2
votes
0answers
48 views

Custom graph distribution

I am working with random graphs a lot. It's quite easy to describe random graph using, adjacency matrix or just a list of edges. However I am thinking that I might benefit from describing random ...
1
vote
2answers
99 views

How to show system busy during Dynamic with SynchronousUpdating -> False?

For long running evaluations in Dynamic it is recommended that SynchronousUpdating -> False be used to prevent time-out. ...
4
votes
2answers
1k views

How to draw confidence ellipse from a covariance matrix?

I am studying a two-dimensional dataset, whose mean vector and covariance matrix are the following: ...
0
votes
0answers
104 views

Volume by NIntegrate gives zero

I want to Integrate the following expressions for different p < n and 2 < n with p and n both natural numbers: ...
0
votes
1answer
94 views

solving quadratic and linear congruences with different modulus

We are able to solve the quadratic congruences $C^2 + Q^4 - 2\equiv mod 3072$ and $C - Q^2 - 2046\equiv mod 3072$ by entering ...
-1
votes
1answer
95 views

How to make sure input is an ODE

I'm having trouble wrapping my head around why this isn't an ordinary differential equation. ...
0
votes
1answer
89 views

Why does my function return an expression rather than a number? [closed]

I feel like I'm going insane. I have a function $f(x)=e^{-x^2}$ which I need to evaluate using forward, backward and central first order finite differences with intervals ...
10
votes
2answers
221 views

Comparing natural language strings

I have a large spreadsheet with thousands of rows/columns of text. Some are saying essentially the same thing but in different ways. When you enter a natural language question Wolfram Alpha makes a ...
0
votes
2answers
111 views

Control legend size when autoLegend is used with LinTicks [closed]

It looks simple, but I'm been trying to solve this issue for days, but no luck yet. So, here I used LinTicks, as customized option and another graphic option. Here ...
0
votes
1answer
89 views

usage of random numbers in recursive loop

I am trying to evalute two functions using iterative process as below ...
2
votes
1answer
142 views

how to calculate the covariance of sample central moments

$\bar{x}= \sum_{i=1} ^{n} \frac{1}{n}x_{i}$ $m_1=\sum _{i=1} ^{n} \frac{1}{n} (x_{i}-\bar{x})$ $m_2=\sum _{i=1} ^{n} \frac{1}{n} (x_{i}-\bar{x})^2 $ $m_3=\sum _{i=1} ^{n} ...
0
votes
1answer
251 views

How To Use D[ ] to Define a System of PDEs

We have two variables $u_{1}$ and $u_{2}$ which are functions of $x,t$. That is, $u_{1}=u_{1}(x,t)$ and $u_{2}=u_{2}(x,t)$. Consider the the system of partial differential equations $$\frac{\partial ...
1
vote
1answer
42 views

Out labels looks strange after turning on magnification

As everything in Mathematica looks too small to me, so I turned on magnification when I am working. It looks good on windows: However, the Out tag is dislocated ...
2
votes
0answers
52 views

Import names into notebook namespace [duplicate]

I have function that at some point has list of strings (e.g. {"apple","pear"}) and I want to declare (initialize) those variables in notebook namespace to default ...
4
votes
1answer
159 views

Arrowheads in VectorStyle and StreamStyle doesn't work properly in VectorPlot and StreamPlot, respectively. A bug?

I'm using Mathematica 10.0.2 for Mac. Arrowheads given in VectorStyle for VectorPlot ...
6
votes
1answer
125 views

Graphics3D and Bit Depth of Rendering

A year or so ago, I sent this question to WRI (nb- a former employer of mine) and, as happens with bug-reports-that-arent-bug-reports, it was swallowed into the black hole that is Chambanna. So- I ...
1
vote
1answer
102 views

Finding adjacency matrix of a Mathematica's in-built graph? [closed]

I want to get the adjacency matrix of an in-built graph, say the dodecahedral graph. Naively using AdjacencyMatrix[Dodecahedral] doesn't give it to me. Any ...
4
votes
0answers
138 views

Possible Mathematica Bug? Blank Screen

I'm a student using Mathematica on a 2012 macbook pro with OS X Yosemite. Mathematica was running fine on my computer for a long time - one day, seemingly randomly, a blank screen started appearing ...
1
vote
0answers
40 views

Does “FiniteRingData” or something like that exists?

I want to find a function like FiniteGroupData but for finite rings. Does something like that exists?
2
votes
4answers
129 views

Pairs of data to Classify[]

Suppose I had the following data a={1,2,3,4,5} How would I turn this into b={{1,2,3}->4,{2,3,4}->5} That is, ...
1
vote
1answer
2k views

Add assumptions to Solve command

I want Mathematica to solve the following by assuming the part within the Log function, which is ...
5
votes
2answers
137 views

How can I run a list of Tasks serially?

I have a list of ScheduledTask's to run in sequence one at a time. How can I set these to run in order so that the next one starts automatically after the previous one finishes?
3
votes
0answers
60 views

Why does the debugger not stop when a message is generated?

I am on version 10.1. I have enabled the debugger and I have checked the box in front of "Break at Messages" in the Debugger Tools Window. However most the time the debugger does not stop when a ...
19
votes
1answer
721 views

Difference between Fitting Algorithms

I am new to Mathematica, and I don´t quite understand, what the difference between the fitting algorithms Fit, FindFit, ...
8
votes
1answer
895 views

Animated Wave propagation using split operator method

Here is the state of the art: By solving the time-dependent Schrödinger equation, one obtains that the propagated wave function after time step $\Delta t$ can be calculated by applying the ...
2
votes
1answer
128 views

Package editor interface

Is there a way to get rid of the unused space on the left of the package editor? What is it's purpose if I configured Mathematica to not show In and ...
1
vote
1answer
233 views

Plot a numerical integration as a function of a variable

Suppose we have a function that is hard to evaluate analytically but a numerical estimate suffices. For example consider the $f(x,\Lambda) = \Lambda\cdot \sin(x)$ where $\Lambda$ is some parameter I ...
7
votes
7answers
454 views

Generate a list

Given the list o = {xmin, xmax, ymin, ymax}; how can I generate the following list? ...
2
votes
2answers
136 views

How to speed up a system simulation?

I need to simulate a series of nonlinear (and linear) with thousands of state variables. Here is a simple linear example ...
4
votes
3answers
196 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
262 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
361 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
228 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
75 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
486 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
186 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
755 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
136 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
90 views

Constants from differential equations

I have a problem, I've solved 2 diff equations and I have: ...
4
votes
2answers
132 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
266 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
213 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
250 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
85 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
77 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
172 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: ...

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