Questions tagged [core-language]
Questions on the basic structure of the Mathematica language (Wolfram language) including atomic data types, syntax etc
502
questions
1
vote
0answers
34 views
Intervals v.s. Domains: when to use which and why?
or: How to use Interval correctly?
Mathematica provides these constructs for various symbolic deductions tasks. Among those constructs are symbolic number sets ...
0
votes
1answer
63 views
Strange little bug: Simple real number replaced by Times[0.805`, \.00] [closed]
I had a bug in my code which I tracked down to the simple number 0.805. So I looked at the FullForm of this number and I got
Times[0.805`, \.00]
It isn't a big ...
1
vote
0answers
81 views
Converting negative value to zero [closed]
I would like to convert the negative outcome of $r_2$ to zero. I have used the following code, but it still gives me a negative value. Is there any option to turn the negative outcome directly to ...
2
votes
0answers
60 views
Should I redefine 0^0 [duplicate]
I've found some times, while playing with combinatorics, that Mathematica can't calculate some functions because $0^0$ is not defined as $1$.
(I know that some people think that $0^0$ should be left ...
1
vote
2answers
94 views
'Do' loop acting on a global variable
I need a code that will allow me to alter a matrix (a global variable) iteratively using a function update (which depends on ...
0
votes
1answer
42 views
Expression unexpectedly not evaluating to a numerical value [closed]
When I calculate the below, I get an unexpected output, not giving me the density, but rather a value M * ..
...
3
votes
2answers
64 views
Basic replace with parameters questions
I have looked over MMA SE but seen nothing to help clarify this for me.
what I want to do is set some parameters for a curve, and then I want to automatically replace the x,y,z of, say, a vector field ...
16
votes
1answer
313 views
Broken ValueQ function in Mma12.2?
f[x] ^= 1;
ValueQ[g[x]]
returns True in Mathematica 12.2. Is it a bug?
1
vote
0answers
33 views
How to Inherit Arrowheds size?
I'm trying to write a Module that produces some arrows with custom Arrowhead shapes. However, I want the code external to the <...
0
votes
0answers
27 views
does Mma provide exact critical values of Mann Whitney U (small samples)
Does Mma provide exact critical values for the Mann Whitney U test, along the lines of haskell?
Or just as good, for given two small samples, can I easily ask ...
6
votes
0answers
179 views
InLine TeX input seems unstable
In the documentation of version 12.2 there is a new feature to input TeX as mentioned by Stephen Wolfram.
See: InlineTeXInput in the documentation.
After typing CTRL$ you can type in some TeX, and ...
0
votes
0answers
40 views
The command Total sums the entries of a list, is there a comparable command for the product of entries of a list? [duplicate]
I recently just found out about the command Total that gives the sum of a list. Was wondering whether there's an analogue that gives the product of the entries of a list? I see that there is the ...
1
vote
0answers
72 views
Can you create an indexed list of all Wolfram functions within a notebook? [closed]
Can you create a summary list of all Wolfram functions used within a whole notebook? Searched long and hard- no clear documentation found.
3
votes
0answers
81 views
How do I get built-in functions to use custom objects as if they were e.g. List?
(This is part 2 of my earlier question, Can I overload Part for specific heads (a la overloaded array subscripting)?, which was well-answered as asked.)
Overview:
My goal is to create a custom object -...
6
votes
1answer
99 views
Undefined Indexed Variable
I searched already a lot about indexed Variables, and it tends to be the most applicable way to use tensor notation. But I am having a hard time to solve for undefined indexed variables:
Here my ...
1
vote
1answer
84 views
Can I overload Part for specific heads (a la overloaded array subscripting)? [closed]
Mathematica/Wolfram Language newbie here.
The behavior I am after is to be able to "overload" the subscripting of me-defined objects/Heads and thereby use them as if they were ...
2
votes
0answers
24 views
Should `DiscreteLimit` work when the argument type is specified?
Is it expected that DiscreteLimit fails to evaluate whenever the argument type is specified? E.g.,
...
0
votes
1answer
67 views
Computmg the powers of a complex number? [closed]
this is the complex number im dealing with
zb=(1/7)* (Cos[Pi/3]+I Sin[Pi/3])
I need to represent for the first 10 powers in the plane. I also need to label the ...
0
votes
0answers
65 views
Why does Log[Abs[#]] return a complex number?
For a nonzero number $x$, $\log|x|$ should be a real number. Why does the following NestList contain non-real numbers when no numbers involved are close to zero? Is it a bug?
...
1
vote
0answers
40 views
How to eliminate a variable from coupled ODEs?
I found this question with an answer:
How to eliminate variables in ODE?
...
4
votes
3answers
260 views
How to programmatically modify a function definition
I would like to know an efficient method (without converting Mathematica Code to strings and string processing) of modifying a function definition programmatically. For example, I would like to tidy ...
2
votes
0answers
86 views
Why Does Subsets[…,{n}] not Output a Packed List, Even Though it Doesn't Unpack?
Assume list is packed.
I expect Subsets[] is a structural operation because it depends on the number of elements, not on what ...
0
votes
1answer
23 views
Speak misses words when executed first time in new cell
Version->12.1.1 for Microsoft Windows (64-bit) (June 19, 2020)
ReleaseID->12.1.1.0 (6959458, 2020061902)
PatchLevel->0
When I evaluate for the first time in a new input cell:
...
3
votes
0answers
112 views
Vector arrow notation in Mathematica
I want a fast way to type vectors in Text boxes like this: $\vec a$
I can do this manually with ctrl+7+"-> "
which creates this
...
0
votes
0answers
14 views
How do I combine evaluated expressions with unevaluated expressions
I want this function
PrintEvalExpr[Sin[Pi/2]]
Which outputs
Sin[Pi/2] == 1
I can either not evaluate, or evaluate but not at ...
11
votes
2answers
246 views
i_:0|1 varies in v12.1: incompatible change or bug?
Just check
i_: 0 | 1 // FullForm
In v12.0 or earlier the output is
Alternatives[Optional[Pattern[i, Blank[]], 0], 1]
But in ...
0
votes
0answers
41 views
Extention of Times operation causes bug in Expand?
I have the following code in Mathematica 11.01 :
...
2
votes
1answer
46 views
Splice matching function arguments
Mathematica 12.1 introduces Splice that replaces the old way of using Sequence@@ to "melt" a list of entries. However, the ...
1
vote
1answer
124 views
How do I evaluate my functions over a range of values? [closed]
I want to use the list of data which will come from MapData1 (in code); the first element is Īø and second is Action(I). I want to use this Action(I) and Angle(Īø) in ...
3
votes
1answer
45 views
Evaluate a Number head as a constant function
I wanted to use the parameters of a function in a distributive way, so for example
In[1]:= Through[(Cos+Sin)[x]]
Out[1]:= Cos[x]+Sin[x]
It works without problems ...
1
vote
1answer
34 views
Help with Evaluation controll/hold all attributes?
I'm making a sort of symbolic derivator, which needs to take its formulas in unevaluated form.
...
1
vote
0answers
41 views
If it possible to define a “function” such that the normal form will have the arguments in order? [closed]
I'm looking for something that acts like this.
How could ord be defined for 2 arguments? What about n?
Since Mathematica is a term-rewriting system it should be possible, but all my attempts were ...
5
votes
2answers
186 views
Is it possible to pipe(afterthought apply function) with options?
For example, I have the following
...
8
votes
2answers
380 views
How can I plot a parametric equation with ±?
I want to draw a parametric equation with Ā± like the figure below:
But I don't get the result I want when I run the following code. What can I do to get it?
...
asked Mar 27 '20 at 23:34
A little mouse on the pampas
5,0342 gold badges9 silver badges27 bronze badges
2
votes
1answer
63 views
odd output from DifferenceDelta
I would appreciate an explanation of why DifferenceDelta produces a complicated expression for a simple quadratic. I see that this is caused by the Real value <...
1
vote
1answer
45 views
Extracting argument of a specific functions in a large expression
I have a large expression, for example
Cos[x]Sin[y]Sqrt[1+z]/(1+x^2)-1/(1+y)
I wish to extract the argument inside Sqrt ...
13
votes
7answers
790 views
Getting the “root” Head
I have a dynamic list of function names, like {f1, f2, f3, ...}, and they will enter in computation in various forms ...
5
votes
1answer
124 views
How to label parameters in Manipulate
How do I label the "2" and "3" so they show "square" and "cubed" in Manipulate controls? The following is my code:
...
17
votes
6answers
1k views
A clean way to conceptually extract Parts from a circular list
I quite often run into a situation where I want to treat a list as a circular (repeating) list, and want to take a specific sublist of it, such as...
One past the end of the list:
...
7
votes
1answer
141 views
AtomQ[Counts[{a, c, d, b, a, c, b}]] gives True. Why?
I donāt understand this:
In[]: AtomQ[Counts[{a, c, d, b, a, c, b}]]
Out[]: True
It looks like an expression.
Does this have to do with the realization ...
1
vote
1answer
77 views
Implement a math command on a list of numbers [closed]
I have a set of numbers and would like to do the same math process on all of them.
Example:
data1={1,2,3,4,5,6}
Then have each number processed as Log(1), Log(2),.....
This seems like such a ...
6
votes
2answers
90 views
Assert no unevaluated function applications
Background
Suppose I have begun a fresh kernel session, and I have defined the following function alone:
F[x_, y_] := x + y;
One expected use of ...
5
votes
1answer
83 views
Plotting a NumericQ-protected function with the attribute HoldAll fails
Fixed in 12.1
This works:
ClearAll[f1];
f1[x_] /; NumericQ[x] := x;
Plot[f1[x]^2, {x, 0, 5}]
This does not:
...
6
votes
1answer
161 views
Are Hold attributes Mathematica's way to implement lazy pattern matching à la Haskell?
I'm reading this and I'm having a hard time understanding lazy patterns; in particular I'm baffled with the server-client toy problem and why there is a 'problem' of matching "...too early".
The ...
2
votes
1answer
75 views
Domain of `Sqrt[x]^2`
I'm just starting to work with Mathematica and this is simplified version of the problem I have: seems that Sqrt[x]^2 simplifies to just ...
1
vote
2answers
54 views
Assign numerical values to symbolic variables in a vector inside a do loop
I have vector k = {k1, k2, k3, k4, k5, k6}.
I would like to assign numerical values to the elements of k in each step of a <...
3
votes
0answers
117 views
Calling custom function from C++
I'm programming a project where I use multivariate symbolic polynomials. At some point I need to perform a PolynomialMod over a prime modulus, but the library GiNaC which I use works only over the ...
0
votes
1answer
39 views
is the behavior of WriteString surprising?
WriteString["temp.txt","this string"] returns Null but creates an open stream which is reused if you again ...
1
vote
1answer
82 views
How to clear all variables? [closed]
I have noticed that the old trick of using:
ClearAll["Global`*"]
does not appear to work anymore. It does not clear the values of any of my variables. I assume ...
3
votes
1answer
78 views
Understanding how List head works
I am trying to understand how Wolfram Language is actually meant to work and here is something that I fail to understand.
Apply[f, expr] replaces the head of expr by f.
So how come I get different ...
