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....
- 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 ...
- 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]...
- 1,196
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
...
- 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 ...
- 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Leaving my old answer below for historical reference, however as of version 11.2.0 (currently available on Wolfram Cloud and soon to be released as a desktop product) the low-level linear ...
- 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.
<...
- 3,120
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 ...
- 26.8k
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:
...
- 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:
...
- 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 ...
- 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.
- 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]
...
Kuba♦
- 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:
...
- 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}, . . .
...
- 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 ...
Kuba♦
- 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 ...
- 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 ...
- 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 ...
- 45.4k
17
votes
Accepted
What does ImageSize -> 1 -> 1 mean?
Using FullForm, you can see that ImageSize -> 1 -> 1 is the same as ...
- 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 ...
- 1,760
Only top scored, non community-wiki answers of a minimum length are eligible