All Questions
84,309
questions
1
vote
1
answer
61
views
Plotting mass spectrum of states
How can I obtain the following plot via Mathematica? I have my own data but I couldn't have obtained the plot. Thank you for your help
2
votes
3
answers
83
views
Solve and equation containing $\sinh$ and $\cosh$
I want to know how I can solve this or plot a versus b ?
Solve[ Sqrt[a] Cosh[1.2 Log[1.65 Sqrt[1/a]]] == Sqrt[-b] Sinh[1.2 Log[1.65 Sqrt[-(1/b)]]], b]
Thanks
- 133
2
votes
2
answers
270
views
How do I implement convolution integrals symbolically (not numerically)? [closed]
I'm working to symbolically solve convolution integrals i.e., using symbolic equations and not numerical methods of integration. The general form of the convolution I'm working to solve is as follows:
...
- 23
3
votes
2
answers
98
views
Unexpected behaviour of Condition with Cases/MatchQ?
When using the unsorted version of Complement in this question I met the following unexpected result,
...
- 31
3
votes
2
answers
57
views
How do I integrate this piecewise function with Mathematica?
I came across the question of what percent of numbers from 0 to 1 have a logerithm whose floor is even. What I did was I made a piecewise function: ...
2
votes
3
answers
103
views
Infinite Integral involving a Bessel function
I have trouble evaluating the following numerical integral,
$$
\int_{0}^{\infty} d k^{(yz)} \, k^{(yz)} J_{0} \left(d^{(yz)} k^{(yz)} \right) \frac{e^{-i d_x \sqrt{k_R^2 + {k^{(yz)}}^{2} }}}{ \sqrt{...
- 83
2
votes
3
answers
102
views
Divide string into a sublist of sentence with the maximum number of character
Context:
I have a long article (on Wordpress). And I'm using Google Translate API (v2) to translate this article. This article has about 300 000 characters.
However, due to the limit of Google ...
- 1,641
3
votes
1
answer
41
views
Why doesn't ListPointPlot3D plot a Table's output that iterates over three variables? [closed]
Why does ListPointPlot3D accept tables with 3 outputs and 2 variables such as:
...
- 31
9
votes
0
answers
116
views
Reduce: Var is not a valid variable
Bug introduced in 12.3 or earlier and persisting through 13.0.1 or later
I am trying to integrate the following but it returns a Reduce::ivar warning message.
...
- 1,123
0
votes
1
answer
104
views
Small question about the output form of the derivative
I have an expression:
D[D[Subscript[T, 1][x[t], y[t], x'[t]] + Subscript[T, 2][x[t], y[t], y'[t]], x'[t]], t]
The result is:
$y'(t) T_1{}^{(0,1,1)}\left(x(t),y(t),...
- 1,721
1
vote
0
answers
93
views
Mathematica can not interpret parentheses correctly [closed]
I want to sum up four terms but Mathematica does not interpret the parentheses correctly. In the picture, in second line there is only one term that starts with 1/12...
- 11
0
votes
0
answers
63
views
Problem with DSolve
I'm trying to solve a system of equations with DSolve, but Mathematica is neither giving any output nor showing any error. However, if I solve this system with <...
- 87
2
votes
2
answers
123
views
Solve singular fourth order ODE
I am interested in solving the following differential equation :
$$
\left(\frac{300 i}{r^{5}}-\frac{3}{r^{4}}\right) \psi(r)+\left(-\frac{45}{r^{6}}+\frac{3}{r^{3}}\right) \psi^{\prime}(r)+\left(\frac{...
- 345
3
votes
2
answers
132
views
FunctionPeriod for functions defined in a Piecewise manner
To create a minimal example, consider a piecewise function:
...
- 16.2k
2
votes
1
answer
119
views
How to give a property to a list of functions?
For example, I have defined a bunch of binary functions Sum1, Sum2, Prod1, ...
- 123
0
votes
0
answers
50
views
Minimum of a function that depends on several variables
I have a function,
$$A=\sum_{m}mx$$
provided
$$x=\frac{2(y1+iz)}{2t1-\left|\frac{t2}{iy2}+z\right|}$$
Here $$y1,z,t1,t2,y2$$ all are varying. But $x$ needs to be in the limit of $-1$ and $0$. Is there ...
- 1,163
0
votes
0
answers
45
views
Function aborts when inside manipulate
I have a function that completes without problems, as shown here.
VisualizeRx[textimage, "test", 1, 0, 0, "WriteFiles" -> False];
But when ...
- 1,857
8
votes
1
answer
104
views
How to get a membership condition for RegionBoundary using RegionMember
This is my first question on this forum, but by no means my first problem with Mathematica (which I've been using daily for years).
Consider
...
2
votes
0
answers
58
views
In an element of a matrix, can I refer in an element to its own row or column? [closed]
In an expression inside the matrix, can I obtain the indices of the element where this expression is located? Also, can I refer to other elements of that same matrix, like in spreadsheets?
- 2,751
0
votes
1
answer
117
views
How to solve 2D Heat equation on rectangle with NDSolve?
I am trying to solve the 2D heat equation $$\Delta u =u_t$$ with Dirichlet boundary conditions on the rectangle $(0,a)\times (0,b)$ and with initial condition $u(x,y,0)=g(x,y)$.
This is my code
...
- 125
5
votes
3
answers
267
views
Linear ODEs with NDSolve
I am trying to solve some first order linear odes. My code is below:
...
0
votes
1
answer
105
views
Heat Equation with Mobile Boundary
I am trying to use NDSolve to find the solution to a set of coupled diffEQs.
They represent 1d (radial) heat balance in a spherical shell.
The goal is to specify a heat flux into the base of the shell,...
- 123
3
votes
2
answers
293
views
Why do I get a different answer from Mathematica when calculating this integral?
I am curious and confused about the solution of this integral.
$$\int_{t}^{T}(1-e^{\alpha(s-T)})e^{\alpha(t-s)}ds$$
When I use Mathematica with this code
...
10
votes
1
answer
364
views
Can Mathematica read planar graphs with pc format?
We can download files about some special planar graphs at the following website, but their files are suffixed with pc.
http://users.cecs.anu.edu.au/~bdm/data/planegraphs.html
I don't know how to ...
- 763
1
vote
0
answers
63
views
Three nonlinearly coupled PDEs
I am new to Mathematica and I need it to solve a system of three nonlinearly coupled PDEs.
$\frac{n_1}{c_0} \frac{\partial E_1}{\partial t}+\frac{\partial E_1}{\partial x} = i\frac{\omega_1}{2n_1 c_0} ...
- 11
1
vote
0
answers
65
views
Possible bug: Wrong limit for `EllipticE`?
I encountered problem with computing limits of Elliptic functions E and F. For example,
...
- 535
0
votes
0
answers
59
views
Assigning code to a function makes it stop working
I know its a lot, but please bare with me I'll explain it step by step
I have a rare situation; as said in the question, I wrote a certain code, that runs perfectly by itself. However, since I need to ...
- 43
0
votes
0
answers
65
views
How to do this recursion relation in Mathematica effectively?
I have a function $h_{\Delta,l}(r,\eta)$ satisfying
\begin{equation}
h_{\Delta,l}(r,\eta)=\tilde{h}_{l}(r,\eta)+\sum_{k}\frac{c(k)}{\Delta-(1-l-k)}r^{k}h_{1-l+k,l+k}(r,\eta)
\end{equation}
where $k$ ...
- 51
10
votes
3
answers
360
views
Mapping a numerical array of numbers onto the surface of f(x,y) possible?
I'm considering mapping an error estimate matrix onto the surface of a function f(x,y) in the indicated range:
...
- 1,114
4
votes
1
answer
41
views
Timing Discontinuity with Replace[] Function
When constructing certain square matrices I noticed a sharp jump in the time required to build them. I've included code and a plot of time required to make the matrix vs dimensionality of the matrix. ...
- 187
2
votes
2
answers
57
views
ListLinePlot not showing one label in a cycle of points
I am using ListLinePlot to represent a closed circuit of points (forming a polyhedron). I am trying to label each node (point) of the cycle, but the node that is ...
- 1,057
2
votes
1
answer
33
views
Plot a region between two curves that is below another in $R^3$
I am trying to obtain a 3D plot of $z=x^2+2y^2$ that is bound by the region in the $z=0$ plane governed by the equations $y=x$ and $y=x^2$. Is it possible to do this with ...
- 33
5
votes
4
answers
572
views
Replacing large numbers
Imagine I have the following list
l = {{1,2,3},{4,10^(16),5}}
How do I efficiently replace the large number by a number (zero, for example). I can't seem to do it ...
- 4,228
4
votes
1
answer
248
views
Weird behavior of Derivative
I have noticed a weird behavior of the "Derivative" operator, and I would like to know to why is this happening and if it is intended, as I'm using this function quite a bit in my code and I ...
- 261
1
vote
0
answers
63
views
It is possible to call C functions with pointers as arguments in Mathematica?
Here is my goal: I want to call external library functions, written in C (not by me), in Mathematica.
I may have found a way to do it using LibraryLink by following this scheme:
First, for each ...
- 151
1
vote
3
answers
124
views
How can I get these decimals formatted properly?
It's nothing serious, but I was just wondering. I have a large number of floating point numbers which I write to a file. Mathematica writes each number with 17 decimal positions, which is way more ...
- 6,638
1
vote
1
answer
68
views
Series Expansion of EllipticNomeQ differs from older Mathematica Version
I am trying to follow the numerical approach on how to calculate EllipticE and EllipticK following this paper. In there on ...
- 4,437
1
vote
2
answers
41
views
Find min value of a complex Root function [closed]
Could someone tell me how to obtain the min value of this function when lambda is between 0 and 1:
...
- 11
8
votes
2
answers
111
views
Constructing a RootSum object changes existing internal syntax
Bug introduced in 9.0 or earlier and persisting through 13.0.1 or later
I noticed that initially valid syntax becomes invalid within nested RootSum objects. ...
- 2,929
1
vote
0
answers
33
views
How to authomatically extract info from error messages [duplicate]
I am using NDSolve to compute particles' trajectories.
Typically, I get an error of the type:
NDSolve::ndsz: At t == 0.11880535502829011`, step size is effectively zero; singularity or stiff system ...
- 259
1
vote
0
answers
44
views
How To Fit Heston Model To Stock Data Stochastic Volatility Model
The stochastic volatility model known as the Heston model can be expressed in Mathematica in the following way
https://reference.wolfram.com/language/example/HestonModel.html
Define the Ito process of ...
- 489
0
votes
0
answers
41
views
A way to tell mathematica to not alphabetically order second derivatives
I have a frame of vector fields $E_1 ,... ,E_6$ and it's convenient for me to write $E_1(f)$ as Dt[f,e1] where e1 is an ...
- 1
0
votes
0
answers
31
views
Graphing multiple functions on the same graph using AbsArgPlot, but the colour of the graphs keep coming up grey
I am trying to create a plot of the modulus of the eigenvalues of an associated matrix that is parameterised by sigma. When plotting a single eigenvalue using AbsArgPlot, the graph is coloured nicely ...
- 1
1
vote
2
answers
77
views
Change the Filling order
I want to this:
from this picture ,can find that "red" in front of "blue"
My code:
...
- 405
2
votes
1
answer
126
views
Stop Mathematica’s automatic indentation on existing notebooks
This question relates to Mathematica 12.3 (and possibly many other versions).
Mathematica's automatic indentation does not conform to my workflow. From the very old days of Mathematica 1.2, i.e. ...
- 2,512
1
vote
2
answers
146
views
Finding and plotting solutions of a complex function
I have a complex function given by
f1 = Sqrt[-16 x^4 - 16 y^4 - 16 z^4 - 32 I x^3 \[Pi] + 24 x^2 \[Pi]^2 + 8 I x \[Pi]^3 - \[Pi]^4]
When I plot the real part of ...
- 577
1
vote
0
answers
85
views
NDSolve for complex pde
My goal is to use NDSolve to solve the complex pde $F(z,t)$ with complex derivative $\partial_{z}=\frac{1}{2}(\partial_{x}-i \partial_{y}).$ The equation can be ...
- 11
2
votes
2
answers
126
views
PlotStyle for GridLines
I have:
Plot[x^2,{x, 0, 5},GridLines->{{3,4}},PlotRange->{5,30},PlotStyle->{Black,Dotted,Thickness[0.003]}]
How to make these two vertical lines in style ...
1
vote
0
answers
46
views
How to simplify a function imposing that it is equal to zero?
I have a function calculated by Mathematica given by
$F=\frac{1}{2r^3}sin[\theta]Y^{(1,0)}[\theta, \phi]((-4m+L(1+L)r)h0[t,r]+r(-2m+r)(-rh0^{(0,2)}[t,r]+2h1^{(1,0)}[t,r]+rh1^{(1,1)}[t,r]))$
and I want ...
0
votes
0
answers
56
views
Solving second order non-linear DE with boundary condition
I was trying to get some result from this equation but I can't find the solution. please see what is wrong with it??!! thanks
f, s are positive and k will be negative or positive.
...
- 133