# Questions tagged [undocumented]

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

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### Log scale for ListContourPlot when the axes have different orders of magnitude

I am trying to plot a data set (download here) in Mathematica (it's 3.9 MB and I wasn't sure how to best share it) which I then want to visualize with ...
325 views

### Please explain this syntax: GaborWavelet[6][“FourierFactor”]

I've been using Mathematica for some years, yet I'm befuddled by this statement: GaborWavelet[6]["FourierFactor"] It appears to give the center frequency ...
191 views

### BarLegend ticks distorted in MatrixPlot

As shown in many threads here (this, this, ...), Ticks is a valid option of BarLegend. But it doesn't seem to work well in this ...
167 views

### ExperimentalCreateNumericalFunction

When working with a Compile function I can specify if a given argument is a matrix, a vector or a scalar. For instance, something like: ...
116 views

### A Curiosity: What is DispatchQ?

As shown below, my autofill in Mathematica showed an interesting function: DispatchQ. Yet, it does not appear in the Mathematica Documentation Center, a search for ...
75 views

### Why are some symbols recognized by Mathematica but nowhere in the documentation? [duplicate]

I was trying to calculate a Groebner basis for a given set of polynomials, and I did it successfully. But I wanted to calculate the conversion matrix between the original basis and the Groebner basis....
93 views

### Implicit Riccati Equation Solver (to find the anti-stabilizing solution)

I've found that the latest MATLAB icare() solver includes the possibility to find also the anti-stabilizing solution of the Riccati equation. I haven't found a ...
59 views

### What does the PerformanceGoal option of FindMinimum do?

FindFit and FindMinimum both have a PerformanceGoal option. It is not documented. What does ...
104 views

### In search of lost time: Mathematica keyboard shortcuts

I am wondering about all the shortcuts that there are in Mma, besides the documented ones in https://reference.wolfram.com/language/tutorial/KeyboardShortcutListing.html. Are there any undocumented ...
119 views

### Is AlgebraicRulesData magical?

I am trying to understand what AlgebraicRules is all about in the answer to this question. It apparently returns an ...
200 views

### What does ReduceFreeVariables really do? And can we rely on it?

Very frequently, in answers on this site, the undocumented function ReduceFreeVariables comes up in the context of generating a list of variables inside an ...
86 views

### How to make my custom neural layer only apply noise during training (similar to how DropoutLayer behaves)?

Utilizing some undocumented Mathematica functionality, I implemented it like this: ...
137 views

### How to author a workflow?

I find the workflow refpages in the doc center very helpful, and I'd like to make some of my own: Workflows seem to be notebooks of "Text" and ...
85 views

### Is it possible to get current thickness for every Line, Polygon, Circle object in a plot?

When exporting Mathematica graphics to raster formats with high resolution the common problem is that thickness for such objects as Line, ...
133 views

### Why does setting SyntaxInformation add a definition to DefaultValues

Before setting any definitions to the symbol f, the DefaultValues of f is empty: ...
54 views

### How to extend the DefaultDuration of Manipulate[] when it has Bookmarks?

How to extend the DefaultDuration of Manipulate[x,{x,0,1},Bookmarks->{"beginning":>(x=0),"end":>(x=1)}] to 20 ...
111 views

### Is it possible to make listable ExperimentalNumericalFunction?

I have been playing a bit with the undocumented function ExperimentalCreateNumericalFunction and I wanted to know if somebody found a way to make generated ...
128 views

### Status of Streaming package

I see the Streaming package mentioned in this question How to use Streaming package in v11.1? with advice on getting it working in V11.1. I've failed to get either the built-in version or the patch ...
108 views

### Problem with “MediaTools” in Mathematica 12

I asked here for a solution how single video images can be extracted very fast from avi files. Piotr Wendykier gave a solution for Mathematica 11.3. Now I'm using Mathematica 12 and his solution ...
64 views

### TemporalDiscretization in MethodOfLines

When solving ODE's one can use options like MaxStepFraction to control the number of grid points. When solving PDE's ...
84 views

### How to vectorize this nonlinear ODE system for NDSolve?

I learned a long time ago that NDSolve can often be sped up by vectorizing systems of equations. I've got a problem now that seems ideal for this approach, but I ...
138 views

I would like to calculate the Peano-Baker series with mathematica, namely an integral expansion to approximate the state transition matrix: Say I have a matrix $A(t)$ and I want to calculate: $\Phi(... 1answer 120 views ### Can we construct our own NDSolveStateData? NDSolve can be broken into three stages: NDSolveProcessEquations processes the equations and sets up an NDSolveStateData ... 1answer 163 views ### Can't make more than 249 InternalBags in a Table I need a lot of InternalBags so I made them with Table. It works fine for 249 or fewer Bags... 0answers 117 views ### How to modify NDSolveStateData without crashing the kernel? Probably a hard question, but it's better to cry out loud. Reminded by Chris K, I noticed my fix function has been broken since v11.3. After some checking, I ... 1answer 83 views ### MatrixConditionNumber does not work in version 12.0 A = {{1., 0.}, {0., 2.}}; LinearAlgebraMatrixConditionNumber[A] 1answer 222 views ### What is the most reliable way to find a particular function? I learned there're built-in functions which is not documentedćfrom this question. After this , I tried looking for something which is usable for me,then noticed that with ... 0answers 107 views ### Reverse Engineering of MMA Classify[] Output? Update: as @AntonAntoniv rightly noticed in his comment the case of DecisionTree is already discussed. Now it would be great to also have an equivalent answer for LogisticRegression. MMA is really ... 1answer 49 views ### Can I reimplement something like TogglerBox? As a purely academic exercise can I make a box structure that'll toggle between two views when clicked and that doesn't ever depend on Dynamic or ... 1answer 109 views ### How to not show line mesh elements Let's say I make a mesh from a collection of random points: SeedRandom[1234] points = RandomReal[1, {20, 2}]; mesh = VoronoiMesh[points] For the purposes of my ... 0answers 70 views ### Evaluating Internal$VideoEncodings gives a strange message

When calling Internal\$VideoEncodings to check available video codecs on my pc, Mathematica_11.3 gives a message: ...
44 views

### Why does the kernel strip \< and \> from strings [duplicate]

The FE always passes strings to the kernel that look like: "\"\<asdasd\>\"" And the \< and > get pruned out. We can simulate this for ourselves with: <...
124 views

### How can I see all FE nine-patch bitmaps?

The FE stores a bunch of little nine-patch images in the layout that govern the appearance of much of Mathematica. These things are incredibly useful to have as they may be used to give a clean ...
46 views

### Second argument Run[]

Run officially takes only one argument. I encountered code with Run[command, "Text"], is this a mistake or is the second argument meaningful? If so what does it do? ...
34 views

### Method option of function MatrixRank

By running ??MatrixRank, I see that it has an optional argument named Method. However, this argument is not in the ...
104 views

### Making an Association-like interface for HashTable

SystemUtilitiesHashTable is conceptually a lot like an Association but it has the pretty phenomenal (for Mathematica) property ...
71 views

### Custom Property interface on my own objects

I know I can use the Property interface for things like Graph but I want to use it for all of my objects. This includes: ...
79 views

### Custom conversion rules in UnitConvert

I want to make UnitConvert operate on custom units with special rules. For instance, I would like to be able to convert between ...
34 views

### Create a ProcessObject for a process not made with StartProcess

I am launching and linking to Mathematica from an external process and would like to be able to create a ProcessObject for the launching process that will support <...
49 views

### How to make custom attached menubars? [duplicate]

I would like to understand how to build an attached menubar. For example, Image has the following bar - an attached cell that arises when clicked on: ...
174 views

### Others problems with GraphicsPolygonUtilsPolygonCombine

As a continuation of this question, writing: ...
240 views

### Problem with GraphicsPolygonUtilsPolygonCombine

Writing: Normal@ParametricPlot[{x, x^2 t}, {x, 0, 2}, {t, 0, 1}] /. p : {__Polygon} :> GraphicsPolygonUtilsPolygonCombine[p] I get: but if I write: ...
141 views

### Undocumented GraphComputationGraphProduct usage

According to Mathworld there is an undocumented function GraphComputationGraphProduct[G1, G2, "Cartesian"] To compute the cartesian graph product. Now in ...
35 views

### Get all built-in image files for styling buttons and panels

Mathematica makes use of nine-patch images in styling its resizable interfaces like Panel and Button. Nicer than remaking new ...
367 views

### What happened to SequenceLimit?

In older versions of Mathematica, there was a function called SequenceLimit that allowed taking the limit of a numerical sequence. It is useful for speeding up the ...
91 views

### LanguageExpressionStore and ParallelMap

Is there a way to access NewExpressionStore from within a parallelized calculation? I have tried variations of ...
65 views

### Special forms for autocompletion strings

Szabolcs has previously dug up a very useful tool to make custom autocompletions. Here's that in action: ...
117 views

### Implementing jacknife method

I need to use a jacknife method in order to find the standard deviation of my data. Howvere, I realise there's no built-in fuction (or maybe I couldn't find it), not even a general bootstrap method. ...