere of radius $1$ is
$$\sigma(k) = \frac{4 \pi}{k^2} \sum_{l=0}^\...
- 159
7
votes
1
answer
167
views
Fourth order, nonlinear PDE dipicting dynamics of liquid lenses
PROBLEM STATEMENT
Recently, I was trying to verify the solution of a set of thin film spreading equations given by this paper.
Where
$$p1=-(h_{1xx}+\sigma h_{2xx})$$
$$p2=-\sigma h_{2xx}-\Pi[h2-h1]$$
...
- 143
2
votes
1
answer
96
views
How can I manually adjust or align the position of each legend?
How can I manually adjust the position of each line legend (and for example align these pairs)? The legends become not aligned when the text lengths are different.
...
- 21
0
votes
0
answers
33
views
Exponents in my Nest?
While playing around with nests I got an answer from WolframAlpha that I can not quite comprehend. For reference I was inputting power towers in Nesting form.
Nest$[x^{\#1} \&, 1, 2]$ For example. ...
0
votes
0
answers
25
views
How to get Excel cell dependents from other sheets in the same workbook?
I have an excel file with two sheets Sheet1 and Sheet2.
In 'Sheet1'!C14 I have a formula <...
- 8,337
-2
votes
0
answers
51
views
POWERPOINT TO MATHEMATICA DEMONSTRATION? [closed]
I have a lengthy, detailed, well-made power point demonstration. How do I convert my power point to a Mathematica Demonstration? I tried copy pasting each of my power point slides into a Mathematica ...
- 135
4
votes
2
answers
81
views
How to map a function across multiple ragged lists
Preliminaries
I have lists that are lists of lists (i.e., each list contains one or more sublists and are ragged (i.e., each sublist can have a different length, though all have a length of 1 or ...
- 9,475
0
votes
0
answers
52
views
Proving a system of ODEs exhibits damped oscillations?
I have the following system of ODEs:
$\frac{dH}{dt}=Y(1-cg)(1-\frac{H}{HMax})g-aH$
$\frac{dY}{dt}=Y(1-cg)(1-\frac{H}{HMax})g+Y(1-cg)\frac{H}{HMax}-Y\frac{(X+Y)}{K1}$
$\frac{dX}{dt}=X\frac{H}{HMax}-X\...
- 391
9
votes
2
answers
203
views
Number of significant digits in uncertainty of Around
Around[100.123456, 0.12]
gives
100.12±0.12
But
Around[100.123456, 0.42]
gives
...
- 15.9k
1
vote
0
answers
46
views
Are there any function in Mathematica that is similar to pcolor in Python [closed]
I am trying to plot a colormap with Mathematica.
My dataset has a 1D array of length A which provides x-axis values, and a 1D array of length B which provides y-axis values, and a 2D array of size A*B ...
1
vote
1
answer
143
views
AbsoluteTime::ambig: Warning: the interpretation of the string 11-12-2020 as a date is ambiguous
TScci30clean = TimeSeries[cci30clean[[2 ;;]]]
I dont understand why this shows an error ,i have changed the date format twice in excel sheet that im working on ...
0
votes
0
answers
31
views
Complex Airy function implementation in Mathematica? [closed]
Which algorithm does Mathematica use for double-precision N[*,16] computation of the AiryAi and AiryAiPrime functions?
Are there any references?
Any TOMS number or libraries?
- 53
4
votes
1
answer
73
views
How to plot both x and y error bars? [closed]
It used to be possible to plot both horizontal and vertical error bars ErrorlistPlot and ErrorBars. However, this has been removed since version 12. It seems that Around only allows vertical error ...
- 125
2
votes
3
answers
388
views
How to get a white circle with a black border using "Graphics"?
I want a white filling inside the black dot
Graphics[{Black, FillingStyle -> White, PointSize[0.035], Point[{1, 2}]}]
- 23
0
votes
0
answers
33
views
Evaluate a fit as a function of an argument
I'm trying to manipulate the following function:
...
- 481
1
vote
0
answers
40
views
Error when fitting experimental data containing zero with a log model
I am trying to fit a set of experimental data with a model using NonlinearModelFit, but I receive an error message that I have been unable to fix. The error message I receive is shown below. Please ...
- 11
1
vote
0
answers
39
views
A piecewise inequality not simplified to True
In = Simplify[-a + Piecewise[{{-b, t > c}}] < 0, {a > 0, b > 0, c > 0}]
Out = Piecewise[{{-b, t > c}}] < a
Why the result is not evaluated to ...
- 115
6
votes
1
answer
81
views
Curved edges with GraphElementData no longer working in Mathematica 13.1
I just noticed that it seems no longer possible to get curved edges on graphs in Mathematica 13.1 using GraphElementData. For example, the following code works on versions 12.x:
...
0
votes
0
answers
42
views
Using MultiNonlinearModelFit with complex data
This is my first question, I'll try to formulate the problem first.
I have a complex function f[z] of a complex argument z which I calculate in Fortran for any z ...
- 1
3
votes
1
answer
64
views
Keeping mesh coordinates unchanged for Implict Region [duplicate]
I am trying to generate a 3D mesh for Finite Element simulations. I need to provide some precomputed inputs to the mesh points and will like my mesh to be the same for a given shape. However, ...
- 31
0
votes
1
answer
51
views
CylindricalDecomposition with symbolic variables
CylindricalDecomposition is a powerful function that can (for instance) compute the limits for each variable in integrals over a region. Suppose the region is:
<...
- 36.2k
0
votes
2
answers
98
views
NONLINEAR EQUATIONS cannot get the solution
I have simplified the equations and decrease the variables to 5, and changed the parameters' value as I think the equations in enter link description here is because of the improper parameters' value.
...
- 15
0
votes
1
answer
48
views
How to solve this initial boundary value problem for heat conduction equation?
I want to solve the following PDE:
heqn=D[u[x,t],t]==D[u[x,t],{x,2}]-D[u[x,t],{x,1}];
with the initial conditions:
...
- 1
0
votes
1
answer
35
views
Using ComplexPlot Command [closed]
I have been trying to make my function below work but it keeps giving a blank output,
Please help.
...
0
votes
0
answers
19
views
Conversion between Special functions
I want to convert a hypergeometric 2F1 function directly to a Chebyshev T or U function. Is Mathematica able to do the conversion? Theoretically it is possible (2F1 to JacobiP, then to Chebyshev T or ...
5
votes
2
answers
192
views
Why does polygon2FilledCurve not work here?
From my previous thread where @Alexey Popkov proposed polygon2FilledCurve to remove the outline when exporting to PDF. Now I'm trying to apply that to this but it ...
- 2,230
0
votes
0
answers
24
views
Simplifying/Approximating Hypergeometric Function
I have been working with Closed-form Hypergeometric function. Is there any possibility to simplify this function with multiple variables? Even if the approximation would be great.
...
- 23
2
votes
1
answer
81
views
How to set Frameticks properly?
I want to do a MatrixPlot and set the ticks to be from $-1$ to $1$ for both axes. Here in this (post Specify and rename ticks in FrameTicks) it is said FrameTicks work in this way
...
- 303
0
votes
1
answer
70
views
Why is my integral with the error function not being evaluated?
I'm new to Wolfram Mathematica and I was trying to evaluate this integral in particular:
$$\int_{0}^{x}\frac{e^t \operatorname{erf}(\sqrt{t})\sqrt{\pi t}+1}{\sqrt{\pi t x -\pi t^2}}\mathrm dt$$
The ...
4
votes
1
answer
44
views
Why does outline' color looks lighter? [closed]
I have been spending one hour but couldn't figure out this. Why aren't the color of outlines around the markers same with the lines'colors (it loosk lighter)? How can I make them be same?
...
- 2,230
2
votes
1
answer
57
views
Line integral around singular point (Residue theorem)
We have function $\frac{1}{x-\frac{i}{2}}$ which has one singular point $x=\frac{i}{2}$ so if we integrate around it we get by Residue theorem $2 \pi i$.
...
- 2,635
4
votes
2
answers
107
views
Plot with NDSolve for a range of initial values
I have a differential equation system as follow:
...
- 55
2
votes
0
answers
114
views
Why Mathematica 13.1 shuts down completely when printing to console but not to the notebook?
reported to WRI. ID [CASE:4950759]
I just found a very serious problem in V 13.1. Hoping someone will have a workaround.
I am able to reproduce this each time. V 13.1 on windows 10 pro. All from ...
- 110k
4
votes
0
answers
63
views
What are some basic references for learning "box language" and further mathematica language customization techniques? [duplicate]
I'd like to be able to understand and write mathematica code that is able to customize in some way the output of mathematica in notebooks, for example. I believe I need to learn the so called ...
- 41
1
vote
1
answer
38
views
Getting error message "The minimal damping factor of 1/10000 has been reached"
As a very beginner into Mathematica, I encounter error message as shown below when I am solving the system of three second order ODEs numerically using ...
- 117