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Questions tagged [core-language]

Questions on the basic structure of the Mathematica language (Wolfram language) including atomic data types, syntax etc

2
votes
1answer
50 views

Inspecting Mathematica object

I'm using ProofObject for my question, but it applies to other objects too. FindEquationalProof returns ...
1
vote
0answers
62 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
286 views
5
votes
1answer
54 views

unexpected result from augmented assignment to association

Is the last of these results expected? If so, how? ...
1
vote
0answers
33 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. ...
2
votes
1answer
40 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
423 views

Can we make a faster Boole implementation?

I just learned about Mr. Wizard's very efficient code here. ...
1
vote
3answers
74 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
49 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 ...
3
votes
1answer
45 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
251 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
197 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
98 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. ...
4
votes
1answer
55 views

How can I evaluate only the (bound) variables in an expression?

Given an arbitrary expression, how can I have Mathematica only evaluate the (bound) symbols, i.e. replace them by their respective values, but not do any further simplification/evaluation of the ...
0
votes
1answer
34 views

FunctionExpand vs FullSimplify

The documentation (v.11.3) says: "FunctionExpand is automatically called by FullSimplify." Why then does ...
1
vote
1answer
41 views

undesirable/buggy change in behavior of Limit in Mma 11.2?

The behavior of Limit changed in Mma 11.2, and I think it is in some ways undesirable or possibly buggy. Consider ...
1
vote
1answer
78 views

What resources can I use to become familiar with high level syntax?

I was reading a question about dropping higher order terms and realized that I have a serous gap in knowledge when it comes to the finer points of mathematica computational programming. Are there any ...
1
vote
0answers
45 views

What use is empty binding list in `Block[{},…]`? [duplicate]

Spelunking the Export function, I stumbled upon the following definition: ...
11
votes
1answer
113 views

stable sort for association?

Should I be able to use the "list of functions" approach to getting a stable sort of an association? In 11.1 I see, ...
7
votes
1answer
98 views

advantages of ApplySides?

Version 11.3 introduces ApplySides for situations where I usually use Map. What is an example where ...
3
votes
0answers
125 views

How to achieve with Mathematica the effect a closure has in other languages?

Motivation I want to write an auxiliary function (brief auxf) for testing the output of another function that evaluates its body repeatedly using ...
6
votes
1answer
119 views

Is (x|y|…)∈set the same as x∈set&&y∈set&&…?

I've sometimes seen that this operator is used to specify that each of given variables is in some set, e.g. Reals. Like ...
11
votes
2answers
108 views

Can a Symbol have more than one OwnValue?

The DownValues, UpValues, and OwnValues functions are all plural. In general, a Symbol may ...
4
votes
1answer
69 views

SetDelayed not working as expected

According to the manual, "A variable defined with SetDelayed is evaluated every time it is used". The code below suggests otherwise. ...
12
votes
1answer
144 views

Check if symbol is in core language

How can I check if a symbol is pre-defined by Mathematica, in a way that's backwards compatible with old versions? i.e. I would like some CoreLanguageQ[x_Symbol] ...
1
vote
0answers
35 views

Convenient value assignments in OOP

It is possible to implement OOP in Mathematica using something like obj=c[<|a->1,b->2|>] and it's convenient to extract value from the object by ...
0
votes
0answers
33 views

How can I extract the numerical value from the result of FindRoot [duplicate]

I've to use previous values of FindRoot to implement my program (recursively), but the type of the output from FindRoot is not a number. How can I extract the ...
4
votes
3answers
173 views

Keep only rules that replace integers with other integers

Let's say I have a list of replacement rules: List1 = {2 -> 3, b -> 5.5, 6.57 -> 2, 3 -> 4.5, 1 -> -1, 0.03 -> 0.5, 9 -> a} The desired ...
0
votes
2answers
49 views

Numerical integration with a fixed sampling size, skipping points [closed]

I have a large number of data points to integrate over numerically. I would like to sample only some of the points and use a rather large step size just to reduce computation time. Say the data ...
0
votes
2answers
43 views

NIntegrating in $n$ dimensions?

I need to make a function that takes a function $f$ and a natural number $n$ and returns the integration from -inf to inf in all the $n$ dimensions of $f(x_1,\cdots,x_n)$. With Integrate I would do ...
1
vote
1answer
47 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
1answer
86 views

how can i convert my matlab conde into mathematica or atleast convert the bisection program? [duplicate]

(Convert matlab code into mathematica code) (I'm fairly new to mathematica) (bisect function matlab code:) ...
0
votes
1answer
62 views

SplitBy and mod 2 [closed]

I wish to group semiprimes into groups with same parity. Mathematica does this well with SplitBy[ Select[ Range@ 100, PrimeOmega@# == 2 &], Mod[#, 2] &] ...
0
votes
1answer
100 views

Why 1 is not recognized as real? [closed]

I'm not understanding smth simple. Why is 1 not recognized as a real number in the second line?
3
votes
2answers
191 views

Writing a bisection root finder

I'm trying to make a simple function that will calculate roots of equations by using bisection method. My code isn't working right. Can anyone take a look and help me? Here is the code: ...
10
votes
1answer
333 views

What does the ToList function do, and where did it go?

I am trying to revive some code from 2015 (version 10?) which uses the function ToList. I can not find it defined in any notebook on my system (in fact, it only ...
-3
votes
3answers
189 views
11
votes
2answers
1k views

Can't understand one paragraph in Power Programming with Mathematica

In the chapter 7 of the Power Programming with Mathematica, there is a paragraph discussing the behavior of Set- functions: (page 205. (pdf version p. 224)) ...
1
vote
0answers
35 views

Is Construct introduced to replace Function application? Should it be treated as such an alternative?

I noticed that v.11.3 got released the other day; it was exciting so I went through the Summary of New Features in 11.3 to catch a glimpse of what's new and see if there is something I should keep in ...
0
votes
1answer
127 views

Why is Null printing?

I am making a function that will evaluate several other functions, using the same inputs, in my program and give me the results. I am using Print to do this (see ...
2
votes
1answer
94 views

Can the pattern “_.” be used in head?

The standard usage of the pattern _. seems usually used in the parameter, for example, f_[a_,n_.]. I wonder if such pattern can ...
0
votes
0answers
33 views

Conditional access to entities in Wolfram knowledge base

I am trying to get the name of stars that are in a range of distances from the Sun. The Input I have tried is: ...
1
vote
2answers
38 views

How can I get a variable to be recognized as an array when computing expectation for multivariate distributions

The following expression works correctly: Expectation[ x^4, {x, y, z} \[Distributed] MultinormalDistribution[{0, 0, 0}, IdentityMatrix[3]]] But when I ...
7
votes
1answer
54 views

Abort but keep what was already calculated

This is a very general question I have about aborting a running computation but keeping what was already generated. Let's say that I perform a numerical optimization over a list of parameters. ...
1
vote
0answers
48 views

Is there a MaxPosition function? [duplicate]

The Max and Min functions return values, but I would like to have the position(s). Is there a standard function that does this? ...
1
vote
0answers
45 views

Why is Part designed to sometimes wrap the original head around the parts it extracts? [duplicate]

For me, the natural meaning of the function Part is "get the sub-expression at appointing position." It is quite unlike Take, <...
7
votes
3answers
282 views

Testing equality of graphics

Is there a way to reliably test the equality of two plots? Consider this: plot1 = Plot[Sin[x], {x, 0, 2Pi}]; plot2 = Plot[Sin[x], {x, 0, 2Pi}]; You'd think ...
3
votes
3answers
126 views

aggregate records across dates

Each record in a dataset includes a country name, a year, and observations (e.g., GDP) for that country in that year. I would like to generate a new dataset with one record per country (so I would ...
10
votes
1answer
267 views

Why use pure functions?

I've now read the official documentation of wolfram on (anonymous) pure functions, and the part about (anonymous) pure functions in the book "mathematica programming intro". I believe I understand ...
3
votes
2answers
93 views

What exactly do single brackets represent syntactically?

I'm trying to deepen my understanding of the mathematica language after having messed around with it for a long time. I'm reading the book "mathematica programming Intro". Unfortunately, I don't ...