All Questions
88,736
questions
3
votes
1
answer
52
views
Approximating exponential generating function (EGF) from values of generating function (OGF)
I have a function that can evaluate ordinary generating function, and need to construct an approximation to the exponential generating function by using a few calls to the ordinary generating function....
- 6,837
0
votes
0
answers
53
views
On a formula in Wolfram|Alpha [migrated]
I need to understand a formula for the Hypergeometric function $_3F_2(a,b,c;d,e;1)$
I searched and got the following from Wolfram alpha ( see:- second formula in https://functions.wolfram.com/...
- 97
0
votes
1
answer
70
views
Dsolve to find vector potential component's
I want to find the vector potential component's. I expand the Poisson’s equation in cylindrical coordinates which yields the three equations as in the picture. The equation along rho direction equal ...
- 1
3
votes
3
answers
112
views
Plot the graph of an integral
If I have a system of differential equations, I solve it and save the result in Sol:
...
- 33
2
votes
1
answer
145
views
Analytical Solution in Generalized Heat Equation
Given the following problem
$$u_{t}-\frac{v}{2}\cdot u_{xx}+\frac{v}{2}\cdot x^2 \cdot u(x)=0 $$
$$u(x,0)=f(x)$$
Where $ f(x)=y_1(x)+0.2y_4(x)+0.01y_6 (x) $
$y_n$ are the Eigenfunctions that defined ...
5
votes
2
answers
152
views
Sorting a list by a single particular element in a specified order
I have a list of lists -- a list of sublists -- that I wish to sort in a specified order. The following function, sortBy2ndElement, sorts a list of lists (...
- 9,747
2
votes
4
answers
404
views
How can I properly plot this region, with some filling too?
I have to plot this region:
$$A = \{(x, y)\in [0, 2]\times [0, 1]; x+y \leq 2\}$$
Here is what I did:
...
- 217
3
votes
0
answers
73
views
Compiling a function that uses MapThread
I'm looking for tips on quickly applying the following update to $B$ pairs of $(w_i,x_i)$
$$\text{step}(w_i,x_i)=w_i-a x_i \langle w_i, x_i \rangle$$
Below is a readable but very slow version ...
- 6,837
2
votes
4
answers
95
views
Splitting list into sublists based off string value [duplicate]
I'm new to Mathematica so please bare with me!
I wish to split an imported data list off of {x,y} values based off the y value, and then sum the corresponding parts.
An example of the imported list:
<...
- 153
0
votes
2
answers
62
views
One-way "cross" of function between two matrices
I'm trying to create a sort of one way "cross" of a function between two matrices, such that every pair in one matrix is mapped to every pair in the other, but not the other way around; for ...
- 101
1
vote
0
answers
32
views
Hold around SetDelayed with Graphics [duplicate]
Minimum Working Example
I've defined my own plot function, which does a lot of stuff to the inputs before passing it into the Graphics function. Because of that, I'...
- 428
0
votes
0
answers
39
views
Non-minimal coupling ξ , Minkowski false vacuum decay case (shooting method) (An update to the previous question)
I asked a few days ago this question:
Non-minimal coupling ξ - numerical bounce solutions (shooting method, false vacuum decay)
Alex Trounev helped me improve my code building based on this paper (...
0
votes
0
answers
18
views
Unknown Cell Collapse Type
Going through a notebook someone else put together, there are segments where a cell is mostly collapsed - you can see it is a code cell but not the code inside, but you can still evaluate the cell (...
- 105
5
votes
2
answers
86
views
Bug of ChoiceDialog
I am using Mathematica 13.1 on Windows 11.
I have the following bug with ChoiceDialog:
...
- 5,112
0
votes
0
answers
23
views
Building the documentation index in the cloud
How do I generate a persistent documentation search index in the Wolfram Cloud? Unlike in a local Mathematica installation, the
...
- 1
0
votes
0
answers
35
views
Tracing the phases (i.e. the minima) of a potential
Is there a Mathematica package to trace the minima of a potential as a function of some parameter, returning its phase structure?
Working with particle physics models (in the context of cosmology and ...
- 1
3
votes
4
answers
152
views
Cannot Draw a Composite Piecewise Function
I have defined two functions: g, which is a piecewise function, and h, which is the composition of g.
...
- 31
3
votes
1
answer
43
views
DSolve output displays different from actual output after using locator in Manipulate
V 13.2.1 on windows 10
If you look at this
it does look bizzar, right? The same variable sol is different from what it should be above it.
But the above ONLY ...
- 127k
0
votes
0
answers
34
views
Retrieving the documentation search ranking in Mathematica
I want to write a function that takes a search term and returns a list of built-in symbol suggestions.
The add-on function DocumentationSearch`SearchDocumentation ...
- 1
0
votes
1
answer
47
views
The shortcuts for typing subscript is valid
I installed the Mathematica 13.2 in my new computer， everything worked well excepted that the shortcuts for typing the subscripts "ctrl+ _" doesn't work. I tested that the "ctrl" ...
- 129
3
votes
3
answers
224
views
Intersection points of two-variable polynomials
Let $h$ and $g$ designate two multivariable polynomials:
$$\!\!h(x,y)=-96\! \left(32 x^2\!+\!8 x (3\!-\!8 y)\!+\!40 y^2-28 y+5\right) \left(10 x^2+x (4 y-2)+\quad\quad\quad\\ \quad\quad+(1-2 y)^2\...
- 159
2
votes
0
answers
34
views
Using "ToNumberField" as opposed to equations over the integers
Let D>1 be a square-free rational integer, and write \Q for the rationals. I am trying to determine the (non-)membership of ...
- 121
0
votes
0
answers
45
views
How to solve a fourth-order coupled system?
I would like to solve the following differential equations by NDSolve
Constants
...
- 117
0
votes
0
answers
54
views
The error estimates of the implicit Euler method in the book have different results [duplicate]
I use DSolve and NDSolve to solve a set of differential equations respectively, where NDSolve specifies an implicit Euler method, and subtract the results of both solutions to obtain the truncation ...
- 53
0
votes
1
answer
81
views
How to start another notebook calculation when one notebook is running?
If your first notebook is running and needs a long time to finish, but you still need Mathematica to do other calculation in another notebook.
The second notebook will not start until the first ...
- 65
5
votes
1
answer
207
views
Inaccuracy for FEM for 3D Heat Equation
I'm simulating the heat transfer within a cylindrical rod, with external heating from its sides.
...
- 103
0
votes
1
answer
58
views
Trajectories Missing From Phase Plane
I am attempting to graph trajectories for the system of equations (with independent variable t) given by
x'=5x-3y-2
y'=4x-3y-1
in the phase plane. For some reason, I can only graph trajectories for ...
- 5,211
3
votes
1
answer
40
views
Strange output of NIntegrate when constraining the precision with $Pre
One can constrain the precision of NIntegrate by setting PrecisionGoal:
...
- 2,754
2
votes
1
answer
52
views
Moment problem for a discrete probability distribution
Is there an elegant way to use Mathematica to find entries of a discrete probability distribution $\{p_i\}$ by using a finite number of calls to $m(t)=\sum_i p_i^t$?
There's a wikipedia article on ...
- 6,837
0
votes
0
answers
34
views
How to zoom, pan and otherwise visualize a huge graph?
I have a complicated tree I'd like to zoom in and investigate. It's quite dense and large.
Here's a simple way to reproduce the problem (my graph has 30K elements) but the 1K elements of this graph ...
- 2,369
1
vote
1
answer
59
views
Extract complex lists
I ask for the first time here.
I am not good at English , so I don't know that whether I can well tell you my question.
I want to create a model in which insects carry pollen from plants.
First, I ...
- 11
3
votes
1
answer
137
views
On the solution of systems equations with exact coefficients
It all starts with the following system of equations that I can't solve by hand:
...
- 4,402
1
vote
1
answer
47
views
Plot with manipulate
I want to use appropriately use the Manipulate command in conjunction with Plot, to construct animated graphics for the evolution of the solution. I have tried but i could not succed to solve it
$f(x)=...
3
votes
2
answers
100
views
Update Random Each Repetition of Animate
I found a solution that's not what I wanted but it will suffice
Thanks - Larry
...
- 31
2
votes
2
answers
82
views
Place frame in the correct position
I am plotting different waves (computed numerically and analytically) and, for that, I have used the following code:
...
- 21
4
votes
1
answer
96
views
How to find the common eigenvectors of these commuting matrices?
Given matrices P and Q defined as
P = {{x - I y, z}, {z, x + I y}}; Q = {{0, 1}, {1, 0}};
...
- 387
2
votes
0
answers
39
views
DSolve bvlim error due to Boundary condition
I am solving an Ode using Mathematica:
$$-p\alpha x^{p-1}=m\ddot{x},\quad x(0)=x_0,\quad x'(0)=x''(0)=0,\quad x(t_1)=0.$$
And I have $p\alpha>0$, all $x$ and $t$ are positive. I want to figure out $...
- 31
2
votes
1
answer
75
views
Background color depending on external function value on the same plot
I would like to plot a two dimensional list (ListPLot [{x, y[x]}]) where the background color is changing with x value according to the value assumend by an external function f[x]. Thank you.
Sorry, I ...
5
votes
1
answer
110
views
Mesh `Cylinder[{{0,0,0},{0,0,1}},1]` with inner boundary `x=y=0`
In a meshed cylinder Cylinder[{{0,0,0},{0,0,1}},1] I need to specify DirichletConditions along ...
- 42.9k
0
votes
0
answers
42
views
Statistics Clarification [closed]
I'm learning pretty basic statistical concepts, and want to clarify that my understanding is correct. I created a drawing to visualize what I think is correct, and I need to know if this is right or ...
5
votes
1
answer
100
views
Minimizing computational time for a quantum walk problem
Any suggestions as to how to speed up the computational time for this quantum walk problem which is coded using a normalized SparseArray coin operator as follows:
...
- 3,128
0
votes
3
answers
108
views
Plotting Average Positions of 2D Random Walk
I need to generate a plot that shows the averaged position at n steps of 1000 different random walks that are each 1000 steps long. So far I am using ...
- 1
1
vote
0
answers
50
views
ContourPlot fails to plot a simple triginometric function squared [closed]
The two plots should be exactly the same in the following. However, the one squared gives nothing. I tried MaxRecursion, ...
- 4,564
2
votes
2
answers
124
views
Entering matrices interactively
I am looking for a way to enter an m*n matrix interactively using a dialog or a Graphical User Interface(GUI). Further, I would like to use this matrix later for ...
0
votes
0
answers
62
views
Why does ListPlot not plot all the points? [closed]
I have a list of {x,y} values that I want to ListPlot. Here is a shortened example:
...
- 199
2
votes
1
answer
70
views
List of parameters as argument for Manipulate
Let's say, that we have a list of parameters, that we want to use in manipulate, like so:
parameters={{a,0,5},{b,-1,5}};
Of corse you could manually copy and paste ...
- 511
3
votes
1
answer
74
views
Assume asymptotic value in a limit?
Is it possible to give Mathematica a limit about's function at infinity?
For example I would like to
...
- 438
1
vote
0
answers
53
views
Fractional Differential Equation
I am facing the following problem.
If u[x_,t_]=t+y[t]x,
Then,
D[u[x,t],t]
Gives us
1+xy'[t].
But if I use the command for Fractional Derivative like
FractionalD [u[x,t],{t,a}], then Mathematica print ...
1
vote
0
answers
49
views
NDSolve stops solving past a certain time
This is a continuation of the post I've made Unable to solve Delay PDEs Error in Boussinesq Approximation. I apologise if I shouldn't have posted a seperate question for this but I think that the ...
- 103
6
votes
1
answer
152
views
Round ends for dashes [closed]
I made use of
Plot[Sin[x], {x, 0, 2 \[Pi]},PlotStyle -> Directive[AbsoluteDashing[10, 2],AbsoluteThickness[3], CapForm[Round]]]
Then I can have
It drives me ...
- 479