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): ...
8
votes
3answers
385 views

Getting a custom bezier curve function to work

In general, $nth$-degree Bezier curve defined as below: $$\vec{C}(u)=\sum_{i=0}^{n} B_{i,n}(u) \vec{P_i} \qquad 0\leq u\leq1$$ $B_{i,n}(u)$ is the classical Bernstein polynomials, ...
8
votes
4answers
358 views

Join two datasets on keys

I want to be able to join two datasets by keys, pretty much like I'd do in SQL. I thought the JoinAcross function might do it, but it doesn't operate the way I thought. The example in the ...
8
votes
4answers
319 views

Fast method to select matrix elements based on a vector of positions

There is an operation for which I have long wanted to find a better solution. Let: a be a matrix of dimensions $m\times n$ ...
8
votes
2answers
314 views

Finding all sets of elements with two common elements in a large dataset

I have a very large network of atoms ($\approx 10^6$ atoms) with fixed positions that resemble a cellular structure: I have two files including: fixed locations of each atom set of points which ...
8
votes
1answer
120 views

Head of a MatrixForm expression?

An example in http://www-zeuthen.desy.de/theory/capp2005/Course/hahn/mathematica.pdf amounts to the following ...
8
votes
1answer
138 views

How to understand shared passing of a MTensor in LibraryLink?

According to the documentation, there are four different type of memory managing when passing a MTensor with LibraryLink: Automatic, "Constant", "Manual" and "Shared". The Automatic and "Manual" is ...
8
votes
1answer
488 views

how to simplify large expression with lots of special functions in it (BesselY, Hypergeometric, MeijerG etc…)

I saw this DE in Maple forum. When solving it using Mathematica 9.01, even though the result was correct (both solutions gave the same numerical answer for some random values), Mathematica's answer ...
8
votes
1answer
484 views

How to calculate the $H_2$ and $H_\infty$ norms of TransferFunctionModels or StateSpaceModels?

Lets assume we have a system model: ...
8
votes
3answers
634 views

How to typeset a system of equations

Is it possible to typeset systems of equations in Mathematica, and if so, how can I do it using a big left bracket as one could in LaTeX with \left\{ ... \.? I ...
8
votes
1answer
151 views

After modifying expression, new result doesn't replace old one

After I modify and re-evaluate an expression, the new result doesn't replace the old one. Rather, what happens is that the old result gets pushed down and Mathematica displays the current result at ...
8
votes
5answers
343 views

correct way to map a function on entries down the pages in a 3D matrix?

updated: added another method to the methods I tried below for completion. This is new way of doing it, but most likely not very efficient, did not time it I can only visualize 3D matrices in my ...
8
votes
1answer
263 views

How to compile Heike's winding number function?

Heike gave the following function for winding number: ...
8
votes
3answers
561 views

Expression of uncertainty in measurement.

I have a problem with writing a Mathematica function. I have been requested to show the results of my experiments with the measurement uncertainty (mu) like below: ...
8
votes
1answer
550 views

Why doesn't FullSimplify get rid of the common factor in this expression?

FullSimplify does not get rid of the z factor in the following expression: ...
8
votes
1answer
83 views

Aborting from inside a Dialog

Suppose I got in a Dialog and wanted to not Return but Abort the computation. How could I do ...
8
votes
5answers
557 views

How to save Manipulate bookmarks permanently?

I would like to save current Manipulate parameter values to load them again later. Bookmarks (previously discussed here and here) work fine until the cell is ...
8
votes
2answers
342 views

Tailoring RegionPlot3D with PlotPoints?

This seemingly tame solid gives Mathematica (v9) a bit of a workout if you want to generate a good picture: ...
8
votes
3answers
160 views

How can I use the overhang argument to Partition to avoid using PadLeft and PadRight here?

Say I have a list of values v = {v1, v2, v3, ... }. I need to partition these values to perform operations with a sliding window (think ...
8
votes
1answer
417 views

Wrapping a rectangle to form a cylinder

I'd like to make an animation showing how we wrap a rectangle to form a cylinder (by joining a pair of parallel sides). Here's my first pass: ...
8
votes
2answers
269 views

Manipulating OptionsPatterns[]

How do you combine OptionsPatterns? For example, I would like to have a function that can take both options that I specify, and options for all graphs: ...
8
votes
2answers
304 views

Trouble getting FindInstance to return multiple results for certain constraints

I'm having a hard time getting FindInstance to return multiple results. Consider this simple example: ...

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