0
votes
0answers
56 views

Error with ND Solve

I am new to Mathematica, and I am having some issues solving a homework problem of a differential equation. Here is the code: ...
0
votes
0answers
78 views

Calculating 15 coupled differential equations [on hold]

I have 15 coupled differential equations linear in time that need to be solved. Rewriting the equations in a matrix form, they can be expressed following as a single equation, $\frac{d ...
0
votes
0answers
45 views

How to find multiplication of all elements in a 3d matrix?

Here's my input. It's a 15x4 matrix of 3x3 matrices (In other words a 3d matrix): ...
2
votes
0answers
108 views

Intersecting RegionPlots

Does the Mathematica graphics system have any concept of intersecting regionplots? I've found about intersecting graphics but not regionplots so far. For example, if I want to show the intersection of ...
2
votes
1answer
99 views

Curl expression does not evaluate [closed]

I am using Mathematica 8 on OS X. I am trying to compute the cylindrical curl of a symbolic vector following Mathematica documentation. ...
2
votes
2answers
152 views

Can not generate graph using smooth kernel distribution

I am a newbie to Mathematica so this question might looks silly. I want to generate a smooth kernel distribution graph for this set of data. The data I uploaded has two columns, the first column is ...
-1
votes
0answers
73 views

Trouble summing over many indices [on hold]

I'm trying to solve a problem by using `Sum, but as I have many indices (14) in the summation, the running time is awful. My program looks like this: ...
0
votes
2answers
63 views

Adding ticks to PolarPlot [closed]

I want to add some number ticks to a unit circle in PolarPlot like the one attached, but how can I do it? ...
4
votes
2answers
174 views

Maximization in Mathematica using matrix and vector notation

I am trying to solve a simple maximization problem in Mathematica, using matrix and vector notation. ...
4
votes
1answer
103 views

How to analyze all the data in a directory

I am trying to import, analyze, and save all the .txt files in a specific directory. I can do this with a single .txt file using the following code: ...
1
vote
1answer
41 views

Calculations after NumberForm [duplicate]

As specified in documentation center the functions AccountingForm, NumberForm, etc. are useful only to display numbers in ...
0
votes
1answer
103 views

Integrate does not work on my expression

I am trying to integrate a simple equation. The code is as follows ...
1
vote
2answers
94 views

How can I speed up this code with 4 variables sum

I have to make a sum over 4 variables. My code is very very slow. I want to know how to speed up this code. This problem is related to but different from one previous problem. Any help or suggestion ...
6
votes
5answers
162 views

Nested list from a flat folder list

I have a list of folders and files in my current working directory as a result of a built-in function FileNames: FileNames["*", "", Infinity]]. It looks like this: ...
3
votes
1answer
108 views

Typesetting in Mathematica

Are there typesetting environments/boxes or something similar in Mathematica? I want to write some documentation for a notebook using text cells and I would like to have a brief description of my ...
3
votes
2answers
46 views

Syntax highlighting in text cells

I want to write some documentation for a notebook using text cells. Now, I can select parts of the text within such a text cell and set its style to "Input". This does change its font, but there is no ...
3
votes
1answer
43 views

Export followed by Import producing “0.e1” numbers

I had a large table of data that I exported, and then when it had completed, I exported it to a file. (Just in the form Export["filename.dat", data], no specified ...
-2
votes
0answers
40 views

How to assign values to constants inserted in a solution by DSolve [on hold]

I am trying to solve first order ODE with DSolve, but it didn't pan out. How can I solve for the inserted variable K[1]? Your ...
7
votes
1answer
126 views

Determining FinancialData for Countries

How do I determine the FinancialData for Australia. For instance the one for USA follows as: FinancialData["NYSE", "Members"] ...
3
votes
1answer
37 views

In NMinimize, how can I efficiently handle NIntegrate errors for non-integrable functions?

I am using NMinimize to find parameters that minimise the integral of a function in the least squares sense: ...
-4
votes
0answers
65 views

How to define this function in Mathematica? [closed]

Q set of rational, Q' set of irrational Determine $F+G$ , where $F(x) = x^2$ when $x \in Q$ and $-x^2$ when $x \in Q'$ $G(x)= {(2^{1/2},4),(7,0),(3,8)}$
2
votes
2answers
110 views

Show and hide various pieces of information in a Manipulate

I wanted to change the visibility of a function and its additional informations within a plot through the help of a checkbox, as shown in that post: Toggle visibility of elements in a plot But ...
0
votes
1answer
68 views

Integrate works but NIntegrate doesn't

I have a complicated integral function that I'm trying to evaluate, which will have to be done numerically. I wanted to try a simpler one first, one that has an analytic form, because I could check ...
0
votes
3answers
54 views

How to generate a list of outputs for function f(x,y) for a set of known (x,y) values [closed]

Say I want a list of outputs the function f(x,y)=x+y will give for x,y values of (1,5),(5,3),(0,2),(1,1),(2,6). How do I do that? I know this must be pretty straight forward. I just can't figure it ...
4
votes
0answers
92 views

Simplest identity that cannot be proved by FullSimplify [closed]

Apparently, FullSimplify is not able to prove all true identities, but usually it does pretty well when it comes to elementary functions. I'd like to know what are ...
1
vote
0answers
33 views

Formatting the output of SubstitutionSystem to create a Cantor set [closed]

I want to create a Cantor set using SubstitutionSystem, and plot it appropriately. This is the best I've been able to do so far: ...
5
votes
2answers
73 views

How to show the direction of highlighted path in graph

I am trying to show the direction of FindHamiltonianPath on the Graph. ...
5
votes
3answers
315 views

Finding all of the words containing certain letters

Is there a fast method to find all of the words containing the letters: {a, e, i, o, u, y}? I created an algorithm, but it takes more than 11 seconds to find all of ...
1
vote
0answers
46 views

Solving an ODE using shooting method [duplicate]

I have been trying to solve the following nonlinear ordinary differential equation: $$-\Phi''-\frac{3}{r}\Phi'+\Phi-\frac{3}{2}\Phi^{2}+\frac{\alpha}{2}\Phi^{3}=0$$ with boundary conditions ...
2
votes
1answer
47 views

Dynamic update of displayed quantities on a Plot within manipulate

I'll admit that I only skimmed some other threads about this. They seem rather complicated in contrast to my simple problem. I have two lines in space defined by a two-by-two coefficient matrix. I ...
3
votes
0answers
53 views

Method of characteristics, recursion formulas

I'm helping a friend out with a problem. He needs to plot out the solution to a water surge in a pipeline. I have all the parameters set and I've put the equations in Mathematica, but I can't get the ...
-1
votes
0answers
25 views

How can I sketch a Plot using direction field? [closed]

I can't plot a graph of first order initial value problem using direction field
3
votes
2answers
109 views

Plotting a simple graph with more than 1 variables

Here's what I did: Plot[(Q E^(-(x^2/(4 t))))/(2 Sqrt[π t]), {x, 0, 10}] I want only x to vary. But Mathematica is giving me a blank plot. It's very strange. I ...
3
votes
0answers
52 views

How to speed up a high dimensional numerical integration of Gaussian-form integrand

My integral has the following form: $$\int \sin(\theta) d\theta d\phi\left| \int d^3p_1 d^3p_2d^3p_3 \frac{f(p,\theta,\phi)}{g(p,\theta,\phi)}e^{-\frac{1}{2}(p^\mathrm{T} .A.p)}\right |^2,$$ where ...
12
votes
1answer
122 views

Form of citation for data via Wolfram Mathematica

What citation or reference should I adhere to if I'm using curated data obtained via Mathematica? I'm talking about data, or eg. plots thereof, obtained using functions such as SatelliteData, ...
9
votes
0answers
111 views

Memory usage of compiled function: C vs WVM

Why does generating an array in "C"-compiled function uses 50% more memory than doing same thing in "WVM"-compiled function? ...
2
votes
0answers
33 views

Solving a differential equation with a complex (independent) varible

I'm trying to plug in complex values in the numerical solutions of ODEs without success. For instance y[I] /. NDSolve[{y'[x] == 0, y[0] == 3}, y, {x, -10, 10}] ...
0
votes
1answer
29 views

Using Select function to select elements based on last element of nested list [closed]

Good morning, I have a list with each element containing a tuple and a single. It is of this form: ...
9
votes
1answer
84 views

How to partition a 2-D array properly?

Given that I have the following array lst = Array[Subscript[P, #1, #2] &, {5, 5}, {0, 0}] $ \left( \begin{array}{ccccc} P_{0,0} & P_{0,1} & P_{0,2} ...
5
votes
1answer
89 views

Vertex Order of Graph

Given a graph, I want to find the shortest distance between each pair of vertices: ...
6
votes
0answers
86 views

What is the best way to transfer arbitrary-precision reals using WSTP?

I'm developing a Mathematica package, inside of which there is a number-crunching function. It uses a list of arbitrary-precision numbers as input and it takes a lot of time to do its job. So I've ...
0
votes
0answers
73 views

Evaluating a derivative at a specific point [closed]

I'm quite new to Mathematica (and stackexchange) so I'm getting stuck on something simple. I have the expression $$ \phi_{n}(z,s)=q^n\left[-\frac{e^{-sb}z \left((1-q)^{\lfloor \gamma\rfloor} ...
0
votes
2answers
45 views

Custom multivariate discrete distribution [closed]

This is related to How to define an n-variate empirical distribution function probability for any n? and RandomVariate from 2-dimensional probability distribution but I don't think neither questions ...
0
votes
2answers
54 views

How to use the {{ lhs == rhs, ineqs }, … } form of Exclusions?

I am trying to make use of this option: To plot the principal portion of Tan: ...
1
vote
0answers
44 views

Plotting roots for a singular numerically-only integrable equation

In my problem I need to plot roots with respect to a parameter. But the condition for root is det(Function)=0. This function cannot be solved symbolically. So I need to put in a parameter value and ...
-2
votes
0answers
42 views
3
votes
2answers
94 views

Coloring image components according to their area

I have a rasterized image img that is created by this code: ...
4
votes
1answer
109 views

How can I temporarily suspend the Combinatorica package?

Sometimes after I load the Combinatorica package by entering Needs["Combinatorica`"], I need to use Mathematica for something like: ...
1
vote
0answers
29 views

Loading a notebook to a website

When I upload a Mathematica notebook to my website, when I click on the link, it opens, but as text, not a Mathematica notebook. At some sites, when I click on a Mathematica notebook, the notebook ...
4
votes
1answer
101 views

How can I make angle brackets function like lists?

Is there a way to make <a,b,c> behave like {a,b,c}, but remain displayed as ...

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