58 votes

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

Introduction This post is long overdue as I have been repeatedly asked to explain code of mine containing these things. As I see increased use of this construct by others perhaps it is past due also....
user avatar
  • 264k
47 votes

What are some useful, undocumented Mathematica functions?

Sequential With From Daniel Lichtblau's comment there is a new undocumented syntax for With introduced sometime after version ...
40 votes
Accepted

Undocumented use of Integrate: Integrating over regions

Funny you should ask :), it turns out there is an undocumented use of Integrate that one can leverage to integrate over regions. Unfortunately this does not seem to ...
user avatar
  • 32.5k
37 votes

What are some useful, undocumented Mathematica functions?

Internal`PartitionRagged This one has a usage statement! Internal`PartitionRagged[Range[14], {3, 5, 2, 4}] ...
36 votes

What are some useful, undocumented Mathematica functions?

Internal`InheritedBlock What does Internal`InheritedBlock do? Daniel's MathGroup post Strange behaviour of Internal`InheritedBlock How safe is the use of Block ...
36 votes

What are some useful, undocumented Mathematica functions?

System` The default value for the overhang parameter k (3rd argument) in ListCorrelate is ...
36 votes

How to work with Experimental`NumericalFunction?

To create Experimental`NumericalFunction, one needs to evaluate Experimental`CreateNumericalFunction[vars, expr, dims] where <...
35 votes
Accepted

What is the purpose of Internal`LocalizedBlock?

Internal`LocalizedBlock behaves the same as Block, but it can localize non-Symbols (e.g. f[1]...
user avatar
33 votes

How can I work with RawArray?

This is a community wiki answer. Feel free to improve it. Introduction RawArray is an atomic array type that can hold data in any of the following formats: ...
31 votes
Accepted

How to use the iterator in Mathematica

Such functions set up a one-time iterator, i.e. a GeneralUtilities`Iterator. Its functionality may be inspected with ...
user avatar
  • 213k
29 votes
Accepted

How to use Handler functions

So I have a little bit more info, but mostly a learning technique we can test: Init I wanted to see when each of these was called so I made each possible handler (without a previous assignment) just ...
user avatar
  • 45.4k
27 votes
Accepted

How to know the usage of undocumented function like LinearAlgebra`BLAS?

Update Leaving my old answer below for historical reference, however as of version 11.2.0 (currently available on Wolfram Cloud and soon to be released as a desktop product) the low-level linear ...
user avatar
  • 25.1k
27 votes
Accepted

Why is SatisfiabilityCount faster than SatisfiableQ?

SatisfiableQ has three methods: "BDD": converts the expression to a BDD (binary decision diagram), "SAT": uses the Minisat library, "TREE": a branch-and-bound method based on the expression tree. <...
user avatar
27 votes

How to export an MXNet?

It seems the model file in MXNet (checkpoint) is defined by two files: a ".json" file and a ".params" file. The json file contains the definition of the network, and the params file contains the ...
user avatar
27 votes
Accepted

Is Internal`StringToDouble broken in 12.3?

StringToDouble was renamed StringToMReal as part of code cleanup and the addition of several friends: ...
user avatar
  • 13.3k
26 votes

What are some useful, undocumented Mathematica functions?

Properties for SparseArray and InterpolatingFunction objects SparseArray objects can accept ...
26 votes

What are some useful, undocumented Mathematica functions?

Compile`InnerDo This is the one that initially struck me as interesting since I use compiled functions quite a lot. From the documentation of ...
26 votes

What are all the named Mathematica styles?

Version 10 introduced some undocumented functionality that makes it easier to explore the style hierarchy. As usual, "undocumented" === "buyer beware". We start by evaluating: ...
user avatar
  • 67k
26 votes
Accepted

Specifying non-conflicting PlotTheme options

The details of the styles associated with various themes can be accessed using the function ResolvePlotThemes in the Charting ...
user avatar
  • 348k
26 votes
Accepted

How to get old message formatting in version 11?

We can get old-style messages using Internal`$MessageMenu = False Needless to say, this is unsupported and undocumented functionality.
user avatar
  • 224k
23 votes

Bug with iterated With: Referring to function arguments invalidates previous definitions

A long comment: Automatic renaming again: ClearAll[F]; F[x_] := Hold[With[{a = x}, {b = x}, a]]; F[0] ...
user avatar
  • 132k
23 votes
Accepted

How can I determine the type of a packed array?

We can use one of several ways. First, let us create some test data: ...
user avatar
  • 224k
21 votes
Accepted

In 10.1.0 BenchmarkPlot doesn't work?

In addition to the error messages quoted in the question the line returns: GeneralUtilities`Benchmarking`PackagePrivate`plot[ IndexBy[{{{16, 9.37132*10^-6}, . . . ...
user avatar
  • 264k
21 votes
Accepted

What is FrontEnd`AttachedCell?

Intro One day I was playing with Developer` package and found DateSetter which uses some kind of floating elements that I found ...
user avatar
  • 132k
20 votes

What are some useful, undocumented Mathematica functions?

System`Private`*Entry* functions Since version 10.0 System`Private`SetNoEntry and ...
20 votes
Accepted

Why does setting SyntaxInformation add a definition to DefaultValues

In my view, the Mathematica front end would have needed a complete rewrite a long time ago to be in a shape where it can compete with modern UI's. Looking at MATLAB, it's clear that you always find ...
user avatar
  • 111k
19 votes
Accepted

What pseudo-random number generators are available to Mathematica users?

No, there are no more built-in generators. In this case, the SeedRandom::nogen message can be regarded as definitive. The list it prints is not predefined, but a ...
user avatar
  • 25.1k
19 votes

Language`* documentation project

Language`*Mutation* First seen here, implemented by Taliesin Beynon What do they do? The only functions I really know about in this bunch are the ...
user avatar
  • 45.4k
17 votes
Accepted

What does ImageSize -> 1 -> 1 mean?

Using FullForm, you can see that ImageSize -> 1 -> 1 is the same as ...
user avatar
  • 86.8k
17 votes

What are the main differences between RawArray and PackedArray?

Here goes my conjecture but I would welcome any opinion or clarification by people in the know. PackedArray stores data in a computation-efficient way. It still ...
user avatar
  • 1,760

Only top scored, non community-wiki answers of a minimum length are eligible