11
votes
1answer
2k views

Make a density list plot/histogram from large, pre-binned data set?

I have a large data set consisting of $\mathcal{O}(10^9)$ two-dimensional points. In order to save memory and time I have pre-binned these into a uniform grid of $500 \times 500$ bins using Fortran. ...
11
votes
4answers
510 views

Assessing argument type in set delayed function definitions

I'm wondering how to properly assess the type of arguments passed to functions defined with :=. I want my functions to be the most efficient, unambiguous and clear ...
11
votes
2answers
574 views

What's the most “functional” way to do Cholesky decomposition?

I can do Cholesky in a procedural style, such as: ...
11
votes
1answer
260 views

Old values are not freed/garbage collected when you re-evaluate an assignment

For this code: (* Cell 1 *) generate := Module[{x}, x = Range[100 * 1000 * 1000]; x]; (* Cell 2 *) g = generate[]; MemoryInUse[] If I evaluate cell 2 ...
11
votes
7answers
2k views

Combination and Permutation

How could I obtain the list of all the groups of 5 numbers taken from Range[12] such that the 2 lists have an empty intersection : ...
10
votes
0answers
68 views

Unexpected pattern matching behaviour: PatternSequence vs. Optional

Consider the following pattern-matching expressions: ...
10
votes
2answers
224 views

Is there a way to control V10's undo length?

This may be a duplicate (if so I will remove this), but I was having trouble finding the relevant bit of documentation to fix it. I noticed that my FrontEnd memory ...
10
votes
1answer
499 views

Are there tools for getting Mathematica 9 Notebooks working in Mathematica 10?

As often happens with Mathematica updates, nearly all of my notebooks no longer work as they did with the previous version. The upgrade from 9 to 10 has changed the appearance or introduced errors ...
10
votes
1answer
197 views

Why is my rasterized graphic blank?

Consider the following code: ...
10
votes
2answers
408 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
7answers
649 views

How can I Flatten this List with Inner List of Lists?

Given the following List ...
10
votes
1answer
164 views

Are formal characters like \[FormalA] to be used differently than other symbols?

I noticed that Mathematica has a set of special 'Formal' characters such as \[FormalA], \[FormalB] , etc.. In the front end, it ...
10
votes
2answers
605 views

How to send output of Information[] command to a text file?

I am having little hard time sending output of Information[] command to a text file. related question How to write output to an external text file in addition to ...
10
votes
4answers
449 views

How to use pattern matching to assign values to Subscript[f,x_]?

I want to define two subscripted functions Subscript[f,1] and Subscript[f,2]. To keep the assignments local, I would like to ...
10
votes
2answers
794 views

Preventing label crowding in PieChart RadialCallout and RadialCenter

Is it possible to avoid this unreadable situation with label crowding when using PieChart's RadialCallout and ...
10
votes
3answers
684 views

Count consecutive positions with the same value

I want to program a function that counts the successive positions with the same value: In[]= ConsecutiveValues[{1, 1, 1, 1, 2, 2, 1, 0}] Out[]= {4, 2, 1, 1} In ...
10
votes
2answers
248 views

Encoding format used by GraphicsData?

I am trying to extract some graphics stored in PICT format from a Mathematica notebook, using a platform that doesn't support PICT. If I look at the .nb file in a ...
10
votes
1answer
453 views

Mathematica Source-Code Control for CDF files in multi-user scenario

Q: I'm putting together a strategy on how its best to maintain cdf documents with multiple users in a source code repository. Ideally I wish for users to create (unit tested) cdf's with data and ...
10
votes
4answers
5k views

subscripts in plot axis labels

Superscripts can be included in axis labels by the use of the caret symbol (e.g., Plot[x^2, {x, -1, 1}, AxesLabel -> {x, x^2}]). How does one include subscripts ...
10
votes
3answers
848 views

Passing down arguments

In R, one can use ... to pass arguments down to another function. For example ...
10
votes
3answers
1k views

Most Efficient Way to Calculate the Product of All Items in a List?

Say that I have a list of returns on a financial asset over time and want to know the total compounded return. To get the answer, I need to add 1 to each return and then calculate the product of all ...
10
votes
5answers
544 views

How do you efficiently return all of a List but one element?

I have a problem that I am working on that requires that I compare several lists of overlapping data points. As I traverse one of the lists, I'd like to only compare those data to the other lists, and ...
9
votes
1answer
87 views

Installing LinkSnooper on Windows

I tried to install LinkSnooper on my Windows 7 computer, as described in the documentation and here. According to the answer of @Todd Gayley, I entered the following string in the field MLOpen: ...
9
votes
2answers
817 views

Solve Laplace equation using NDSolve

I am new to Mathematica, a friend recommended this software and started using it, in fact download the trial version to know. I recently did a program in C to calculate numerically the solution to ...
9
votes
1answer
347 views

Converting structured data to a dataset

A Dataset seems perfect to represent structured data. Has anyone already thought about how to convert as efficiently/elegantly as possible an XML or JSON file to a Dataset in Mathematica 10 ?
9
votes
2answers
2k 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
2answers
524 views

Memory leak issues

I am working with noncommuting objects and basically I am using Mathematica to sort large expressions by normal ordering and simplifying them. To this end, I first create an object called ...
9
votes
3answers
13k views

MathLink linking error after OS X 10.9 (Mavericks) upgrade

After macosx 10.9 mavericks upgrade i have a compilation problem, you can see below. Even the examples given in ...
9
votes
4answers
410 views

When should I use Apply (or Function) and when @@ (or &)?

This is a rather general question, which I fail to answer myself. I guess it is mainly due to my insufficient knowledge of the precise terms. If I understand correctly, the following are equivalent: ...
9
votes
1answer
266 views

Efficiently filling area with disks located at certain points

Starting from a set of points, I want to fill an area using disks. Each disk's center should be one of the points and the disks should not overlap. I've managed to write a function that, given a list ...
9
votes
2answers
304 views

Is there a way to programmatically set global preferences?

Can I set global preferences that are accessible via "Edit"->"Preferences" programmatically from within a notebook? As learned from this question, turning off anti-aliasing can make a huge difference ...
9
votes
2answers
540 views

Extracting vertex coordinates from an automatically laid out graph

Given a Graph with an automatically computed layout (i.e. not explicitly given VertexCoordinates, but using a ...
9
votes
2answers
321 views

Transition between graphs

I want to visually demonstrate the manipulations made to a graph. For instance, I have a graph g where using the command ...
9
votes
3answers
379 views

Why is AstronomicalData so slow?

I'm having trouble getting some pretty simple functions using AstronomicalData to perform at anywhere near the speed I need them to. For example, I have many ...
9
votes
2answers
236 views

Strange results while nesting scope constructs?

I did a handful of tests with Block, With, and Module and had a couple of new surprises. ...
9
votes
3answers
518 views

Different calculation of median and quartiles, bug in BoxWhiskerChart?

When you plot a dataset with BoxWhiskerChart passing over the box in the plot with your mouse pointer shows some specifics about the dataset (min and max values, ...
9
votes
3answers
649 views

Improve speed for calculating a recursive sequence

I want to calculate following recursive sequence: $\alpha_{0}=0,\\ \cos(\alpha_{i})=\cos(\alpha_{i-1})\cdot\cos(\beta_{i})+\sin(\alpha_{i-1})\cdot\sin(\beta_{i})\cdot\cos(\gamma_{i}).$ In ...
9
votes
3answers
407 views

How to use Locators on a graphic in a tabview

Background: I want to split graphics in a Manipulate in several parts in a tabview control. But the tabview somehow interferes with the locators as in the following simplified example: ...
9
votes
1answer
293 views

How can I add row and column header images to my TableForm output?

I am experimenting with the Eigenfaces algorithm and have my notes and experimental data collected in a Mathematica notebook. The result of an experimental run is a table of scores, where the smallest ...
9
votes
1answer
171 views

Is there a way to have a Tooltip for non-editable raster graphics produced by MakeBoxes?

I have a function which produces a large object I would like to hide. Formatting is of course an option but I'm hoping for something a little more meaningful using raster graphics and ...
9
votes
1answer
275 views

SubTitle and SubSubTitle do not group by default

For some reason, the SubTitle and SubSubTitle cell formats do not group automatically on my machine any more, and I cannot ...
8
votes
5answers
388 views

What is my problem with MeshFunction?

I want plot the max value in a sine plot. We can use the following code ...
8
votes
1answer
200 views

Inconsistent DistributionFitTest results?

In pondering this question, I used Mariana's function to generate the following data. ...
8
votes
2answers
201 views

The introduction for Context in Wagner's book is out of date? [duplicate]

In Section 8.1.1 (P230 of the book, P249 of the PDF) of Wagner's book, the following example is shown: x = 5; temp`x = 6; Begin["temp`"]; {x, Global`x} The ...
8
votes
3answers
313 views

Deleting quasi-duplicates from large list efficiently

I have the need to remove "duplicates" from large (>10K members) lists, where a "duplicate" is either a verbatim duplication, or the element's second entry exists as a first entry for some "earlier" ...
8
votes
2answers
344 views

Goto and Compile

...
8
votes
1answer
307 views

How to convert Graphics3D object into an Image3D object?

How does one convert a Graphics3D object into an Image3D object? E.g., start with ...
8
votes
1answer
305 views

How can I define a Listable function only apply to a vector?

Consider the function f which should behave as f[{{1, 2}, {3, 4}, {5, 6, 7}}] ...
8
votes
1answer
196 views

Unexpected behaviour of Solve applied to two equations in two variables

I have a simple Mathematica expression Solve[{a(a-1)Sqrt[1+a^2+b^2] == b(a^3-1), b(b-1)Sqrt[1+a^2+b^2] == a(b^3-1)}] which returns (on version 8.0, and also ...
8
votes
3answers
190 views

Preserve information in flattening a nested list

I have a series of lists in the form below: list={ {1,1} , {2,2}, {3,{3,1},{3,2},{31,{31,1},{32,2}}} } Its a nested list which the dimension is changing case to ...

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