Questions tagged [built-in-symbols]
Questions related to handling built-in symbols and functions, for example why they behave a certain (possibly unexpected) way.
201
questions
0
votes
0answers
61 views
Div of function evaluates to zero but should be a DiracDelta. How to solve? [closed]
When I attempt to take the divergence of the function $f(r, \theta, \psi) = \hat{r}/r^2$, Mathematica returns zero even though we know mathematically that the answer should be $4\pi \delta(\vec{r})$. ...
4
votes
1answer
261 views
Largest k such that p^k divides n
(Here all variables are integer.)
Is there a built-in function f[n,p] such that
f[n,p] = largest k such that p^k divides n
For ...
1
vote
1answer
72 views
Can I tell whether a symbol is build-in (part of the System` library)?
I'd like a function that checks whether a symbol is a predefined part of the language or not. More generally, it might check whether it's part of a given package.
...
3
votes
2answers
84 views
Built-in functions on the LHS won't pattern-match
I have this pattern-matching problem:
F[X_,myminus[X_]]:=0
F[1,myminus[1]]
Works.
...
7
votes
4answers
351 views
AnyTrue is too good (compared to MemberQ)
Let L be a list of integers, and ⓝ denote an explicit integer.
I've thought the most natural way to tell whether ⓝ belongs to L is
In[1] MemberQ[L, ⓝ]
But there ...
2
votes
0answers
42 views
Definition of large expression - makes PC freezed
In[1] A=Range[10^4];?A
Out[1] (* definition of A*)
It works for 10^4. But if I increase the number to 10^6
...
2
votes
1answer
65 views
Construct really identical function (the same as Length)
In[1] Length[Unevaluated[1 + 1 + 1 + 1]]
Out[1] 4
Q1) Can we construct a function named f, such that ...
0
votes
0answers
39 views
Check an input matrix M contains any nonzero diagonal matrix element or not
Is there a way to easily check an input matrix M contains any nonzero diagonal matrix element or not?
For example,
if the M contains any nonzero diagonal matrix element, Output: True.
if the M ...
2
votes
2answers
98 views
Get list of special characters
I recently found that \[Gradient] and \[InlinePart] both expand (contract) to special symbols in MMA.
So far as I can tell (see ...
1
vote
0answers
72 views
Is there a function in Mathematica to combine/decompose sinusoids? [closed]
Lets say I have some combination of an arbitrary number of sinusoids with potentially varying magnitudes, phase angles and frequencies that I would like to compose into a singular sinusoid, is there a ...
0
votes
0answers
45 views
How to reconstruct a complicated built-in function (e.g. for modification or use in a version that does not have it yet) [duplicate]
Is it possible to extract the definitions for a built-in function to reconstruct a similar user defined function. This would be useful to port new mathematica functionality to older versions or to ...
8
votes
1answer
452 views
very simple but unexpected aspect of Function[ ]
I've always thought
(2#+1)&
and
Function[x,2x+1]
are interchangeable in common sense. But,
...
0
votes
0answers
48 views
0
votes
0answers
45 views
What could go wrong in redefining Power to act on functions?
Inspired by a tweet (from a locked account, unfortunately, so I can't link it), we can get notation like $\cos^2(x)$ to work in Mathematica in general:
...
1
vote
1answer
54 views
How to define distributivity of CenterDot on bras and kets
I am working on a code for a coupled quantum harmonic oscillator and found myself in a hiccup when trying to evaluate the inner product of linear combinations of bras and kets. I have initially ...
3
votes
1answer
71 views
16
votes
1answer
266 views
Head[x] vs x[[0]]
Can we say Head[x] and x[[0]] are identical ?
In mathematica manual I could find : 'The head is the part with index 0'
But I am not sure whether Head[x] are x[[0]] are really interchangeable in any ...
2
votes
2answers
63 views
A condition for the given point to be included in the domain?
If we have two domains, it is possible to check whether one domain is inside another domain:
...
3
votes
2answers
95 views
A condition for one domain to be included in another domain?
Consider two domains:
domain1 = Rectangle[{-2.5, -2.5}, {2.5, 2.5}];
domain2[R_] := Disk[{0, 0}, R]
I would like to check whether the second domain is completely ...
2
votes
1answer
82 views
How to find the area of circle inside the rectangle?
Consider a circle located at the origin
circ[R_] := Circle[{0,0},R]
and an arbitrary rectangle
...
0
votes
0answers
48 views
Dot Product doesn't behave like normal function
I am trying to slightly modify the Dot function by treating it like a usual function, but soon I notice something weird about it.
Suppose there is a set ...
5
votes
1answer
64 views
Counting the number of edges between two graph partitions
Consider the following:
g = RandomGraph[WattsStrogatzGraphDistribution[1000, 0.1, 5]]
comm = FindGraphPartition[g, 2];
CommunityGraphPlot[g, comm]
...
2
votes
1answer
119 views
How &@ and &/@works?
I have the following expression:
(Join[#, Reverse[#, {2}]] &@Partition[#, 2, 1, 1]) & /@ Vec
(* where: *)
Vec={{2,0},{1,1},{0,2}},
but I am not sure how ...
2
votes
3answers
360 views
Compare all elements of a set with a specific number and return 1 or 0
Say I generate a set of 20 random numbers by x=RandomReal[{0, 1}, 20], I want to compare every element of x with 0.4. If it is less than or equal to 0.4, then return 1; if it is greater than 0.4, then ...
0
votes
0answers
52 views
Avoiding Tables, Do and other loop construction
In my work I have a lot of cases, where I should calculate non-listable functions for a quite large number of points. To be more concrete, consider first listable function ...
1
vote
0answers
77 views
How to figure out syntax for symbols?
I'm new to Mathematica and am having a hard time figuring out how to type certain symbols when I read the documentation.
For example, in https://reference.wolfram.com/language/ref/...
16
votes
3answers
968 views
Which function names have been re-purposed in Mathematica after being deprecated?
I have just learned about the new function Splice from this answer. It turns out that this function used to have a completely different usage! (See below.)
To me, ...
11
votes
1answer
463 views
Finding year that MMA functions were introduced via programmatic calls in the Wolfram Language [duplicate]
Is there a way to find the year that MMA functions were introduced via programmatic calls in the Wolfram Language? I would like to be able to create and manipulate such a list or dataset.
4
votes
0answers
41 views
What built-in functions have bad time/space complexity and their alternatives?
It's surprising that Join is $\mathcal{O}(n)$ (due to copy) while I've been using it as a convenient way to join lists together. It also reminds me of suggestions ...
3
votes
1answer
104 views
How can I prevent TabView from resetting the current tab?
This is a simplification of a problem that has arisen in a project regarding Euclidean activities for verifying proportions via operations
on pairs of magnitudes. In the project, the LocatorPane is ...
5
votes
2answers
107 views
Customized priority function in DataStructure["PriorityQueue"]?
I'm using Mathematica 12.1. The documentation for DataStructure["PriorityQueue"] claims that,
... the highest-priority element is always returned.
The ...
1
vote
1answer
71 views
Define trace-like function (e.g. cyclically invariant) involving operators without built-in meaning
I am interested in defining a function, say $\mathrm{Tra}$, that imply operators without build-in meaning, say it involves products with the $\cdot$ (Esc . Esc), ...
3
votes
2answers
59 views
Define the behavior of operators without built-in meaning
I need an operation $\tilde{}$ that lifts another operation (for example, the sum, but this does not have to be limited to real numbers) in the sense that $\widetilde{ (x \oplus y)} = \tilde x + \...
0
votes
1answer
28 views
What is the general behavior of the "enter" character, and why does the specific behavior differ in these four situations?
I am trying to understand the exact behavior of the "enter" character in Mathematica. (I am not even sure what to call it: perhaps it is really the carriage return or newline character, which is input ...
3
votes
1answer
157 views
How to get information from all built-in Mathematica functions in order to create a Kotlin library like the Wolfram Client Library for Python?
I'd like to use (if this already exists) or create a library to use Mathematica together with Kotlin (or Java) (not JLink, please see below).
We already have this very useful implementation for ...
3
votes
0answers
91 views
PowerModList anomaly
This post is related to Not comprehending PowerMod. Here the issue is that PowerModList, in v. 12.1 finds no cube roots of 1 Mod 10^60 - 1:
...
2
votes
0answers
59 views
Who Defines Symbol \$MySource
When I start up a fresh executing Mathematica on my MacOS system and I open a Notebook file there is always one symbol defined in the Global context. This symbol is \$MySource and it points (via a ...
13
votes
2answers
588 views
Looping through all functions defined in Mathematica
Is there a way to loop through all the Functions (Elementary and Special functions) that exist in Mathematica?
I want to construct a table of some identities and maybe I can discover something ...
2
votes
0answers
67 views
How to override a built-in Mathematica function using its old version?
How can we override a Mathematica built-in function using itself in the definition?
For example, the DiracDelta function is not defined for complex numbers like:
<...
2
votes
0answers
49 views
How to Return All Mathematica Functions in a Domain
We know that Names["System*"] and WolframLanguageData[] both return the list of all System or "native" functions.
Is there a ...
6
votes
1answer
90 views
What is the meaning of "Introduced in ..." and "Updated in ..."?
I am looking at the documentation of a Mathematica function and at the bottom it says Introduced in 1988 (1.0) | Updated in 1996 (3.0).
What exactly does this ...
2
votes
1answer
64 views
About AbsoluteCorrelation
In my understanding, "the absolute correlation" is not such a common expression. Can anyone kindly explain the significance of the built-in symbol ...
1
vote
2answers
310 views
Semi-direct product and crossed product symbols
Does Mathematica have any symbols for the semi-direct product $\rtimes$ (or $\ltimes$) and the crossed product $\bowtie$? I have looked at the lists containing all symbols and couldn't find it there. ...
0
votes
0answers
39 views
After execution of simple list manipulation every expression turns dark blue and nothing is defined - how to debug
This question is related to this one in the sense that it uses the code from there.
What happens is best illustrated in the video here. When I run (* part 1 *) ...
4
votes
1answer
693 views
Wrap angle to [0,2pi[
Is there any built-in Mathematica function that wraps any angle in rad to the $[0,2\pi]$ domain?
So, for example:
wrapTo2pi[9Pi/4]=Pi/4
I know such function ...
2
votes
0answers
42 views
Pattern matching and NonCommutativeMultiply
I am trying to define some functions using NonCommutativeMultiply and I am experiencing some strange behavior.
Consider the following expression
...
0
votes
0answers
69 views
2
votes
0answers
77 views
Error Message for GrammarRules and GrammarApply
I have been struggling with the following issue regarding an irregularity when deploying and applying GrammarRules. Specifically, it often takes several failed attempts before the execution is ...
3
votes
1answer
110 views
How to get the bit size (bit length) of an integer? [closed]
Suppose I have the integer 255, so 11111111 is its base 2 (bit) representation and the bit size of 255 is 8.
How can I calculate the bit size of a (big) integer in Mathematica?
Is there a built in ...
6
votes
2answers
129 views
Operators without built-in meaning are incompatible with parallel evaluation
Mathematica has a useful set of Operators Without Built-In Meanings. For example: CenterDot, CircleDot, ...
