4
votes
3answers
198 views

Best way to represent a complex time schedule?

What would be the best way to represent a complex schedule in Mathematica ? For example a representation of the plain words schedule: "From Monday to Friday, from 8 am to 12pm and from 1pm to 4pm", ...
7
votes
0answers
269 views

How to generate a random flow graph?

A flow graph is a rooted directed graph that the root reaches all other vertices. I need to generate a random flow graph in Mathematica. My idea is to use ...
1
vote
2answers
55 views

Subsituting expressions for expressions

I'm trying to define functions using other functions, like so: f[a_, b_] := a/b; a[c_] := c; b[d_] := d; Now what I want to be able to do is two things: ...
0
votes
1answer
398 views

How can I use nonlinear model fit with multiple variables? [closed]

I have a data set with four entries. the first three entries correspond to variables in the fit x,y, & z. The fourth entry corresponds to the function value. I am trying to fit this data to a rate ...
3
votes
0answers
78 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 ...
2
votes
1answer
234 views

How do I download and export data from many weather stations?

I tried this code, which downloads data from several weather stations. ...
-1
votes
1answer
76 views

Factor out certain terms using Modulus but Mathematica requires that the modulus be an integer [closed]

Mathematica demands that the modulus be an integer. How do I work my way around this?
5
votes
1answer
525 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
83 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 ...
1
vote
1answer
206 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. ...
21
votes
5answers
767 views

Removing a histogram's 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 ...
0
votes
1answer
143 views

Equation solving problem [closed]

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

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

I have the following mathematica expression: ...
1
vote
1answer
93 views

Constants from differential equations

I have a problem, I've solved 2 diff equations and I have: ...
4
votes
2answers
139 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? ...
4
votes
0answers
279 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 ...
7
votes
1answer
230 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 ...
-2
votes
1answer
273 views

How to generate normally distributed random number [closed]

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
86 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
79 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 ...
-3
votes
1answer
181 views

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

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

StringLength function [duplicate]

allWeatherStations = WeatherData[]; fullformStations = FullForm /@ allWeatherStations; Tally[StringLength /@ fullformStations[[All, 1, 2]]]. This code not working. ...
2
votes
3answers
722 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
86 views

How can I combine two plots? [closed]

I am interested in plooting x only from 0 to 1, and afterwards x^2, only from 1 to ... whatever ...
1
vote
1answer
117 views

Dealing Repeated pattern in StringReplace

A problem about StringReplace When I'm running into this problem possible [bug] ...
23
votes
2answers
606 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
100 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 ...
4
votes
3answers
360 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
170 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 ...
4
votes
0answers
118 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 ...
3
votes
2answers
195 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
27 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
143 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 ...
4
votes
3answers
301 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
99 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
46 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
151 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
48 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
42 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
45 views

Truncating a List of Subsets of Ordered Pairs

I have a set of pairs: ...
0
votes
2answers
78 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. ...
1
vote
4answers
164 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
36 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
110 views

Manipulate with plot and images

I have the following code: ...
1
vote
1answer
309 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 ...
1
vote
0answers
60 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
71 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 ...
2
votes
1answer
160 views

Plot a data of four dimension

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

More than one graphic in Graphics command [closed]

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
305 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 ...

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