Questions tagged [undocumented]
Questions on undocumented functionality of Mathematica. Note that such functions might be subject to change without notice in future versions.
275
questions
17
votes
1answer
579 views
Is Internal`StringToDouble broken in 12.3?
I believe Internal`StringToDouble was the only way to fast convert string into numbers. Now in V12.3 it was removed:
Internal`StringToDouble["1"]
...
2
votes
1answer
62 views
How to set MaxStepSize for the case of two variables
The option MaxStepSize permits to manually set the step size of the integration in NDSolve and similar functions.
How do I set ...
0
votes
1answer
45 views
TemplateEvaluate, TemplateUnevaluated, and TemplateVerbatim [Undocumented] - What do you know?
Let's discuss some undocumented Template-related functionality. Specifically, what do you know about TemplateEvaluate, ...
5
votes
1answer
150 views
NDSolveValue and pdepe of MATLAB disagree under spherical coordinates
Assuming there is a spherical activated carbon particle, the concentration outside the grain is 200 (C[t,ri] == 200), that ...
4
votes
1answer
74 views
Turning off automatic hyperlinks
Recently (I only noticed in V12.2), website URLs, such as https://www.wolfram.com, became active in text cells in notebooks. The "hot" nature makes the links hard to edit, since any click ...
5
votes
0answers
44 views
How to revert behavior of SeriesData to pre 12.1
In Mathematica 12.0 and earlier,
SeriesData[x, 0, {1/u + Log[x/y]}, 0, 3, 1]
used to preserve its list of expressions in the form it was given.
Now, in ...
5
votes
1answer
140 views
Property “Centroid” of result from ConvexHullMesh[] can not be extracted
As the title describes, specifically, simple code below
ConvexHullMesh[RandomReal[1, {10, 2}]]["Centroid"]
returns an error in V. 12.2, but it worked in ...
0
votes
1answer
60 views
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 ...
8
votes
1answer
345 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 ...
9
votes
2answers
231 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 ...
2
votes
1answer
184 views
Experimental`CreateNumericalFunction
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:
...
5
votes
0answers
120 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 ...
3
votes
0answers
83 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....
6
votes
1answer
117 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 ...
5
votes
0answers
60 views
What does the PerformanceGoal option of FindMinimum do?
FindFit and FindMinimum both have a PerformanceGoal option. It is not documented. What does ...
4
votes
1answer
133 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 ...
7
votes
1answer
122 views
Is AlgebraicRulesData magical?
I am trying to understand what AlgebraicRules is all about in the answer to this question. It apparently returns an ...
14
votes
1answer
221 views
What does Reduce`FreeVariables really do? And can we rely on it?
Very frequently, in answers on this site, the undocumented function Reduce`FreeVariables comes up in the context of generating a list of variables inside an ...
1
vote
0answers
92 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:
...
5
votes
1answer
159 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 ...
4
votes
1answer
96 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, ...
17
votes
1answer
148 views
Why does setting SyntaxInformation add a definition to DefaultValues
Before setting any definitions to the symbol f, the DefaultValues of f is empty:
...
5
votes
1answer
68 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 ...
6
votes
1answer
128 views
Is it possible to make listable Experimental`NumericalFunction?
I have been playing a bit with the undocumented function
Experimental`CreateNumericalFunction
and I wanted to know if somebody found a way to make generated ...
5
votes
0answers
135 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 ...
1
vote
1answer
115 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 ...
4
votes
1answer
99 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 ...
6
votes
1answer
104 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 ...
3
votes
1answer
193 views
Implementing the Peano-Baker Series with Mathematica
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:
$\Phi(...
8
votes
1answer
145 views
Can we construct our own NDSolve`StateData?
NDSolve can be broken into three stages:
NDSolve`ProcessEquations processes the equations and sets up an NDSolve`StateData ...
13
votes
1answer
169 views
Can't make more than 249 Internal`Bags in a Table
I need a lot of Internal`Bags so I made them with Table. It works fine for 249 or fewer Bags...
10
votes
0answers
136 views
How to modify NDSolve`StateData without crashing the kernel?
Probably a hard question, but it's better to cry out loud.
Reminded by Chris K, I noticed my fix function has been broken since v11.3. After some checking, I ...
5
votes
1answer
112 views
MatrixConditionNumber does not work in version 12.0
A = {{1., 0.}, {0., 2.}};
LinearAlgebra`MatrixConditionNumber[A]
3
votes
1answer
223 views
What is the most reliable way to find a particular function?
I learned there're built-in functions which is not documented from this question.
After this , I tried looking for something which is usable for me,then noticed that with ...
5
votes
0answers
114 views
Reverse Engineering of MMA `Classify[]` Output?
Update: as @AntonAntoniv rightly noticed in his comment the case of DecisionTree is already discussed. Now it would be great to also have an equivalent answer for LogisticRegression.
MMA is really ...
7
votes
1answer
54 views
Can I reimplement something like TogglerBox?
As a purely academic exercise can I make a box structure that'll toggle between two views when clicked and that doesn't ever depend on Dynamic or ...
5
votes
1answer
133 views
How to not show line mesh elements
Let's say I make a mesh from a collection of random points:
SeedRandom[1234]
points = RandomReal[1, {20, 2}];
mesh = VoronoiMesh[points]
For the purposes of my ...
0
votes
0answers
72 views
Evaluating Internal`$VideoEncodings gives a strange message
When calling Internal`$VideoEncodings to check available video codecs on my pc, Mathematica_11.3 gives a message:
...
2
votes
0answers
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:
<...
5
votes
1answer
129 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 ...
0
votes
0answers
48 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? ...
0
votes
0answers
38 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 ...
5
votes
1answer
116 views
Making an Association-like interface for HashTable
System`Utilities`HashTable is conceptually a lot like an Association but it has the pretty phenomenal (for Mathematica) property ...
7
votes
1answer
83 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:
...
3
votes
1answer
97 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 ...
2
votes
0answers
35 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 <...
3
votes
0answers
52 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:
...
4
votes
1answer
187 views
Others problems with Graphics`PolygonUtils`PolygonCombine
As a continuation of this question, writing:
...
8
votes
2answers
248 views
Problem with Graphics`PolygonUtils`PolygonCombine
Writing:
Normal@ParametricPlot[{x, x^2 t}, {x, 0, 2}, {t, 0, 1}] /.
p : {__Polygon} :> Graphics`PolygonUtils`PolygonCombine[p]
I get:
but if I write:
...
6
votes
1answer
165 views
Undocumented GraphComputation`GraphProduct usage
According to Mathworld there is an undocumented function
GraphComputation`GraphProduct[G1, G2, "Cartesian"]
To compute the cartesian graph product.
Now in ...
