11
votes
2answers
204 views

Graph smoothing keeping vertices fixed?

Context Given a Graph like this one: ...
11
votes
1answer
256 views

Making a Mathematica package manager?

I'd like to get a serious discussion started about a package manager. This has come up elsewhere, and many people have implemented their own solutions. It would be nice to have a standardized way to ...
11
votes
0answers
150 views

Graphics`Mesh`FindIntersections[ ] fails to detect intersections

Graphics`Mesh`FindIntersections[ ] is an undocumented function for, well, detecting intersections very efficiently. Take a look: ...
11
votes
1answer
376 views

Dynamic visualization of Graph[] on a webpage

How can we embed a dynamic version of a Graph object on a web page, similar to the one showcased on the networkx home page? This sort of dynamic visualization can ...
11
votes
2answers
546 views

Finding the perimeter, area and number of sides of a Voronoi cell

Does anyone have any suggestions how to determine the perimeter, area and number of sides of each Voronoi cell in Voronoi diagram?
10
votes
2answers
202 views

Temporal database reconstruction in mathematica

<EDIT> after some internet research I found the database domain that deals with this kind of thing: Temporal Databases. I think my question therefore becomes how to reconstruct a temporal ...
10
votes
1answer
288 views

How can I extract the outline of bubbles in my image?

I have an image: I tried to extract the outline of the bubbles, but I met with some problems. Firstly I tried the method used in Mathematica documentation for ...
10
votes
4answers
435 views

Exporting data extensions in fits file

Context In Astronomy the de facto standard for images and data is FITS. I would like to export heterogenous data sets into a single fits file. Attempt I am ...
10
votes
2answers
674 views

How to position text labels automatically to not overlap other graphics elements?

I was plotting reciprocal frame projection using Locators for a point to be expressed in terms of both the original basis (also specified with ...
10
votes
1answer
690 views

Roads network visualization by thickness and color intensity by population from GIS files

We can have road networks of the countries in GIS shape file.For exmple from here. Normally traffic flows are proportionate to populations of the cities. I wonder how we can have the same in ...
10
votes
4answers
288 views

Searching linked lists that contain lists?

Following the advice I've read here and other sites, I've been trying to use the Mathematica equivalent of a linked lists... ...
10
votes
5answers
596 views

Relational joining of tables

A common thing to want to do with data is to combine it (at least I thought this was a common thing). In SQL there is the idea of table joins "select id,v1,v2 from A,B where A.id=B.id" kind of thing. ...
9
votes
4answers
3k views

How to plot periodic function's graphic?

How to plot periodic function's graphic? For example, f(t) = t when -5<t<5 && f(t+10) = f(t) ...
9
votes
2answers
279 views

Manually specifying distance metric to Nearest slows down calculation

Why does manually specifying the distance metric to Nearest slow down the calculation so much? This is relevant to my previous question. I've been using ...
8
votes
1answer
163 views

Expanding derivatives of hypergeometric functions

Sometimes Mathematica expresses results of integration or summation in terms of symbolic derivatives of Hypergeometric2F1 function, and cannot further simplify ...
8
votes
5answers
511 views

Is there a built in function to obtain the back diagonal of a matrix?

Given the following matrix: m = Array[Subscript[a, #, #2] &, {4, 4}] how can I find the skew diagonal or anti-diagonal or back diagonal of the matrix ...
8
votes
2answers
743 views

OpenSCAD like functionality with Mathematica?

I keep seeing reference to use of Mathematica as a CAD tool (for instance: http://www.makerbot.com/support/guides/design/). I'd like to use it as such if feasible, but I'm having trouble locating ...
7
votes
1answer
251 views

Import iTunes xml data and convert it into a dataset or table

I have an xml file with song data from iTunes (https://dl.dropboxusercontent.com/u/1012958/iTunes%20Library.xml) and I'd like to import it to Mathematica to do some statistics. I get an XMLObject like ...
6
votes
2answers
306 views

Exporting BarChart3D as PDF produces artefacts

So I think the following image already shows the problem, similar to Avoiding white lines inside filled area in RegionPlot exported as PDF or PS the pdf export of the chart creates thin lines in the ...
5
votes
1answer
886 views

Hodrick–Prescott filter (one-sided version)

I am interested in implementing Hodrick–Prescott filter (HP filter) on my time series data in Mathematica. I know that there is already a version of two-sided original filter for Mathematica (see ...
5
votes
2answers
954 views

Extracting polygons from 3D contour plot surface

Edit: This question turned out to be two parts so I am going to make this question about only the first part a kguler provided an excellent answer. Here is a better representation. My actual data ...
28
votes
2answers
844 views

DeleteDuplicates not deleting duplicates

It is not surprising that DeleteDuplicates[{5,5.}] returns {5,5.} because DeleteDuplicates ...
25
votes
0answers
326 views

Are greek symbols causing different evaluation?

I've updated today to Mathematica 9.0.1.0 from version 8 and found something that absolutely confuses me. Let us define a piecewise function: ...
25
votes
2answers
536 views

Should 0 * 5ft be 0 or 0ft?

After playing with the new quantity system in Mathematica 9 for a while, I keep stumbling over this issue: 0 * Quantity[1, "Meters"] is not the same as ...
22
votes
3answers
370 views

Efficiently appending points to a NearestFunction

I have a program which works with a list of points (in 3D, but it could be in 1D as well, it won't make a difference). Within a loop, it keeps adding new points to the list. To calculate the ...
21
votes
2answers
701 views

Is there a Mathematica barcode reader?

Is there a Mathematica barcode image reader (much like TextRecognize) that allows the user to enter an image of a barcode and then read it to get an output string?
21
votes
10answers
2k views

How to convert a hex color string to RGBColor?

For example: "#FF8000". How could I convert it to RGBColor or Hue?
20
votes
3answers
455 views

Real Numbers in the Wolfram Language

Epilog: Much of the discussion in the answers below revolves around the distinction between Real as a data type and real numbers as a domain or class of numbers (irrespective of the form in which ...
20
votes
2answers
229 views

BitShiftRight produces incorrect results in Version 10

fixed in 10.0.2 With Mathematica 10 for Mac, BitShiftRight works properly on lists of up to 100000 numbers, but appears to give incorrect results when threaded ...
20
votes
3answers
874 views

Strip waste braces in nested list

I have nested lists wherein there are a lot of waste levels which looks like l = {{{{{{2, 2}}, 3}, 2, {{2, 33}}, 4, 5}}}; I would like to reduce it to somthing ...
20
votes
7answers
1k views

Elegant and fast way to join all string sequences

I want to do what title says: {"a","b",1,2,3,4,"a",2,2,2,"edg","?"} => {"ab",1,2,3,4,"a",2,2,2,"edg?"} in the most elegant way. For example one replacement rule for ...
20
votes
3answers
2k views

Programming a numerical method in the functional style

I am new to Mathematica and I would like to learn a bit more about functional programming. At the moment I have assignments like programming different numerical methods (for integration: ...
20
votes
5answers
992 views

In a ListPlot of LinearModelFit, Fill to the regression line

In the help for LinearModelFit, the regression line can be added to the scatter plot like this: Show[ListPlot[data], Plot[lm[x], {x, 0, 5}]] Is it possible to ...
20
votes
1answer
1k views

Using ImageCapture to access a USB webcam in linux

Is it possible to access a USB webcam through Mathmatica on Linux? When I run ImageCapture[] I get the following output ...
18
votes
1answer
443 views

Color scheme used by Colorize?

The Colorize function is often used to display the results produced by MorphologicalComponents: ...
17
votes
1answer
292 views

Why some built-in functions are slow

I just wonder why some built-in functions are slower compared to some other ways using more than one built-in functions for doing same job. consider this example: ...
17
votes
3answers
635 views

Can CDF file embedded in a web page receive external parameters?

I know that I can embed a CDF file inside a web page by using: The embed tag. An object tag with an embed tag inside (better than 1). Using the JavaScript provided by Wolfram (better than 2). My ...
16
votes
2answers
394 views

A better “VisibleSpectrum” function?

Since ColorData["VisibleSpectrum"] is wrong I would like to have a more accurate function to use. Can this information be extracted from Mathematica itself?
16
votes
1answer
247 views

Bug in RepeatedNull?

RepeatedNull appears to be buggy (versions 8.0, and 9.0). Define f as follows: ...
16
votes
1answer
192 views

Standard message definition construct

Why are the messages almost always defined like this (at least in packages): If[Not@ValueQ[function::usage], function::usage = "Usage message"] and not just like ...
16
votes
3answers
487 views

How to get complete Documentation Center graph of guide pages?

On the very last image below you can see a typical path of walking through Documentation Center guide pages. What is the best way to get the graph data and visualize the whole structure of these ...
15
votes
3answers
1k views

Drawing a square root spiral

Here is a start, i'm looking for a nice way. ...
15
votes
0answers
139 views

A bug in the overloading of MemberQ and FreeQ for Association?

Bug introduced in 10.0.0 While answering Pattern match for nested Association I came across behavior of MemberQ and FreeQ in ...
15
votes
1answer
429 views

List of atomic expressions

I was surprised to see Graph objects are atomic. Is there a way (through documentation or programmatically) to find all atomic heads? The ones I know of are: ...
15
votes
1answer
313 views

Unpacked eigenvectors of complex matrices

Edit: This bug is fixed in Mathematica 10.0.0 I want to calculate eigenvectors of a Hermitian matrix. For example ...
15
votes
1answer
409 views

Find elements in a decay chain using IsotopeData

I am trying to write a program using the Mathematica function IsotopeData, but am finding the code troublesome. Due to my (relative) familiarity with Python, I am ...
15
votes
2answers
689 views

How to define a non-standard algebra in Mathematica?

I want to define an algebra, where there are three elements: 0, 1 and $\infty$ and two operations, addition and multiplication defined, both commutative: $$\begin{align*} 0+0&=0\\ 0+1&=1\\ ...
14
votes
12answers
608 views

Join lists with nested list

Is there a way of smarter way of joining list of the form l1 = {a,{b,c}}; l2 = {d,{e,f}}; l3 = {g,{h,i}}; To obtain ...
14
votes
6answers
561 views

How can I suppress rotation of 3D graphics?

Given a 3D image built of a combination several Graphics3D objects, is it possible to suppress rotation of the displayed image by the mouse? To be specific, here ...
14
votes
5answers
1k views

Make legend same height as plot

One common style for density plots is to have a vertical legend that is the same height as the plot itself. Some example density plots from Google Image search: How can we make DensityPlots with ...

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