Questions on undocumented functionality of Mathematica. Note that such functions might be subject to change without notice in future versions.

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107
votes
5answers
4k views

How can one find undocumented options or option values in Mathematica?

Mathematica has a lot of undocumented or poorly documented options. How does one go about working out if there is an undocumented option that might solve a particular problem? How does one work out ...
89
votes
11answers
4k views

What are some useful, undocumented Mathematica functions?

There have already been some questions about some undocumented functionality in Mathematica. Such as (please add to these lists!) How can one find undocumented options or option values in ...
47
votes
2answers
2k views

Internal`Bag inside Compile

Since Internal`Bag, Internal`StuffBag and Internal`BagPart can be compiled down, it is a ...
42
votes
1answer
1k views

How can I manipulate TemporalData?

Version 9 introduced TemporalData but, truth be told, the documentation doesn't suggest that one can do much with it. Many of us have probably assumed we'd be ...
36
votes
6answers
1k views

Items known by CurrentValue

CurrentValue can be used to poll the state of numerous system values such as the mouse position. Its help page doesn't list all possible items, though. An item like ...
35
votes
1answer
768 views

What's inside InterpolatingFunction[{{1., 4.}}, <>]?

I'm curious what's inside the InterpolationFunction object? For example: ...
31
votes
4answers
617 views

Any ideas on how to use the Region` context?

If you type ?Region`* you'll get: which seems a bunch of interesting and not documented symbols. Any idea (or experience) on how to use them? Edit By ...
30
votes
1answer
3k views

Does Mathematica support variable frame rate for any video format, in analogue of GIF-style “DisplayDurations”?

The good old GIF animation format allows us to set the duration of each individual frame in the animation separately. This is especially useful if some frames in ...
28
votes
4answers
625 views

Undocumented form for FilledCurve[]

New in Mathematica 8 is FilledCurve (and its cousin JoinedCurve). The docs state that this function can take a list of segments ...
28
votes
4answers
1k views

Question about collections of custom GUI controls for Mathematica

Background: I have only recently begun programming GUIs in Mathematica, so I have a continuous need for custom controls. I needed a scrollable list control and with the help of Google I found a ...
25
votes
1answer
278 views

What does Internal`InheritedBlock do?

What does the function Internal`InheritedBlock do? How is it different from the regular Block?
25
votes
1answer
616 views

How do I find all the possible events that work with EventHandler?

The EventHandler documentation, More Information section, lists 5 mouse events: ...
25
votes
1answer
615 views

Undocumented form for Extract

Prompted by a comments conversation here, here's an interesting (and often performance enhancing) use of Extract: ...
24
votes
0answers
330 views

Documentation of the frequently-used functions in the context of Internal` and Compile` [duplicate]

In this site, I have gradually found out that there is a collection of functions in all kinds of answers. For instance, Compile`GetElement, ...
23
votes
3answers
785 views

Is using undocumented functionality a Bad Idea™?

Mathematica has a lot of very useful undocumented features. For example a hash table, a built-in list of compilable functions, additional options to CurrentValue, ...
23
votes
1answer
780 views

Undocumented use of Integrate: Integrating over regions

I have come across a few questions asking about integrating over regions. And while the answers are impressive there should be a better more consistent way. So my question is, are there ways, ...
22
votes
1answer
483 views

How to work with Experimental`NumericalFunction?

This question is intimately connected with previous one: "How to create internally optimized expression for computing with high WorkingPrecision?" Oleksandr R. correctly states in the comment: A ...
21
votes
2answers
535 views

How to write beveled fractions?

How to write beveled fractions like ${}^a/_b$? In contrast to $\frac{a}{b}$ and $a/b$ (see this question).
20
votes
2answers
433 views

What are all the named Mathematica styles?

This question came to mind because of this answer to a recent question. Under Style, the Mathematica Documentation Center says the following about named styles. A few common named styles ...
19
votes
2answers
518 views

Specifying non-conflicting PlotTheme options

A bug or limitation in 10.0.0 affects a few of these examples; it was resolved in 10.1.0. I am trying out Mathematica 10 on https://programming.wolframcloud.com. ...
19
votes
1answer
302 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
1answer
522 views

What does ImageSize -> 1 -> 1 mean?

On the page http://www.wolfram.com/language/gallery/blur-faces-in-an-image/ the example code has ImageSize -> 1 -> 1. I am unfamiliar with this chaining of ...
17
votes
1answer
352 views

What are SparseArray Properties? How and when should they be used?

A strange undocumented form of SparseArray is increasingly used in answers on this site: ...
17
votes
1answer
417 views

What is the meaning of the last argument passed to the ColorFunction of a ParametricPlot3D?

According to the docs, the meaning of the arguments passed to ParametricPlot3D is $x, y, z, u, v$. This is 5 arguments: the Cartesian coordinates and the two ...
17
votes
1answer
174 views

Reading from a socket stream

I noticed an undocumented socket package (SocketLink) in Mathematica (Using version 10, not sure when it was actually added) and wrote a barebones HTTP responder ...
16
votes
1answer
253 views

In 10.1.0 BenchmarkPlot doesn't work?

In Mathematica 10.1.0 BenchmarkPlot from the GeneralUtilities package doesn't work; copying Taliesin Beynon's initial use of the function on this site: ...
15
votes
2answers
301 views

What is the purpose of Internal`LocalizedBlock?

I have come across the (internal) use of of the function: Internal`LocalizedBlock I am trying to determine its purpose. It seem to behave like ...
15
votes
1answer
228 views

The second argument of Signature

I've noticed that Signature can have an undocumented second argument. What does it do? Signature[{1,2,3,4}, ?]
15
votes
0answers
185 views

Graphics`Mesh`FindIntersections[ ] fails to detect intersections

Graphics`Mesh`FindIntersections[ ] is an undocumented function for, well, detecting intersections very efficiently. Take a look: ...
14
votes
0answers
493 views

Undocumented syntax of FilledCurve [duplicate]

Possible Duplicate: Undocumented form for FilledCurve[] A nice trick to get the outline paths of letters is to use the PDF exporter/importer ...
13
votes
2answers
348 views

Internal “Periodical” functions in version 7

In version 7 there exist these Internal` context functions: ?Internal`*Periodical* ...
13
votes
1answer
132 views

How to retrieve current FaceForm?

The current colour in a Graphics object can be retrieved using CurrentValue["Color"] for use in Dynamic stuff. Example: ...
12
votes
3answers
307 views

In InputField, how to prevent Shift-Return from generating a new cell?

When running the following in a notebook (not a deployed CDF file), it can sometimes be annoying that accidentally pressing Shift-Return breaks out of the user ...
12
votes
2answers
313 views

Behavior of Reduce with variables as domain

When using Reduce, I accidentally put a set of variables as the domain. To my surprise, it not only seems that Reduce expects ...
12
votes
2answers
172 views

Listable functions thread over Associations; is this documented?

Thanks to a somewhat misapplied use of MapThread I learned of this behavior: ...
11
votes
1answer
156 views

Is there a way to control which special forms Normal converts?

Normal documentation reads: Normal[expr] converts expr to a normal expression, from a variety of special forms. But is there a way to control which special ...
11
votes
1answer
329 views

What is the complete list of valid FrontEnd Packet types?

In response to my question How can I get the unchanged Box form of an arbitrary expression? John Fultz answered with a method using the hilariously named ...
11
votes
0answers
214 views

What Method options does FindInstance accept?

While answering Trouble getting FindInstance to return multiple results for certain constraints it became clear that for this problem FindInstance would be better ...
10
votes
2answers
224 views

Bags and non-standard evaluation

What can internally be happening here? Is the evaluator just messing with us and going non-standard because it's a Bag? Or am I just not seeing how something like ...
10
votes
1answer
221 views

How can I make FilledCurve smoother?

In How can I generate and randomly assign color to annular sectors? J.M. showed an interesting way to create a sector graphic using FilledCurve. Unfortunately it ...
10
votes
1answer
215 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
179 views

Why is a symbol still found after changing its context?

It seems that we can change the context of symbols: In[1]:= x = 1 Out[1]= 1 In[2]:= Context[x] = "foo`"; But then x is still ...
9
votes
2answers
374 views

Is there a “GrabHand” and “OpenHand” MouseAppearance in Mathematica?

MouseAppearance[Plot[Sin[x], {x, 0, 5}], "LinkHand"] Unfortunately I cannot get a screen grab to show the link hand but it is a cartoon hand with a finger ...
9
votes
1answer
178 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 ...
8
votes
2answers
338 views

How to get a list of available appearance/styles/Methods?

This is a basic question but I haven't found any answer yet :/ Available appearances for Button[] are mentioned in Help, those ...
8
votes
2answers
255 views

What does IndexBy do and how exactly does it work?

I just saw the function IndexBy in the autocomplete suggestions and I was curious to know exactly how it works. Unfortunately, there's no trace of it in the ...
8
votes
1answer
117 views

What's the goal of the Macros` package?

I see in the Mathematica install a Macros` package. In windows the paths is for example: ...
8
votes
1answer
167 views

Possible Method for MatrixExp

Well, probably a hard question, but I think it's better to cry out loud :). I noticed that MatrixExp owns Method option when ...
8
votes
1answer
128 views

Strange behaviour of Internal`InheritedBlock

I was going to post an answer for fast way to replace all zeros in the matrix. I was even quite happy because timings were the same order of magnitude as others. The idea was to overwrite ...
8
votes
0answers
189 views

TableView displays negative numbers incorrectly

I'm trying to substitute TableForm with TableView because TableView is more handy with big data . But on my Mathematica 9.0.1 (ubuntu 14.04_64bit) there is a problem with negative numbers: ...