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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31
votes
2answers
1k views

List of atomic expressions

I was surprised to see Graph objects are atomic. Is there a way (through documentation or programmatically) to find all atomic heads? The ones I know of are: <...
24
votes
4answers
2k views

ReadList problem related to Record type

A simple file reading issue is baffling me here. I am reading a around 200 MB textual file in .dat format. Now the file contains many lines but to phrase my problem ...
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) ...
6
votes
1answer
778 views

Using the symbol I for electrical current [duplicate]

I would like to use the I as a symbol for the electrical current. How can I redefine it, so it is not interpreted as the imaginary unity?
2
votes
2answers
345 views

How to unprotect GeneratingFunction

I'm trying to add custom downvalues for GeneratingFunction, and to do so I thought I just had to Unprotect it. However, that ...
20
votes
1answer
347 views

Why are some option values symbols, other strings?

Is there a rationale, beyond historical accident, why some Mathematica option values are strings, while others are symbols? It seems natural that some value spaces, e.g. named color schemes, are so ...
7
votes
1answer
262 views

A unexpected behaviour of RelationGraph

$Version "10.4.1 for Microsoft Windows (64-bit) (April 11, 2016)" I want to match the based point of VoronoiMesh(...
7
votes
2answers
135 views

Cannot Block Plus

It is customary to use the following idiom to partially evaluate something inside a held expression: ...
4
votes
2answers
228 views

Underflow error General::munfl from E^x instead of Exp[x]

In contrast to earlier versions, Mathematica 11.3 and 12.0 generate lots of underflow errors from my code, e.g. ...
31
votes
3answers
2k views

Why is Plus so much slower than Total?

Why is Plus so much slower than Total for summing lists? ...
18
votes
1answer
666 views

How to define a custom 2/3D graphic primitive like built-in?

There are lots of basic graphic-primitives in Mathematica, such as 2D- primitive: Line[], Circle[], Disk[] and 3D-primitive: ...
16
votes
3answers
765 views

How would I return a random Mathematica command?

I'm doing some metaprogramming. How would I make a Mathematica function that returns a random Mathematica command? Is there a list of command names that I could use ...
11
votes
3answers
586 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 ...
8
votes
1answer
379 views

How to convert formal symbols to standard ones in an expression?

Mathematica generates an expression sometimes using \[Formal] symbols. This is causing a problem with the TeXForm code generated ...
5
votes
0answers
279 views

Organizing Wolfram language symbols with Entity

Here's a word cloud tally of the ~5k System names split at camel humps, with the long tail cropped. What resources are available to organize these terms using the new ...
1
vote
0answers
205 views

Two issues about Underline(d)

From the Help Browser Style["abcd xyz", FontVariations -> {"Underline" -> True}] abcd xyz The text is NOT Underlined, contrary to the online version Also ...
30
votes
2answers
586 views

How to find language changes that were not included in the official change log

A change log is issued when Mathematica has an update, such as: 10.4 10.3 10.2 But for instance the PlotLabels option mentioned in this post is not in the log. ...
26
votes
4answers
998 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 ...
12
votes
2answers
750 views

How to get short definition of all built in Mathematica Functions?

The first post in "Mathematica Weekly Newsletter - Tuesday, December 30, 2014" really attracted my attention as I was always looking for a complete list of built in Mathematica functions with short ...
15
votes
2answers
387 views

Pop-up documentation for “The new function of the day”

The Wolfram Language has more than 5000 built-in functions and constants. ...
9
votes
0answers
319 views

Built-in symbols which are more close to the root/core of Wolfram Language

Seeing the vast scope of science covered by the Wolfram Language (WL) and the large amount of built-in symbols (functions), I am curious to know which built-in symbols are more close to the root of WL,...
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?
15
votes
1answer
217 views

All value types for a symbol?

Robby Villegas here shows a nice way to see all the types associated with a symbol. He sets a symbol, valueTypes, to an explicit list of the values types in ...
11
votes
2answers
393 views

Built-in symbols that support operator form [duplicate]

In version 10 some built-in symbols are updated to support operator form like the Derivative. For example, Select, ...
11
votes
4answers
518 views

When should I use Apply (or Function) and when @@ (or &)?

This is a rather general question, which I fail to answer myself. I guess it is mainly due to my insufficient knowledge of the precise terms. If I understand correctly, the following are equivalent: ...
8
votes
2answers
939 views

How to unprotect a variable in a package

In Mathematica 9, I had the function(s). I apologize for the weak formatting. ...
8
votes
1answer
258 views

Builder pattern for complex objects construction

Intro I was watching "UnRisk-Q Instrument Builder" talk (https://www.youtube.com/watch?v=Xx3goIBpOdE) and those guys use builder pattern to build complex objects like this: ...
7
votes
2answers
368 views

Get name of hidden inbuilt functions (like Ticks drawing)

how do I get the name and definition of a builtin Mathematica functions? For instance, I would like to see how default Tick plotting function is implemented. However, it is not clear where it is and ...
5
votes
2answers
210 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 ...
8
votes
1answer
192 views

What's the purpose of the GeneralUtilities`UnpackOptions?

?? GeneralUtilities`UnpackOptions ...
6
votes
2answers
138 views

How do I make Conjugate behave more consistently?

Sometimes Conjugate distributes. Sometimes it doesn't. Look: ...
5
votes
2answers
167 views

A unexpected behavior in RelationGraph

Bug introduced in 10.2 and fixed in 11.0.1 Firstly we get these idiom ...
5
votes
1answer
212 views

Is there a method to look inside at the internal code of Built-In functions? [duplicate]

How can I look at the code of built-in functions? Is there something like this: LookInsideFunction[SubsetQ] RETURNS ...
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 ...
2
votes
2answers
72 views

Replacing with pattern on built-in symbols?

I have: f[a, b] /. f[x__] -> g[x, 0] // InputForm (* Out: g[a, b, 0] *) Which is what I expect, but when I use a built in symbol instead of ...
1
vote
1answer
442 views

Implementation of Kullback–Leibler divergence in Mathematica: dealing with negative infinity?

I'm trying to implement a function to calculate Kullback-Liebler Divergence but I am running into a problem with complex infinities in my intermediate result. Here is how I have implemented it thus ...
9
votes
1answer
195 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 ...
7
votes
1answer
150 views

How does Internal`PolynomialFunctionQ work?

I found that Internal`PolynomialFunctionQ performs much better than PolynomialQ. Here is a huge random polynomial in 12 ...
7
votes
1answer
349 views

How to define the Bernstein function like the built-in BernsteinBasis?

We know the Bernstein function defined as below: $$B_{n,i}(u)=\binom n i u^i(1-u)^{n-i}$$ And we define $B_{n,i}(u)=0$ when $i<0 $ or $i>n$ In addition, the first derivative of $B_{n,i}(u)$ ...
7
votes
2answers
161 views

Constructing expressions using Sum vs Array[… Plus] vs Plus@@Table[…]

For constructing a sum of terms which are symbolic, I noticed that in addition to ...
5
votes
0answers
55 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 ...
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 ...
4
votes
1answer
134 views

Question about WaitUntil

I have a such function: ...
4
votes
3answers
330 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 ...
3
votes
4answers
967 views

How to obtain the gradient of a function as a function?

The Grad function allows me to get the gradient of a function like this: ...
3
votes
2answers
111 views

What's the difference between 56 and Integer[56]? [duplicate]

I'm trying to grasp how to Wolfram Language uses symbolic expressions for everything. The concept of doing so makes sense to me, but the language doesn't behave how I predict. I understand how ...
3
votes
1answer
98 views

How to replace the symbol n in DifferenceRoot

I'd like to employ another symbol (say alpha or k) instead of n in the following (type of) ...
1
vote
3answers
101 views

Why do atomic objects like 56 have a head if they're supposed to be, well, atomic?

This question follows from this one I made earlier. If you ask for FullForm[4] you will get back 4, and that's fine. ...
1
vote
1answer
686 views

How to list all functions in a package? [duplicate]

I got a package which can be loaded in MMA. The manual for the package does not give demonstrations of all functions/commands. Hoe can i find all the commands in the package?
0
votes
1answer
107 views

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

I was trying to match some polynomials, but this is weird: ...