11
votes
5answers
258 views

Construct an infix operation from a list

Inspired by this question, if I have a list {a, p, b, q, c} where p and q are binary ...
11
votes
3answers
929 views

Derivatives (divergence, gradient, curl) of interpolated 3D data

How can I calculate a vector derivative (i.e. divergence, gradient, curl) of interpolated data? For sample data, you can use: ...
11
votes
3answers
174 views

Emulating Sequence with my own function

I just considered if/how one could implement Sequence in Mathematica if it were not predefined. It turned out that the following simple definition has in all my ...
11
votes
2answers
602 views

Google Code Jam: Mountain View code review

After participating in Google Code Jam 2012 Round 2, it occurred to me that the Mountain View problem boiled down to solving a set of linear inequalities, which could be done in Mathematica. I've only ...
11
votes
7answers
326 views

Question about evaluation control

I want to make a function that takes a function as a parameter and prints an integral with the function inside. I've tried this: ...
11
votes
1answer
1k views

How to export transparent raster plots?

Is there an easy way to get transparent plots that work with Save Graphic As using a compatible file format such as GIF or PNG? I tried ...
11
votes
3answers
258 views

Numbers in alternate bases transcend the evaluator?

It looks to me like a number in a base other than base 10 gets evaluated before the evaluator ever gets a chance to be tweaked. For example, FullForm[16^^abcdef] ...
11
votes
2answers
664 views

How to plot a barycentric line

I want to plot a barycentric function on an equilateral triangle (ternary plot). For example f1 = {Abs[Sin[x]], Mod[x, 2], Abs[Cos[x]]}; At the moment I evaluate ...
11
votes
4answers
731 views

How do I get rid of the overlap of gridlines and tick mark labels?

I wish to include the plot generated by the following Mathematica code ...
11
votes
3answers
2k views

Poor rendering of fractals

Could someone explain why I get those ugly graphics .. ..trying to use fractals in mathematica 8 ? I'd also like to know if it is possible to draw 2D fractals in Mathematica My configuration ...
10
votes
5answers
820 views

The mysterious gap inside Grid

There's this gap inside Grid which I cannot seem to remove. Perhaps someone knows how. ...
10
votes
4answers
267 views

No response to an infinite limit

Trying to compute this limit, things seem to get frozen, even for hours. What would you recommend to fastly compute it? ...
10
votes
1answer
475 views

How do I place a texture on an irregular 3D model?

I'm trying to reproduce a textured head in Mathematica, and I'm using a kind of 'net' of a head which contains all the features on the face. The texture looks like this: which is supposed to look ...
10
votes
1answer
207 views

Is there a method to enumerate the keys/values of System`Utilities`HashTable

Lacking from the simple API of System`Utilities`HashTable is a method to enumerate the keys/values. ...
10
votes
2answers
379 views

How can I access the internal function that plots a molecule from a formatted XYZ file?

Mathematica has the ability to plot a molecule using the data contained in an XYZ file. This is a simple text file, of which this is an example. The molecule is plotted using the Import command. ...
10
votes
1answer
389 views

How to make a volume CUDA rendering isometric?

I just realized that the output of CUDAVolumetricRender[] uses (quite marked) perspective, which I do not want (for scientific data representation, it can be very ...
10
votes
1answer
647 views

NDSolve Differential Equation Error

I am trying to solve the following differential equation- ...
10
votes
1answer
202 views

Unexpected result from Flatten

Consider the following three evaluations involving Flatten: Flatten[f[f[f[x, y], 1, 2], f[x, y]], Infinity, f] f[x, y, 1, ...
10
votes
1answer
191 views

Why do DateList, DateString, and AstronomicalData ignore $TimeZone?

My reading of the documentation for DateList and DateString lead me to believe that both functions use ...
10
votes
5answers
807 views

Implementing CGS unit system in Mathematica 9

So I've just installed the trial version of Mathematica 9. The first noticeable feature for me is the new built-in physical units. I used AutomaticUnits package ...
10
votes
2answers
356 views

Determining the default Method used in optimization and root-finding algorithms

Is it possible to extract the Method which is used in functions like NMinimize, FindRoot, ...
10
votes
3answers
545 views

Mathematica Plot: Inconsistency when plotting large values

I am working with a function in Mathematica and I am getting some inconsistencies when I plot it. As I really need to understand were this comes from I would appreciate any help. I am working with a ...
10
votes
2answers
401 views

Animation: presenting events that persist in time

I have a list of events that occurred on specific moments in time. In the example below, the three events occurred at 23:09, 23:13 and 23:17. I was able to build an animation that flows from time ...
10
votes
4answers
1k views

How do I plot Thomae's function in Mathematica?

I wanted to plot this function $$f(x) =\begin{cases} 1 & \text{if } x= 0 \\ \tfrac1{q} & \text{if } x = \tfrac{p}{q}\\ 0 & \text{if } x \in \mathbb{R}-\mathbb{Q} ...
10
votes
2answers
169 views

Subtle difference in conditional rules placement

I had gotten used to thinking of the placement of a condition in a rule definition as logically immaterial. In my specific example, namely ...
10
votes
4answers
723 views

Efficiently Visualising Very Large Data Sets (without running out of memory)

I have put a few really hard problems in combinatorics up against Mathematica 8. I'd have to say that it works really well, until you want to view the data. If you look at my question Advanced ...
10
votes
1answer
492 views

How to import date (YYYY-MM-DD) data from a file?

I have a file with data in form {date, value}: 2010-05-19 17 2010-05-20 20 ...
9
votes
1answer
186 views

PlotLegends won't generate automatically more than 15 labels in v10

NOT fixed in v 10.0.2 (Dec2014) While testing the examples from this recent post, i've noticed a problem in V.10 with PlotLegends when it has to automatically ...
9
votes
1answer
128 views

Tracking Initialization

How to track Initialization step by step? Any tricky solution is ok. One condition, x should be ...
9
votes
2answers
173 views

Extracting values with multiple keys

I want to extract sorted data from a huge database based upon two (or more) keys in a very timely manner. Here is a reproducible toy example for two keys only: ...
9
votes
2answers
1k views

Why is this semicolon in red?

I have a piece of code that works well, but when I put a semicolon after a plotting statement, the semicolon appears in red. What's the error?
9
votes
1answer
403 views

What is the proper way to verify that two expressions are equivalent?

First of all, it appears to me that $$\left|\frac{1}{x} + x^2\right| \Leftrightarrow \frac{|1 + x^3|}{|x|}$$ is true. I don't know why, but my attempt to verify it in Mathematica failed. ...
9
votes
3answers
440 views

How to visualize the interior of a complicated 3d plot

I have an external data file (can be downloaded here: link 1 or link 2) which contains a dense grid of initial condition in the (x,y,z) space. I read it with Mathematica and plot these initial ...
9
votes
2answers
327 views

Recursive Integral for Volume of $n$-Ball

The volume of an $n$-ball (the $(n+1)$-dimensional analogue of a disk) of radius $r$ can be found by the following integral recurrence: $$V_0(r)=2r$$ ...
9
votes
5answers
371 views

Count consecutive occurrences in a list above a certain value

I am trying to tally and sort the number of consecutive occurrences in a list above a certain value. For instance: ...
9
votes
1answer
128 views

What are the scoping rules for function parameters shadowing System` symbols?

Here are some very contrived code snippets, highly unlikely to appear in real code, but still I am curious why they behave like this: ...
9
votes
3answers
398 views

FindShortestTour for charity (or: How can I optimize meal delivery with FindShortestTour?)

I've been wondering about this for a while - but never got around to asking - until I saw faleichik's incredible answer to Mathematica Minecraft. I did some work at a not-for-profit a little while ...
9
votes
1answer
420 views

FourierSeries for rational function looks wrong

I have the following code: ser[x_] = FourierSeries[(\[Pi]^2 + a)/(3 x^2 + a), x, 10] // N // Chop It gives me some series, which I then try to plot. And ...
9
votes
2answers
276 views

Determining whether two $k$-chromatic graphs are isomorphic (respecting vertex coloration)

Consider the case where I have two $k$-chromatic graphs $G_1$ and $G_2$, i.e. two graphs where individual vertices can be colored with one of a set of $k$ total colors, and I would like to determine ...
9
votes
2answers
327 views

Speed up 4D matrix/array generation

I have to fill a 4D array, whose entries are $\mathrm{sinc}\left[j(a-b)^2+j(c-d)^2-\phi\right]$ for a fixed value of $\phi$ (normally -15) and a fixed value of $j$ (normally about 0.00005). The way ...
9
votes
3answers
668 views

Forest plot with Mathematica 9

Does anyone have experience with or a package for the creation of forest plots in Mathematica 9? For instance for subgroup analyses of cox model or meta-analysis (e.g rmeta package in R)?
9
votes
0answers
325 views

Proving (self) similarity with Mathematica - Reccurrence Plots, Similarity Plots etc

I posted this question in math.se but given the sheer tumultuous number of questions that keep appearing on math.se and also given that I am trying to accomplish this in Mathematica, I thought I'd ...
9
votes
2answers
911 views

How to calculate mix of 4 colors defined in CIELAB L*a*b* model?

I have 4 colors that I converted from RGB to CIELAB L*a*b* model. How can I calculate mix of these 4 colors when I have (L,a,b) for each such color? How can I ...
9
votes
2answers
785 views

How can I animate a set of points imported from file?

I have an external program which generates a set of data - X points at the time t1, X points at the time t2 and so on. These points are stored in CSV file and I can change the format if necessary. ...
9
votes
1answer
2k views

Using RegionFunction on multiple plots

I realize that the Plot function can plot multiple functions of x at the same time, using { }. I also know that the ...
9
votes
3answers
1k views

Importing HDF5 with compound data

I am looking to Import HDF5 data with compound data. It appears, at least from what I read, that Mathematica 8.0.4 (and previous versions) does not support reading ...
9
votes
3answers
568 views

Ctrl+= opens the alpha input instead of below-script

When trying to type "traditional style" inputs such as integrals or sums, I follow the tutorial and type Esc sum Esc   Ctrl+= n=1  Ctrl+% 10 whatever However, when I type Ctrl+= it opens ...
9
votes
1answer
782 views

Changing default window appearance

Since every single time I start Mathematica, my first action is aligning the windows properly (Notebook on the left for $2/3$ of the screen, help on the right for the other $1/3$), I was wondering ...
9
votes
2answers
191 views

Checking from a preemptive evaluation whether a main evaluation is ongoing

How can I programmatically check from a preemptive evaluation whether a main evaluation is currently ongoing? I need a function mainEvaluationOngoingQ[] so that ...
8
votes
2answers
292 views

Recursive partitioning: Is there a better way to do this?

Consider the following function, which recursively splits a list into equal length sublists (the length of the list is assumed to be a power of the second argument): ...

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