25
votes
4answers
3k views

How to generate a random tree?

Is it possible to generate a random tree without explicitly constructing a random adjacency matrix that satisfies tree properties? How about a random directed tree? Edit: incredible answer by ...
36
votes
5answers
2k views

Can the banner in the Home Edition be removed?

The Mathematica Home Edition shows a banner at the top of every notebook: Is there a way to (permanently) get rid of it, without violating the EULA? Edit Yesterday, I sent this message to WRI ...
25
votes
3answers
1k views

Symbolic solution(s) to generalized Heat equation

Symbolic solution(s) to Heat equation? or more generally,(eventually) Green functions to known PDEs I am interested in variations of the heat equation: or more generally or even more generally ...
25
votes
3answers
1k views

Smooth Peter de Jong attractor

Today I was playing with Peter de Jong attractor. At the bottom of the page I've linked there are beautiful examples like: My attempts are not so great: It is around 10^5 points. For more than ...
22
votes
7answers
2k views

Is there a way to recreate the typical Red/Blue-Postereffect using Mathematica?

I think nearly all of us have at least once seen an image like this: So I wondered whether it is possible to recreate this effect using Mathematica because it seems like it wouldn't need that many ...
22
votes
2answers
1k views

What are some advanced uses for Block?

I read the answers to this question (What are the use cases for different scoping constructs?) and this one (Condition, Block, Module - which way is the most memory and computationally efficient?). ...
21
votes
3answers
2k views

Improve Plot3D resolution near max/mins

I have the following function $$V(r) = \sum_{i=1}^N 4 \epsilon_i \left(\frac{\sigma_i^{12}}{\|r-r_{0i}\|^{12}}-\frac{\sigma_i^6}{\|r-r_{0i}\|^6}\right)$$ which -for those interested- corresponds to ...
29
votes
1answer
928 views

Numerics with Mathematica

From time to time, I would like to use Mathematica purely numerically, e.g., plotting a function which is defined as an integral which cannot be solve analytically or a solution of a differential ...
27
votes
5answers
1k views

Tips on giving a lecture course using Mathematica

I've had a look at this question on giving presentations with Mathematica which is very useful on the technical side of setting up slideshows. However, my question is more about the integration of ...
20
votes
2answers
1k views

Weather Maps with Mathematica

I've been trying to set up a weather map with Mathematica similar to what NOAA publishes in their website. So far I've been successful to bring the data over and extend it across the whole picture ...
19
votes
4answers
1k views

How to calculate the volume of a convex hull?

Given a spatial curve represented by a parametric equation, is it possible in Mathematica 9 to calculate symbolically (or at least numerically) the volume of its convex hull?
21
votes
4answers
1k views

Time-series decomposition in Mathematica

I'm studying time-series in R with this book, and there is a nice command in R that creates decompositions. Inside Mathematica 9 the command can be executed as: ...
21
votes
1answer
542 views

A palette of accumulated expertise

I've been trying to put together a palette of useful functionality garnered from this site. There is useful stuff scattered all over the place, for example: Post an image Copy code Duplicate a ...
21
votes
3answers
1k views

Does every Symbol in Mathematica induce a monad?

From my question about types in Mathematica, I assume that every Symbol in Mathematica is a type if it appears as a Head of some ...
20
votes
3answers
1k views

How can I make a heatmap of a days in year?

I know Mathematica has a ListPlot for time series but does it have a function for visualizing a list of dates as a heat map like this: This idea is from D3, check it out here.
30
votes
4answers
820 views

How to make a stereogram in Mathematica?

Given a background and a pattern jpg files, is there a quick and easy way to produce a stereogram by using Mathematica? The following picture was produced from Photoshop, spent about half an hour. ...
21
votes
2answers
893 views

How to generate a picture like this?

How to generate a picture like this? I'd like the surface of the manifold to randomly distort.
17
votes
1answer
645 views

Calling Mathematica from Visual Studio - example

I am trying to set up a connection between Visual Studio 10 and Mathematica 8.0 on a Windows system. I found several sources of information on the Wolfram website, but I get entirely lost. Most of the ...
16
votes
3answers
867 views

3D view of a route shown on a map

You should have already seen such a thing, specially in documentaries about ancient life: the movement of a tribe is shown on an ancient map along a route with a dashed arrow. I want to do the same ...
15
votes
1answer
392 views

How to write documentation in Wolfram Style?

Rather than craft my own stylesheets for documentation, I'd like to emulate (copy? ape? borrow?) the Wolfram style. Here is a very small example (type this in the help-box, which you get by pressing ...
13
votes
1answer
339 views

How do I get a general form for n-th derivative of a function? [duplicate]

I tried the following but it basically returns unevaluated: ...
28
votes
2answers
2k views

Animating a Voronoi Diagram

edit: Excellent answers have been provided and I made an animation which is suitable for my use, however, all the examples rely on bitmap/rasterized data; is there a vector based approach? I would ...
27
votes
4answers
724 views

What is the natural way of using Dataset to get a FittedModel?

The new Dataset in Mathematica 10 is a great addition to the language, potentially reducing the convenience gap with R. Given this, I would like to understand what the equivalent simple or natural ...
26
votes
3answers
3k views

Understanding differences between Maple and Mathematica in examples picked by Maplesoft

I am reading the document "How Maple Compares to Mathematica" found at http://www.maplesoft.com/products/maple/compare/HowMapleComparestoMathematica.pdf. On page 15 there is an example where ...
24
votes
6answers
1k views

How to understand the usage of Inner and Outer figuratively?

Description: In Mathematica the functions like Thread, Inner, Outer etc. are very important ...
24
votes
1answer
3k views

Programmatically retrieving e-mails from a remote server

Mathematica has a function for sending mail (SendMail) and can import the MBOX format. But what I'd like to do is ...
23
votes
1answer
566 views

On drilling holes with minimal redundancy (and with colors!)

The old Mathematica package Graphics`Shapes` featured the function PerforatePolygons[], which drilled a hole in any ...
18
votes
1answer
530 views

Fast DensityPlot

Is it possible to increase the perforamce the DensityPlot? For example, let's try to plot this "flower" ...
16
votes
1answer
259 views

Extracting road curves from an image

I have taken several gps readings while driving around town. ...
11
votes
2answers
2k views

Machine learning. SVM algorithm

I want to work with machine learning in Mathematica. Are there any SVM algorithms implemented in Mathematica anywhere? Or any other algorithms for machine learning? With positive and negative database ...
10
votes
1answer
132 views

How do I expand StirlingS2[n, 10] in terms of elementary functions?

I know that it is possible to expand StirlingS2[n, 10] in terms of elementary functions of n. I tried ...
30
votes
8answers
2k views

Longest path in 0/1 matrix

I have a matrix of 0's and 1's forming a number of disjoint paths:   I would like to find the lengths of the paths, and from that "spectrum," the longest length (in the above example: 27, ...
28
votes
2answers
903 views

Cleaning mildew from old documents using Mathematica (Image processing)

While visiting family over the holiday period, I managed to have some good mother-daughter bonding over how far back I’ve managed to trace the family tree (Mom is in her 80s and doesn’t do computers). ...
25
votes
1answer
826 views

Calculating a potential function using the finite element method

This is my first attempt to use the Finite Element method available in version 10. There are questions and I am very open to suggestions. My example is flow around a cylinder which is a well known ...
23
votes
4answers
2k views

Buying a new computer (specifically for Mathematica)

My current computer is a MacBook Air, the mid-2011 version: 4 GB RAM, 1.7 GHz Intel dual core. It runs Mathematica 9 smoothly, but a bit too slowly for my taste. I use Mathematica almost exclusively ...
23
votes
1answer
352 views

How to extract a list of available Method-s

The option Methodapplies for several functions, such as NDSolve, FindRoot, ...
22
votes
3answers
1k views

Does parallel programming use up large quantities of memory in Mathematica?

When I start Mathematica with a fresh kernel and load a program I am developing to analyze biology data, the amount of used system memory is 1.9 GB (free memory is 14.5 GB). These memory values are ...
19
votes
1answer
431 views

How to write Morse code into Plot Dashing?

How can we define a dashing pattern in a plot such that it reads arbitrary text in Morse code? For instance Graphics[{DotDashed, Line[{{0, 0}, {5, 0}}]}] ...
19
votes
2answers
768 views

Why does ImageData need four times more memory?

Background We are dealing with very large TIFF image files that are imported, processed and exported using Mathematica 9.0.1. Many of our algorithms only work with an array representation of the ...
19
votes
1answer
300 views

What does “EquationalLogic`FindCounterexample[]” do?

I found the undocumented EquationalLogic`FindCounterexample[] by browsing the lists of available symbols, but I have no clue about its purpose. The name is ...
18
votes
3answers
1k views

Finding a function that fits the shape of an image

How can I find a function that fits the given shape of an image? Or instead extract a point set from the shape and then find an interpolating function fits the shape. An example image is attached.
18
votes
3answers
1k views

Monotone, periodic 1d-interpolation with continuous 1st order derivative

Lately, we had this thread about interpolation where J. M. linked two interpolation methods. The background for my question is that I estimated a parameter in polar coordinates with dependence on the ...
16
votes
2answers
715 views

Schedule programing problem with integer linear programming

I know how to model this question on paper, but I don't know how doing it in Mathematica. Imagine , there is a university student who want to choose courses for this semester and he got the ...
15
votes
4answers
596 views

Exclude data from a list

Let's create some random sample data data = Table[{RandomReal[{-10, 10}], RandomReal[{-10, 10}]}, {i, 1, 300}]; Then we plot them using ...
14
votes
3answers
190 views

What does `: Hold[$IterationLimit]` mean?

In this answer, what does the : Hold[$IterationLimit] part of the following construct do? ...
13
votes
4answers
500 views

How to make a function with its own options as well as passing options to other functions [duplicate]

I have a function with many of its own options, but I would also like to pass options to subfunctions using the FilterRules function. Here's a simple example: ...
10
votes
4answers
2k views

Axis/Angle from rotation matrix

With r=RotationMatrix[a,{x,y,z}] I can compute a 3D rotation matrix from axis/angle representation. Given a 3D rotation matrix ...
31
votes
3answers
775 views

Is there a Mathematica API for the functions.wolfram site?

Is there a Mathematica API for the functions.wolfram site? If there's not, has anyone implemented a web scraper for it? For example it would be nice to be able to access ...
26
votes
7answers
960 views

Graphical representation of a moving sound source

Some explanation since I have got a specific and another more open-ended question: I used two microphones in a 90° arrangement (see picture below) to capture sound from a source moving around the room ...
21
votes
3answers
688 views

Computing polynomial eigenvalues in Mathematica

MATLAB offers a function polyeig for computing polynomial eigenvalues, which appear, for instance in quadratic eigenvalue problems (see here for some applications) such as: \begin{equation} ...

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