0
votes
0answers
6 views

How to speed up solution of system of recurrence equations

I was wondering how I can improve the speed on this method for solving a particular system of coupled recurrence equations. The system is $$ \begin{align*} &V(m)=\alpha + \beta V(m+1)+\beta ...
0
votes
0answers
11 views
0
votes
1answer
18 views

Factor out certain terms using Moduls but Mathematica requires that the modulus be an integer

Mathematica demands that the modulus be an integer. How do I work my way around this?
2
votes
0answers
39 views

How to plot the solution of a Partial Differential Equation?

My attempt. I need to solve numerically the Complex Ginzburg-Laudau Equation (CGLE): $$ \frac{\partial A}{\partial t}=\epsilon A-(1+i\beta)|A|^2A+(1+i\alpha)\nabla^2A $$ I'm using a uniform initial ...
0
votes
0answers
29 views

Difficulty solving an equation involving a couple of different powers

I have this semi-complicated equation to which I want to find an analytical solution for $\epsilon$. The equation is a s following: $$a^2 (2 b k \epsilon \sqrt{1 - \epsilon^2/b^2} - 2 c k ...
0
votes
1answer
26 views

How to properly use conditionals inside NDSolve

Currently I am working with Mathematica to learn the program, and I'm confused what exactly is wrong with this code. ...
4
votes
3answers
63 views

removing Histogram vertical edges

Let's say I have a Histogram: Histogram[RandomVariate[NormalDistribution[10, 2], 500]] How can I remove vertical lines inside the histogram and keep only the ...
-3
votes
0answers
42 views

Billiard in the square [on hold]

I have code for building the billiard in square. How I can draw it with changing the first point? ...
0
votes
1answer
54 views

Equation solving problem [on hold]

I have this code: ...
0
votes
0answers
44 views

How do I plot an expression in mathematica? [duplicate]

I have the following mathematica expression: ...
0
votes
0answers
19 views

Difference between DSolve and NDSolve [on hold]

What's the difference between DSolve and NDSolve? I know both can be used but I'm not sure of the exact difference.
0
votes
1answer
40 views

Constants from differential equations

I have a problem, I've solved 2 diff equations and I have: ...
-4
votes
1answer
29 views

Plotting various circles [on hold]

I want to plot various circles in the same graphic using the command Circle. I mean, something like: Does anyone has an idea?
1
vote
2answers
36 views

Using LeviCivitaTensor

I have 2 questions about using LeviCivitaTensor, based on the following session: The signs for the cross product seems to come out "opposite" of what I expected. Why is that? Did I miss anything? ...
2
votes
0answers
38 views

Help with Fourier analysis and filtering of an image

I am starting with the following image: For the curious, it is an STM scanned image of graphite. I am hoping to find some kind of periodic structure in the image related to the honeycomb structure ...
6
votes
1answer
83 views

Find and return the key with lowest value in association list

I am still new in Mathematica, and I need some help here. Suppose that I have an association ...
-1
votes
1answer
37 views

How to generate normally distributed random number [on hold]

I want to sample or return random number from a distribution which is normally distributed with mean of zero and standard deviation of 1. I am using RandomReal[NormalDistribution[0, 1]] I s this ...
2
votes
2answers
58 views

Arrangements (?) from permutations of rows in a triangle, is there a simpler way to program this?

I am generally confused about integer valued polynomials, and how to count them. Trying to learn the subject I started by listing permutations of the rows in a lower triangular table: $$\displaystyle ...
1
vote
1answer
27 views

Replace symbols in output without evaluation

I found the Wolfram example for ExpandNCM but I want a more human-readable output form. I want to evaluate ExpandNCM, for example with ...
-2
votes
1answer
79 views

Why does Mathematica “sleep” when I don't work at computer? [on hold]

I started using Mathematica few days ago. I'm running this code: ...
0
votes
0answers
42 views

StringLength function [duplicate]

allWeatherStations = WeatherData[]; fullformStations = FullForm /@ allWeatherStations; Tally[StringLength /@ fullformStations[[All, 1, 2]]]. This code not working. ...
1
vote
3answers
69 views

DSolve with assumptions

I'm new to mathematica and was wondering if someone could help me. I have a differential equation which is: $\frac{dy}{dx} = 1/2 y(1 - y)(a - y + a y)$ It has initial condition $y(0) = y0$ and ...
0
votes
1answer
40 views

How can I combine two plots? [on hold]

I am interested in plooting x only from 0 to 1, and afterwards x^2, only from 1 to ... whatever ...
0
votes
0answers
22 views

Dealing Repeated pattern in StringReplace

A problem about StringReplace When I'm running into this problem possible [bug] ...
10
votes
2answers
243 views

Better way to visualize cylinder puzzle solution

The above puzzle has been a recent source of amusement in my clique. I decided to provide a visualization to motivate solution (here): My code: ...
0
votes
2answers
49 views

Plotting vectors using derivatives

This question stems from a previous question I asked here: Multiple Integral of equation including dx prime? An equation describing a gravitational field of a cuboid is given as: $V(X,Y,Z) = -G\rho ...
1
vote
3answers
99 views

How could I transform the YYYYDDD date string/Integer to YYYYMMDD date string?

suppose I have lots of YYYYDDD date Integers which look like(for example): ...
0
votes
4answers
74 views

How to trim the zeros from the right of a list? [duplicate]

I need to remove the zeros from the right of an integer list up to the first non-zero element. Such as {0,1,0,0,2,0,0}->{0,1,0,0,2}. Padding zeros can be simply ...
3
votes
0answers
53 views

Why the flat f[x] is treated as ghostHead_[f[x]]?

While reading this answer I feel confused. If we do not care any specific detail of the original question, then ybeltukov's answer essentially makes use of the following fact ...
0
votes
1answer
41 views

Question about Plotting Two Sets of Data (repetitive, but previous question did not help me) [on hold]

EDIT: Sorry, I just realized I was using the Wolframalpha mode instead of pure Mathematica!! Sorry for troubling everyone!! Have a joyful and lovely day!!!! I wish to plot two sets of data on the ...
2
votes
1answer
69 views

Solve the “Cheryl's birthday” puzzle using mathematica

The "Cheryl's birthday" puzzle has been circulating around, the backstory is available via wikipedia. The puzzle itself is reproduced here: Albert and Bernard just became friends with Cheryl, and ...
0
votes
0answers
16 views

Unable to save a notebook as pdf

I have removed all the dynamic and manipulate cells. I can save short selections as pdf, but when I try to select the whole notebook, or use save as - pdf, the result is just one page, sometimes the ...
0
votes
1answer
38 views

How to import data from a .mat or a .txt file and manipulate dimensions

I'm new to Mathematica (I know very, very little - so I apologize if anything I say is absolutely wrong) - but I'm trying to upload a file from matlab and arrange it in matrix form. I have a .mat ...
0
votes
0answers
31 views

Multiple Integral of equation including dx prime?

I'm hoping someone can verify I've written this function properly since I'm a little new to Mathematica. What I'm attempting to do is code a function that describes a gravitational field of an ...
4
votes
3answers
99 views

How to fit parameters in a system of coupled differential equations

Problem description: I'm studying a chemical reaction that can be modeled by a system of coupled differential equations, and I want to use measured data to determine the parameters that appear in the ...
3
votes
2answers
74 views

How to use an expression for the argument to a function [duplicate]

I would like to define a function over a list of variables like f[a_,b_,c_]:=a+b+c However, when this list is big it makes uncomfortable to read. Can I somehow ...
1
vote
0answers
37 views

Question on ClusteringComponents [duplicate]

I am fairly new to Mathematica. I've been playing around with ClusteringComponents. Assume we are clustering points in the plane using k-means clustering and ...
1
vote
3answers
63 views

Absolute VectorPlot scaling

I'm trying to visualize the vector components of a rotation matrix with absolute vector lengths. VectorScale help states that When using an explicit sfun, ...
0
votes
0answers
38 views

How to invert the default order of polynomial? [duplicate]

By default, Mathematica outputs polynomials starting with smallest degree. How can I invert this?
0
votes
0answers
14 views

Possible bug of Exporting as HTMLFragment at Linux

This is the result of Mathematica 10.0.2 of Linux Version. There are two style inside one tag, and this fragment cannot be Imported as XML by Mathematica. This is the result of Mathematica 10.1 of ...
1
vote
1answer
22 views

Truncating a List of Subsets of Ordered Pairs

I have a set of pairs: ...
0
votes
0answers
23 views

Definition of function for integration [on hold]

I have this function: g33[p_] = Integrate[1/(a - b) (a μ2[-p/b] + μ1'[-p/b] - 2 a g2'[(-a p)/b] - (a + b) g4'[-p]), {p, -l/b, 0}] And I want to call it with ...
0
votes
2answers
57 views

Returning value if a point is in a region?

I'm writing a function so that if the user clicks on a certain region, a value is returned. The function takes in a condition list like the one below and a point. ...
0
votes
0answers
43 views

How can I make a plot of integer lattice? [on hold]

I want to make a plot of complex plane with dots representing visible lattice points. I want the result represented somehow like this: ...
1
vote
4answers
103 views

Manipulating List?

I have a huge list with 1000 elements. Manually entering and calculating SUM of probabilities it would take a few hours. Example: list = {1, 2, 3, 3, 4, 3} ...
1
vote
0answers
24 views

ConnectedComponents problem of syntactic structure

In Mathematica 10, ConnectedComponent computes the list of vertices belonging to strongly connected components. In the following simple example with a graph with no edges, the result is as follows: ...
1
vote
1answer
63 views

Manipulate with plot and images

I have the following code: ...
0
votes
0answers
29 views

Package for symbolic computation of christoffel symbols and parallel transports in Riemannian geometry, given the metric

I've no knowledge in mathematica (but I do in matlab), but I'd really appreciate if someone could mention what is/are the best and easy to learn mathematica package(s) for symbolic and numerical ...
0
votes
0answers
23 views

PeriodogramArray or PowerSpectralDensity?

could anyone explain what is the difference between PowerSpectralDensity[data,omega] and PeriodogramArray[data]? When I plot them (starting from the same set of data of course) I get two different ...
0
votes
0answers
51 views

I made my own equation, how do I know if it already exists? [on hold]

I made my own equation after playing around with some numbers. So I started to look for the equation to be sure I made it first. I googled and searched for it almost everywhere but couldn't find it. ...

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