Questions tagged [built-in-symbols]
Questions related to handling built-in symbols and functions, for example why they behave a certain (possibly unexpected) way.
153
questions
1
vote
1answer
68 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. ...
3
votes
2answers
101 views
What's the difference between 56 and Integer[56]?
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 ...
2
votes
1answer
93 views
Automated (lazy) method to make custom (key-input) shortcuts (not menu items) for letter-like symbols? [duplicate]
The Problem:
I don't know about you, but every time I am trying to do analytical work in Mma, it is rather difficult/cumbersome for me to type the following, here specifically for ...
0
votes
1answer
38 views
Symbolic Resultant Too Slow/Keeps Running
Evalutation of the following cell, which includes the symbolic resultant, of two univariate polynomials in $x$, with parameters $a,b,c$ for the first polynomial (of degree 4) and parameters $d,e,f,g$ ...
1
vote
1answer
47 views
JoinAcross with multiple associations
I would like to use JoinAcross to combine several lists of associations. Extending an example from the documentation, I'd like to do this:
...
0
votes
1answer
30 views
Apply Expand only to parts of expression
I have the following term:
term = (x AngleBracket[x (-x+Sum[v'[y[j]],j])])/AngleBracket[x^2]+Sum[v'[y[j]],j];
term //TeXForm
$\frac{x \left\langle x \left(\sum ...
4
votes
2answers
207 views
Underflow error General::munfl from E^x instead of Exp[x]
In contrast to earlier versions, Mathematica 11.3 and 12.0 generate lots of underflow errors from my code, e.g.
...
0
votes
0answers
23 views
Redefining the inbuilt function and its derivative [duplicate]
I want to redefine the DiracDelta functions and its derivatives. I am successful at redefining the DiracDelta function but not ...
2
votes
1answer
80 views
How I can get glyphs from a fraktur font and use them as identifiers?
I would like to use the fraktur-S ($\LaTeX$: \mathfrak{S} $\mathfrak{S}$; Unicode: "U+1D516" 𝔖) as a variable name in Mathematica, but pasting the Unicode ...
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 ...
5
votes
1answer
61 views
How to reset a built-in symbol to its default definition?
I'm trying to add functionality to some of Mathematica's built-in functions in a package I'm building. I'm not trying to overwrite any functionality—just add it where it isn't already defined.
I ...
4
votes
2answers
92 views
DisplayForm problem with $\pi$ in FractionBox
The following line produces an output with the text "Pi" displayed instead of the symbol (greek letter) $\pi$.
Code line:
FractionBox[π,2] // DisplayForm
...
10
votes
1answer
228 views
Who or what is named character Andy?
I suspect \[Andy] was meant to represent a staff member, or at least a person of importance.
I tried the F1-"Wolfram Search", Wolfram|Alpha and a simple ...
10
votes
1answer
137 views
Why does Success[…][key] work and Failure[…][key] doesn't work?
I'm trying to figure out what is a quick way to add error reporting to my user defined functions. I was experimenting with Success and ...
3
votes
2answers
245 views
How to find the list of all the elementary functions in mathematica?
Is there any command to give me the list of all the embedded elementary functions in Mathematica like Cos Sin Cosh Sinh Log and so on?
3
votes
1answer
52 views
Is using Length more efficient than using === as stopping criterion?
I am using
NestWhileList[
f[#, elems]&,
pairs,
Length[#1]<Length[#2]&,
2, Infinity, -1
]
to generate all suitable subsets from ...
0
votes
0answers
39 views
Create library of custom functions [duplicate]
I have been trying to create a library of custom functions that I could just call at the start of every notebook.
For instance, say I want the following functions to be part of the Library, or even ...
5
votes
0answers
99 views
Not comprehending PowerMod
Bug introduced in 10.3 or earlier and persisting through 11.3.0 or later
The bug is not present in 10.0.
By definition, PowerMod[a, 1/r, m] finds a modular rth root of a mod m.
Here's a pair of ...
1
vote
2answers
68 views
CountryData and RailwayGaugeLengths
Looking to see how to extract out just the length for this search:
...
1
vote
1answer
34 views
From algebraic symbols to symbolic functions
i have a code which gives an output of this kind:
rrr=2*f+1;
Now i define a simple function:
f[x_]:=3*x+2;
How should i do ...
0
votes
0answers
33 views
Mathematica does not recognize NestGraph
When I try to use the built-in command NestGraph, Mathematica doesn't recognize it. So it just outputs whatever I put in without doing anything. Do I need a special package for NestGraph?
0
votes
0answers
43 views
How can I simplify expressions correctly?
the final output of my code gives this expression which i call ttt:
...
1
vote
1answer
58 views
Substitution of expressions for the output
I have a code which gives this kind of output :
W = Sum[v[j]*b[j], {j, 1, 3}];
AA = (v[1]*b[1] + v[2]*b[2] + v[3]*b[3])*2 + 3 ;
I know that if i want to ...
3
votes
2answers
175 views
Transferring DownValues
I have a code in which I define something like this:
cc[1, 2] = 1;
cc[2, 6] = 12;
cc[3, 7] = 3;
After some manipulation I define a sort of temporary variable ...
1
vote
1answer
45 views
4
votes
2answers
693 views
Replacing dot by *?
I am unable to replace dot by *.
Replace[a.a, .-> *]
Is there any solution to get this done?
5
votes
3answers
165 views
Power Function and Non Commutative Multiply
I'm trying to figure out the best way to define a Power function for non commutative multiply that retains some of the regular features of the ordinary power function. As of now, what I've been ...
3
votes
1answer
91 views
What does the $ sign do? [duplicate]
I saw this uses $, but it was not clear what does it do there.
...
6
votes
5answers
253 views
First evaluate in place all subexpressions matching pattern before substituting result
ReplaceAll[expr, {patt1:>rhs1, patt2:>rhs2, …}] works by looking for and making all possible replacements of subexpressions in ...
7
votes
3answers
521 views
Is there a built-in function to get the centroid of a table?
Suppose I have a table with some data that are 'lumped' around some central location, such as the dummy example
...
6
votes
2answers
158 views
How to create non-rectangular array with Array?
From the answers to this question, I learned that the recommended way to construct a symbolic sum of terms in an expression is to use Array.
But I'm having a ...
1
vote
1answer
50 views
Low level built-in function to transpose expression (not array) [closed]
I have an expression like this
F[G[1, b], G[3, y], G[4, y], G[5, u]]
that I would like to Transpose to obtain
...
7
votes
2answers
156 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
...
7
votes
2answers
294 views
How to obtain list of Installed Packages loadable by Get (<<)
When Get["MyPackage`"] is executed, Mathematica looks for a package in $UserBaseDirectory/Applications, and it does, it will ...
0
votes
0answers
27 views
Built-in function to know if a list is inside another? [duplicate]
For example, if the function is f[a_List,b_List] then in f[{a,b,c},{a,b}] and ...
1
vote
2answers
116 views
Is there an error pertaining to HypergeometricU function on functions.wolfram.com?
If one clicks on the last of the nine formulas on the Wolfram Functions site, one obtains ...
1
vote
1answer
57 views
any possible meaning to a “terminal” slash (/)? [closed]
I've been directed to the web page
http://functions.wolfram.com/07.31.16.0001.01
The first statement in the formula is
...
4
votes
0answers
99 views
Crossing a symbol like p, similar to HBAR
Is it possible in Mathematica to cross a symbol like p, similar to h-bar, used to denote the Planck constant?
Picture in case of font problems:
In case of h, we have HBAR, inputted as ESC-hb-ESC ...
2
votes
1answer
39 views
Question related to IntegerPart
I am having trouble understanding the following result:
Through[{IntegerPart,FractionalPart}[{100 4.02}]]
{{401}, {1.}}
...
6
votes
2answers
646 views
How to take top 10 built-in function
WolframLanguageSymbol has a property named Frequencies, such as
...
4
votes
1answer
84 views
Is there a PartDelete like there is a TakeDrop
TakeDrop is nice because after taking a subarray, it also returns the remaining subarray. But it is limited in that the part specification can only be ranges, and ...
2
votes
1answer
63 views
Get polynomial terms
Is there a command equivalent to that of Coefficient to get the terms of a polynomial which are a power of the variables?
For example:
func[(x^3 + x)^2]
{x^2, ...
1
vote
1answer
78 views
Functions aren't executed
Can't figure out why Mathematica doesn't want to execute built-in functions? What can be wrong?
Input:
...
-1
votes
1answer
90 views
meaning of variable equal dot [closed]
I came across a program which I have written in a simplified form.
For[i=1,i<100, i=i+1;
func = a x^i;
func=.
];
What is purpose of "func=."?
4
votes
3answers
324 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
244 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
140 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
62 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
193 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
...
