Questions tagged [language-design]

for questions about the design of the Mathematica language itself

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Please I need help to define a function of two variables (t,x)!

Let's define the following function: f[t_, x_] = t^2 + t*x*(1 - x) such that $x \in (0,1)$ and `$t \in (0,0.02)$ The problem is when I want to define the following ...
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3 votes
1 answer
103 views

Differences between minimization functions?

There's more than 20 functions having to do with minimization ...
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1 vote
0 answers
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Why does Plot function have HoldAll attribute?

I had an odd issue where my plot wasn't drawn correctly when I called it via Plot[Join[fs,gs], (*..*)]. However, these two versions worked: ...
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0 answers
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Get depth of vertices in TreeGraph

I want to get the depth of each vertex in a TreeGraph, g. I might convert g into an ...
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8 votes
0 answers
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Does ArgumentsOptions do anything we couldn't do without it?

ArgumentsOptions was new in version 12.2. I looked at the application on that page, and it makes code very difficult to understand. What if anything does ArgumentsOptions do for us that we couldn't do ...
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46 votes
6 answers
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How could Wolfram Research increase Wolfram Language adoption?

Introduction Hello, this is a more general question than is typically asked here. However, I chose to post it here because this seems to be the most active community for Wolfram Language / Mathematica ...
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1 vote
0 answers
98 views

Why is ComplexQ not available? [closed]

For names = Names["System`*"]; executing the following returns 200 hits. ...
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-1 votes
1 answer
293 views

Keywords for the Wolfram Language [closed]

For a programming language, certain keywords are reserved; i.e., these tokens can't be used in any other context while programming in that particular language. Here is a list of C language keywords ...
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2 votes
1 answer
157 views

How to think about the answer to Rationalize[-11.5, 1]

In the open source Mathematica implementation called Mathics, an issue was raised where Mathics computes Rationalize[-11.5, 1] as -12 rather than Mathematica which ...
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15 votes
1 answer
300 views

Programming language prototyping in Mathematica

Are you aware of any projects using the Wolfram language resp. Mathematica as an environment to explore the design of programming languages - in particular languages with a focus on mathematics (...
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8 votes
1 answer
241 views

How to write a simple interpreter / DSL with Wolfram Language?

I am specifically trying to write an interpreter for Mathematica predicates to MongoDB aggregation stages, but I wanted to phrase the question a bit more generically because I can see many times one ...
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  • 710
1 vote
0 answers
50 views

"Compile-time" patterns

If I define a function like f[x : {_, _Integer}] := (* function body *) then, as I understand it, every time f[expr] is ...
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1 vote
0 answers
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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 ...
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1 answer
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Is this a bug in Total?

The output from the last of these lines doesn't make sense to me Total[{}, {1}] Total[{}, {1, 2}] Total[{{1}, {1, 1}}, {2}] Total[{}, {2}] 0 0 {1, 2} 0 The 3 ...
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21 votes
1 answer
437 views

What's the difference between these 2 associations?

I have 2 associations similar to these simplified ones: ...
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0 votes
0 answers
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 ...
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2 votes
2 answers
349 views

Why are Quantity and Units inconsistent with regular Mathematica behavior?

When I enter this in Wolfram Mathematica V12: 0 Dogs + 5 Cats Mathematica sensibly returns this: 5 Cats BUT, if I using the ...
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3 votes
0 answers
95 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 ...
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24 votes
5 answers
539 views

Is mathematica adequately improving?

A bit of a loaded question, but in your opinion is Wolfram's team making good progress on improving their software? I've used Mathematica for almost 10 years now, and honestly I'm personally ...
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3 votes
0 answers
57 views

what are the principles of good design with Wolfram Language a la Zen of Python? [closed]

The Zen of Python — is a list of 19 general truths for Python design principles. ( https://medium.com/@Pythonidaer/a-brief-analysis-of-the-zen-of-python-2bfd3b76edbf )
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1 vote
0 answers
62 views

Should SubsetMap be called CombineAt?

I'm a big fan of the functionality introduced by SubsetMap but am puzzled as to why it was not called "CombineAt". There are ...
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19 votes
1 answer
214 views

Why does OperatorApplied by default reverse the arguments?

Perhaps this is just one of those Mathematica curiosities, but I'd like to know why by default OperatorApplied[f][x][y] === f[y,x] versus the more usual way one ...
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22 votes
1 answer
468 views

Series vs Asymptotic in 12.1

The functionality of Series and Asymptotic (new in V12.1) is very similar. In fact, they are both listed in the Asymptotics ...
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5 votes
1 answer
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Missing["reason"]—can any reason be used?

Can any string be used as a "reason"? Or is there a specific list of acceptable reasons? For instance, Missing["refuse"] works as a missing? Is there any ...
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4 votes
0 answers
93 views

Obtain complete list of built-in graphical objects, and split them into groups?

I would like to obtain the complete listing of built-in graphical objects (which can be used in Graphics or Graphics3D) ...
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3 votes
1 answer
80 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 ...
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  • 1,399
1 vote
1 answer
85 views

Variable substitution like usual maths

So... I'm trying to get some simplifications on equations using own defined variables, but the tries I gave didn't result on what I wanted. The problem: I have 2 variables defined as: ...
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6 votes
3 answers
503 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 ...
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  • 243
20 votes
1 answer
703 views

What are the benefits of Entity Classes for Databases?

To me, using the older database functionality is much simpler: ...
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6 votes
2 answers
189 views

Separation of statements vs "space mul", formal definition of Mathematica syntax?

In Mathematica, space can often be used to indicate multiply. For example "a b" = "a * b". On the other hand, in a *.m file, we also have multiple statements separated by newlines. How does the ...
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3 votes
3 answers
143 views

Why Graph does not recognize chains of vertexes like NetGraph

Cross posted on Wolfram Community. Perfect logic: NetGraph[{1, 1, 1}, {1 -> 2 -> 3}] But this does not make sense: ...
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1 vote
0 answers
83 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 ...
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6 votes
1 answer
143 views

Making an Association-like interface for HashTable

System`Utilities`HashTable is conceptually a lot like an Association but it has the pretty phenomenal (for Mathematica) property ...
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8 votes
0 answers
104 views

What is the philosophy behind \[Rule] (a.k.a. `->`) for assigning options?

Today I was banging my head against my desk when I realized that the problem I was experiencing was due to having typed ImageSize[Large] instead of ...
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2 votes
1 answer
187 views

DeleteCases not working as expected

I am trying to reproduce the example of Data Cleaning from here. I had to make a slight change in input 13 to ...
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44 votes
1 answer
2k views

What's the deal with next generation Wolfram compiler?

Sources: Old Compiler (Rob Knapp Nov2011) Computer Science in Mathematica (Abdul Dakkak Dec2014) Compilation Technology (Tom Wickham-Jones, Abdul Dakkak & Steve Wilson Dec2015) The Wolfram ...
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18 votes
2 answers
1k views

Why it seems that there is no counterpart function as to multiplication, to `Total` as to addition?

Times and Plus have the same grammar, and so do Product and ...
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6 votes
1 answer
106 views

Counterintuitive DownValue precedence

Consider the following definitions for two symbols: foo[a] /; True := b foo[a] := a foo[a] (* a *) foo2[a_] /; True := b foo2[a_] := a foo2[a] (* b *) (The ...
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21 votes
4 answers
1k views

Is expression in Mathematica well defined?

According to Mathematica, everything is an expression. So an atom is also an expression. But in other parts of documentation, they say that an expression is of form ...
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2 votes
0 answers
106 views

Areasinus hyperbolicus [closed]

Why is there a function ArcSinh[]? Shouldn't this be called ArSinh, since it is connected with an area and not with the length (...
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  • 1,547
7 votes
1 answer
162 views

What is the logiс behind handling alpha-channel by various image-processing functions?

(Cross-posted on Wolfram Community.) When working on the answer to this question I discovered that starting from Mathematica 10.0 the behavior of such functions as ...
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7 votes
1 answer
101 views

A bug and inconsistency in current image arithmetic operations?

Let us start from a single-pixel RGBA image: i = Image[{{{0., .4, .7, .8}}}, Real, ColorSpace -> "RGB"]; Multiplying by .5 ...
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9 votes
0 answers
112 views

List assigment ({...}={...}) and UpValues

Let's say I want to track any assignment attempt for a variable a: a /: Set[a, x_] := Print@{a, x} This works as intended: <...
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4 votes
0 answers
85 views

Why is SparseArray atomic?

This answer tells us that functions like ReplaceAll do not straightforwardly work for the entries of sparse arrays because a ...
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  • 1,032
4 votes
2 answers
719 views

Module inside Module. Conflict of names in arguments

I have a module which calls number of other smaller helper modules. But those other helper modules are not used by another module, so there is no needed to have them in global context. So I wanted to ...
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  • 108k
1 vote
2 answers
134 views

Why can we assign a value to a function that has not been defined yet?

Consider the following snippet, fib[1] = fib[2] = 1; fib[n_Integer] := fib[n - 1] + fib[n - 2] As a newbie, it seems for me, the first line assigns 1 to ...
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6 votes
2 answers
252 views

WL terminology: evaluate, call, invoke, use, etc

A WL (Mma) program is a sequence of expressions to be evaluated, which generally involves applying commands and functions to actual arguments. What is the accepted terminology for what I think of as ...
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  • 12.3k
3 votes
1 answer
171 views

Single argument operator form?

I've heard the explanation that functions like StringDrop[] are varargs and so that is why they do not have an operator form. But when you are only using the ...
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  • 3,720
5 votes
0 answers
63 views

Why ReadList ignores NullRecords for Number?

When thinking on this recent question the immediately obvious solution which came to my mind was to use ReadList with options ...
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3 votes
1 answer
152 views

Span starting from the end

I could not find something similar. Given, e.g. lst = Range[10] (* {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} *) the following gives the reverse of ...
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  • 4,714