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Questions tagged [built-in-symbols]

Questions related to handling built-in symbols and functions, for example why they behave a certain (possibly unexpected) way.

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4
votes
3answers
338 views

Faster trace of product of two matrices

I noticed that for the computation of the trace of a product of two matrices, using Tr[Dot[A,B]] is a little inefficient. Dot ...
9
votes
1answer
248 views

Table of precedence values for all System` symbols

Has anyone created a table listing the precedences for all symbols? Also, it would be nice if there were a function that for a given precedence value or interval, returned all the symbols with that ...
1
vote
0answers
51 views

Wigner-D in MMA

Can some nice MMA fellow explain to me why buit-in Wigner-D function is defined as $D_{mm'}^{J} = e^{i(\phi m+ \gamma m')} d_{mm'}^{j}(\theta)$ against the convention, used by most people on Earth, ...
1
vote
1answer
151 views

How to prevent simplification from Times to Power?

By default, Mathematica simplifies Times[f[x],f[x]] as Power[f[x],2]. In most cases it's fine, but I happen to have a code where ...
4
votes
1answer
65 views

What does $UseTextSearchQ do?

Mathematica 11.2 features a new built-in symbol in the Global` context: Global`$UseTextSearchQ What does it do, and how do I ...
9
votes
1answer
197 views

1 is not the SameQ as Null, but why might 1 be Equal to Null?

The command SameQ[1, Null] returns False which is what I would expect, but the command ...
2
votes
1answer
172 views

Implement edge contraction function which respects vertex weights

It seems that built-in EdgeContract function doesn't work properly with weighted graphs, to be more precise, I mean that if I'm going to contract edge $e$ which ...
3
votes
4answers
199 views

What is the inverse of the Position function?

What is the inverse of the Position? I have an array which contains the positions of elements and I want a function which returns an List which contains 1 where ...
2
votes
1answer
119 views

How does one plot an oblique/slanted cylinder within the plot range?

A Cylinder does not seem to have an option to make it oblique. A Tube has an oblique center but does not seem to have an option to make the end caps oblique. One could plot a cylinder or tube that ...
0
votes
1answer
53 views

Why the export the Graphics or Image to local file [closed]

I note the Put cannot export the Graphics or Image,I mean this code will be failure. ...
5
votes
4answers
322 views

Mean of a list of lists (vector) with missing values

I understand, from Calculating the mean of a list with NaN values, that one can preserve structured data with missing values, and still calculate a mean, using ...
7
votes
1answer
350 views

Geometry computations add-on for Mathematica?

I came across the problem of calculating the circumcenters of triangles symbolically within another algorithm (as well as possibly doing other similar geometry computations). I was hoping Mathematica ...
11
votes
3answers
605 views

Is it safe to Unprotect everything? What are the implications?

What is the reason for built-in symbols to be Protected? What happens if I Unprotect built-ins and add my own ...
1
vote
1answer
132 views

Having trouble defining a function with head Superscript

I wish to define a function in the following form, ...
5
votes
1answer
78 views

Unexpected result of Clip

A simple question. Here Clip works as documented: Clip[0.5, {0, 0}, {0,1}] (* 1 *) Values larger than 0 are replaced with ...
24
votes
2answers
1k views

List of symbols without built-in meaning

Is there a list of all symbols with special display forms but no built-in meaning? That is, operators that are described in the tutorial Operators without Built-in Meanings?
4
votes
1answer
97 views

Internal function overload when calling ReadString on a fresh kernel

Problem description: I am capturing all FE messages to redirect them to my own window while blocking them from showing in the evaluation notebook using this method by rcollyer. It works great, but I ...
31
votes
3answers
2k views

Why is Plus so much slower than Total?

Why is Plus so much slower than Total for summing lists? ...
5
votes
0answers
57 views

Why ReadList ignores NullRecords for Number?

When thinking on this recent question the immediately obvious solution which came to my mind was to use ReadList with options ...
2
votes
1answer
133 views

Changing operator precedence

Is there a way to change operator precedence for built-in symbols? I'd like \[TensorProduct] (which I redefine to ...
26
votes
4answers
1k views

What's purpose of the new function BinarySerialize?

11.1 introduced a new function BinarySerialize, but I don't know what it can do better than the traditional method.Its behavior is very similar to ...
1
vote
0answers
77 views

Controlling precision/accuracy inside built-in commands

Some functions (such as Erf) appear to use NIntegrate internally. In such cases, is there a way to control such options of ...
4
votes
2answers
248 views

NetModel's cache in which folder?

NetModel will produce a big cache file after you use it first time. ...
1
vote
0answers
51 views

How to run the command 'Distribute' on large product of multivariable polynomials without simplifying it

I am new to Mathematica, so pardon if question is trivial. I am trying to expand (i.e multiply out the factors) an polynomial expression $d$, with many factors, obtained as a result of taking ...
3
votes
1answer
88 views

What is the point of ActiveClassification?

I must be missing something here - it seems that the first argument to ActiveClassification is your target function, but if you already know that function then why ...
1
vote
1answer
92 views

What does the return value of Internal`ArgumentCountRegistry mean?

Internal`ArgumentCountRegistry sometimes will give a value about some function.Such as ...
0
votes
0answers
55 views

built-in functions with one argument

I want to find the (NumericFunction) built-in functions that take exactly one document. ...
1
vote
1answer
87 views

Unexpected behavior of ForAll

Resolve[ForAll[n,Element[n,Integers],!IntegerQ[Sqrt[n^2-7 n-1]]]] True But as I know,when the n is $17$,...
4
votes
1answer
74 views

Inverse of CharacterName [duplicate]

Is there an inverse function to CharacterName? For example, CharacterName["ε"] gives ...
1
vote
0answers
55 views

How to convert `LogTicks[0, 2][[1, 2]]` to a regular number

I want to convert the $10^i$ tick labels generated by LogTicks of the CustomTicks package to regular numbers. The first tick ...
2
votes
0answers
61 views

Built-in functions for Homotopy group

Does Mathematica have built-in functions for Homotopy group, for example for computing $$\pi_n(S^m)=?$$ or more generally $n$-th homotopy group, $$\pi_n(X)=?$$ for some $X$. (I search, but I could ...
2
votes
1answer
228 views

Tag protected error for Grad despite using Unprotect[Grad]? [duplicate]

I've defined an upvalue grade[k,m], where k is an integer and m is a matrix, and have defined a number of overrides for this type in the normal Mathematica namespace (...
3
votes
0answers
73 views

Use of ContainsAny in EntityClass

The documentation page for EntityClass states that Property values in implicitly defined entity classes may make use of Quantity (and intervals of Quantity) for ...
8
votes
1answer
193 views

What's the purpose of the GeneralUtilities`UnpackOptions?

?? GeneralUtilities`UnpackOptions ...
4
votes
1answer
135 views

Question about WaitUntil

I have a such function: ...
5
votes
1answer
136 views

What is the purpose of MatchLocalNameQ?

I found a kernel function which is undocument MatchLocalNameQ.But I don't know the purpose of it. ...
5
votes
2answers
213 views

How to find all function which cannot be ToExpression?

If you use ToExpression directly like this ToExpression /@ Names["*`*"] You will get a chunk error information.I try to ...
7
votes
2answers
239 views

Timeline overview of implemented Mathematica functions

With WolframLanguageData[{"ListLogPlot", "Plot", "ColorNegate"}, "Timeline"] one gets information at what time and version a certain function was implemented: ...
5
votes
1answer
181 views

What is the purpose of GraphComputation`MeshGraph?

When I use GeneralUtilities`PrintDefinitions to print its definition,I will get this information: So I think this function can convert a ...
5
votes
1answer
95 views

Unexpected behavior of ComplexityFunction

As far as I know, the complexity must be a positive value. But I get such example: ...
0
votes
0answers
69 views

Is it possible to define a new built-in function in Mathematica? [duplicate]

Say I want to define a function to do integration by part, is it possible to define it as a new built-in function in Mathematica, so that I don't need to define it every time I want to use it?
-1
votes
2answers
66 views

Unexpected behaviour of ColorFunction

...
4
votes
3answers
150 views

How do I type the independence symbol in Mathematica?

I know this seems to be a really stupid question, but I can't find a way to type the independent symbol. I found how to write the \[UpTee] but it isn't the same. ...
2
votes
1answer
277 views

Define Tilde as a postfix operator

I have read a lot of posts in this forum on defining infix symbols like CircleDot and Tilde. The Help pages say ...
6
votes
1answer
197 views

How to judge the function is kernel function or not in program method?

I found the behavoir have changed. All symbol in System` is kernel funtion(include those your custom funtion) ...
12
votes
1answer
263 views

Why isn't Orderless an Attribute of And?

In standard logic And is a commutative operator. Still, in Mathematica, And doesn't have the ...
2
votes
1answer
52 views

Understanding the behaviour of CrossingDetect on lists

Consider the first example in the documentation of CrossingDetect: CrossingDetect[{4, 0, 1, -2, 1, -2, -3, -1, 3}] // Normal ...
2
votes
0answers
57 views

How would you rewrite these procedurally coded internal routines in functional form?

I came across the following two internal functions SimplifyDump`AbsToSign and SimplifyDump`SignToAbs that have been written ...
0
votes
1answer
109 views

`Plus` wrongly applies `OneIdentity` to eradicate itself in `Plus[Power[_, 2] ..]`, unreproducible

I was trying to match some polynomials, but this is weird: ...
6
votes
2answers
143 views

How do I make Conjugate behave more consistently?

Sometimes Conjugate distributes. Sometimes it doesn't. Look: ...