0
votes
1answer
3 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? ...
0
votes
0answers
4 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 ...
3
votes
1answer
12 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 ...
0
votes
1answer
25 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
32 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
23 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 ...
0
votes
0answers
13 views

Intagrate over not explicitly given function

I would like to solve system of equations like this: 1) $f(x_{c},w,c,\lambda)=0$ --- from which I can implicitly find the value of $x_{c}=\gamma(c)$, knowing all other variables, plus number of ...
-1
votes
1answer
48 views

Why does Mathematica “sleep” when I don't work at computer?

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

StringLength function

allWeatherStations = WeatherData[]; fullformStations = FullForm /@ allWeatherStations; Tally[StringLength /@ fullformStations[[All, 1, 2]]]. This code not working. ...
0
votes
2answers
35 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
30 views

How can I combine two plots?

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

Dealing Repeated pattern in StringReplace

A problem about StringReplace When I'm running into this problem possible [bug] ...
1
vote
1answer
37 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
41 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
2answers
82 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
67 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 ...
1
vote
0answers
28 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
27 views

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

I wish to plot two sets of data on the same graph (two separate lines). However, everytime I put in the data, it acknowledges everything as strictly being an x ...
2
votes
1answer
50 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
15 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
36 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
23 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 ...
3
votes
3answers
90 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
71 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
35 views

Question on ClusteringComponents

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 ...
0
votes
3answers
59 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
37 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
55 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
42 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
102 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
23 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
62 views

Manipulate with plot and images

I have the following code: ...
0
votes
0answers
27 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
50 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. ...
0
votes
0answers
52 views

Matrix iteration failing after second step

I am calculating 11x6 matrix using different logics as in below code. Problem is in Do loop in below code where I have two different criteria to update matrix "fd". I am expecting logic in IF which ...
1
vote
0answers
46 views

Plot a data of four dimension

I have a confusion recently about the visualization of data.the data you can get there enter link description here.The construction of data is four dimension,like as {x,y,z,color},this is my current ...
0
votes
1answer
30 views

More than one graphic in Graphics command [on hold]

another question regarding plotting. I'm sorry, but somehow it is superhard for me to use these. I have a Graphics plot and I want to add a Point to it. A circle is already working. But everything ...
0
votes
1answer
67 views

Arbitrary hollow cylinders in mathematica 9

I'm having trouble displaying a hollow cylinder in Mathematica 9. A hollow cylinder looks like this: I tried to use RevolutionPlot3D with a step function. It ...
1
vote
1answer
45 views

In WolframAlpha, how can I make a Scatter Plot without connecting points? [on hold]

How do I plot a list of points without connecting the dots in WolframAlpha? I tried, for example, ...
1
vote
3answers
63 views

NDSolve parametric plot

Here is my code. s = NDSolve[{f'''[x] + f[x]*f''[x] == 0, f[0] == A, f'[0] == 0, f'[10] == 1}, f, x] I want to plot f''[0] ...
1
vote
1answer
49 views

Numerical solution of IVP for linear ODE with variable coefficient runs wild soon

A friend of mine showed me this initial value problem (IVP) for a linear ordinary differential equation (ODE) with variable coefficient: $$y''(x)=\left(x^2-1\right) y(x)$$$$y(0)=1$$$$y'(0)=0$$ Seems ...
0
votes
0answers
58 views

How to clear Mathematica's storage after a large computation? [on hold]

I've done some surfing and haven't found a solution to my problem... hopefully it is a simple one! Here is the problem. I have a Monte Carlo module that is stepping/tracking particles in a ...
1
vote
1answer
65 views

White Edges Around Graphics Elements

Using the following code, I am able to generate a grayscale Voronoi diagram: ...
0
votes
1answer
36 views

Replace element of matrix based on rule which invloves other element of same matrix

I am trying to replace 1s row of matrix d iteratively from right by multiplying last element in 1st row with (1-int*dt) to generate 2nd last element. The replacement continues till I reach the 1st ...
0
votes
2answers
52 views

Force Mathmatica to simplify an ArcTan[]?

I understand that there are many solutions that will produce the same arctangent, nevertheless I really need a simplification: ...
2
votes
1answer
72 views

Output an Expression in terms of GoldenRatio

Sorry if this is a dumb question (I'm new). I swear I searched and read forums first! I'm trying to rewrite expressions in terms of the Golden Ratio. For example, I know ...

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