Questions tagged [core-language]
Questions on the basic structure of the Mathematica language (Wolfram language) including atomic data types, syntax etc
447
questions
5
votes
3answers
440 views
Is $2x$ documented?
According to the official documentation of Times[], multiplication of $x$ and $y$ is represented as one of
x*y
x×y
...
2
votes
1answer
71 views
Question about iteration [closed]
I have the following expression:
sol1 =
(11 + 3*δ - 11*θ + 4*m*θ - 3*δ*θ - 8*Sqrt[(-(2 + δ))*(-1 + θ)*(1 - θ + m*θ)])/(4 + 4*δ)
I want to plug numbers into $ \...
13
votes
1answer
189 views
Memory leak in the system function: how to free memory without restarting the kernel?
$HistoryLength = 0;
Warming up:
TextSentences[StringJoin@RandomChoice[Join[Alphabet["Russian"], {" ", "."}], 100]];
No ...
0
votes
3answers
76 views
2
votes
2answers
121 views
Vectors and Matrices
Mathematica makes no distinction between columns and rows. Yet, that is a BIG deal in the classroom. Does anyone have a source that explains how Mathematica manages to make every vector a list and ...
5
votes
1answer
273 views
Operator currying: how to convert f[a,b][c,d] to {a+c,b+d}?
This question is related to this golfing question (but I'm not interested in golfing, only in functional operator composition):
How can we convert f[a,b][c,d] to <...
22
votes
1answer
216 views
Possible Memory Leak Issues in NestWhile
Consider the following code snippet:
NestWhile[{#[[1]]+1,Pause@.001;ConstantArray[0,{100, 100}]}&,
{1}, (#[[1]] <= 10000) &, 2]
In theory, when ...
2
votes
1answer
82 views
Basic question regarding returning values from user-defined functions [closed]
I'm new to Mathematica today. I would like to write a function that will implement the following pseudocode:
f[x_]:=
Do something
return y
I have searched ...
6
votes
1answer
67 views
Can I stop a running NDSolve calculation without losing the data it obtained so far?
I would like to solve a system of ODEs numerically using NDSolve on an interval {t,t0,tf}.
For the systems I currently solve, ...
1
vote
0answers
45 views
Can I store output data in the Notebook file? Specifically output from NDSolve[ ]
I am having some outputs from NDSolve of the form
{{x→InterpolatingFunction[…], y→InterpolatingFunction, … }}
and the ...
7
votes
1answer
505 views
The Wolfram Kernel must be activated for WolframScript to use it
I'm using the free Wolfram Engine for developers, but somehow I cannot activate it.
...
3
votes
2answers
132 views
Print characters from list with a For-loop
Suppose I have the list
primary = {"b","a","e"}
I want to get the following output with a For-loop (or While-loop)
"b"
"a"
"e"
My code is:
...
10
votes
1answer
556 views
Row vectors and column vectors (Mathematica vs Matlab)
As far as I know, Mathematica does not distinguish between row vectors and column vectors: all vectors are seen as lists. I know ways to bypass this as suggested here Product between a column vector ...
1
vote
1answer
135 views
Error plots in MMA 12.0
Suppose I have the following data and associated quartiles:
data = RandomReal[{0, 1}, {40, 10}];
qs = Quartiles[data]
I want to make an ErrorListPlot from the ...
11
votes
2answers
218 views
Selecting elements from a list where the order is set by another list
I have two lists, list A and list B. All of the elements of A are members of ...
8
votes
2answers
220 views
Surprising behavior of Part[ ]
Look at this list
list={1,2,3,4}
Obiously
list[[1, 2]]
throws the error:
During evaluation of Part::partd: Part ...
2
votes
0answers
29 views
one Dataset from multiple csv files
In one folder I have many csv files, all sharing an identical header. I can use SemanticImport to produce a Dataset from each ...
0
votes
1answer
127 views
How can I translate some JavaScript code into Mathematica code? [closed]
I am a programmer and would like to understand another field outside of the procedural thinking of if-else and for.
I would ...
16
votes
2answers
322 views
Around usage results
Why is
Around[10, 1]^2
+- 20
and
Around[10, 1] Around[10, 1]
giving 100 +- 14 ?
Just curious I would suspect them to ...
0
votes
1answer
55 views
Deriving a list of time differences from a column in a dataset and appending the list as a new column
I know it's a beginner question, but I've struggled with it for some time now and can't find a solution.
I have a dataset consisting of timestamps, where I've managed to compute the time differences ...
10
votes
4answers
539 views
What is the accessibility of a package's `Private` context variables?
I've been reading up on how Mathematica handles contexts, $Context, $ContextPath, and a few of the tutorials they have on ...
3
votes
1answer
73 views
How to trace value assigned to local variable(variables in Module)?
Bug introduced in v10.1 or earlier and persists through v11.3
CASE:4240757
Here is my code:
...
1
vote
0answers
90 views
Design completion idea for Position [closed]
This is not exactly a question but rather a suggestion for a design which I think would greatly improve Mathematica. Before I put this to Wolfram Research I would like to see what other people think ...
1
vote
2answers
105 views
Computation with arrays of numbers
My code is
m = RandomVariate[NormalDistribution[], 100];
c = 0.1;
f1 = RandomVariate[NormalDistribution[], 100];
F = Sqrt[c]*m + Sqrt[1 - c]*f1;
I would like to ...
0
votes
2answers
33 views
My function for computing a partial derivative generates an error message [closed]
Apologies, I'm still new at Mathematica. I have defined the function
...
1
vote
2answers
60 views
Using a Do-loop to find divisors mod 13 [closed]
I want to check sum of divisors of i mod 13 fori = 1 to i = 20. I tried writing a Do-Print ...
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 ...
5
votes
2answers
95 views
Converting prefix to infix
Is there a way in Mathematica to convert prefix to infix notation (where precedence order is preserved)?
For example, how would I convert S[a, S[b, c]] to ...
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 ...
1
vote
2answers
88 views
Change the output for `Times`function
When I have an input like:
1/2*k
The output is:
How to change the output of Timesfunction to see this result:
Another ...
1
vote
1answer
67 views
Defining iterative algorithms [closed]
Assume the iterative algorithm of interest to be as follows:
...
3
votes
2answers
71 views
Iconize behaves in a confusing manner
When I evaluate Iconize[Range[10], "range10"], it returns an icon labled "range10", which if evaluated returns ...
12
votes
2answers
121 views
Bad Float Counts? (Length[xs] != Total@Counts[xs])
In Mma 11.3, tallying floats with Counts seems to fail. (Tally works fine, and rounding fixes the problem.) Is this behavior ...
1
vote
1answer
37 views
using strings from a header row as “pointers”
Suppose I have a list like:
data={{"product","amount","price"},{"A",1,100},{"A",3,100},{"B",5,200}}
I could use a Map to calculate over each row the "amount" * "...
0
votes
0answers
60 views
Implementing a function that exhibits linearity
I am trying to define a function $\mathbb{E}_t$ such that $\mathbb{E}_{t}[f[x_{s}]] = f[x_{s}]$ if s<=t, and $\mathbb{E}_{t}[f[x_{s}]] = \mathbb{E}_{t}[f[x_{s}]]$ if s>t. $\mathbb{E}_{t}$ is ...
0
votes
0answers
88 views
Is there a direct way of adding two random step size lists
As shown in the figure, I have three lists a,b and c. I want to see whether a + b +C0= c(here C0 is a constant).
Since list a and b have varing step size (...
6
votes
2answers
156 views
Flat attribute : example I don't understand
I am just beginning to learn about attributes of function in mathematica.
I saw the example "Flat". But there is something I don't get :
...
2
votes
1answer
67 views
Inspecting Mathematica object
I'm using ProofObject for my question, but it applies to other objects too.
FindEquationalProof returns ...
1
vote
0answers
64 views
Is there packages can help read, analyze or understand MMA codes? [closed]
Sometimes, I think that it's difficult to learn high level codes, or even when looking back on some long lines of codes I myself had written, espectially when lots of pure-functions was used, so I'm ...
5
votes
3answers
343 views
6
votes
1answer
64 views
unexpected result from augmented assignment to association
Is the last of these results expected? If so, how?
...
1
vote
0answers
43 views
raise error on type mismatch
Is there a best practice for raising an error on a type mismatch? For compiled functions I'm guessing the answer is the use of GeneralUtilities`WithMessageHandler. ...
3
votes
1answer
60 views
Module - Symbols out of scope of lexical scoping
The Problem
Consider the following code (1):
In[1]:= x = 2;
Module[{x, y},
y[x_] = x;
y[1]
]
Out[2]= 2
I expected the answer ...
7
votes
2answers
439 views
Can we make a faster Boole implementation?
I just learned about Mr. Wizard's very efficient code here.
...
1
vote
3answers
112 views
Unable to implement bisection method using recursion [duplicate]
I have tried to implement a bisection method for finding roots using SetAttributes[BisectionItt, HoldAll] and then ...
0
votes
0answers
56 views
How can I better formulate a conditional statement?
To solve optimization problems I have seen this:
Is there a more elegant way to do this with alternative conditional expressions? Is there something equivelant to ...
4
votes
1answer
50 views
Is it possible to write an expression A such that Evaluate[Evaluate[A]] is different from Evaluate[A]?
Mathematica is cool for all sorts of "magic tricks", but I'm trying to get an idea on how the core term-rewriting system works. Is it possible to make a term such that the output of its evaluation can ...
17
votes
1answer
320 views
Distinguishing Wolfram Language and Mathematica, the software
Which features are part of Mathematica, the software, and which features are Wolfram Language?
I would say there has to be a line discriminating the two somewhere. One could say that Mathematica, in ...
14
votes
3answers
208 views
What is the difference between Set and SetDelayed when evaluating the RHS leaves it unchanged?
I thought there was no difference between f[a_] = 2 + a; and f[a_] := 2 + a; because the resulting ...
3
votes
1answer
118 views
Why did Set work instead of SetDelayed?
I started with the following expression
a[t_] := -Pi Sin(Pi/2*t)
where initial velocity is 2 Pi and initial distance is 1.
...
