Questions tagged [language-design]
for questions about the design of the Mathematica language itself
147
questions
1
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0
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48
views
Why do rules not default to local scope? [closed]
Consider the following:
80 //. a_?EvenQ -> a/2
a = 3
80 //. a_?EvenQ -> a/2
which outputs:
5
3
3/2
I think I understand ...
- 121
1
vote
0
answers
100
views
Why is the dot operator not just matrix multiplication?
It seems to me Mathematica does not have an inbuilt matrix multiplication operator. The dot operator fails as such, as is even noted under "Possible Issues" in its documentation it ...
- 111
4
votes
0
answers
73
views
Why does `MakeBoxes` have the HoldAllComplete attribute and ignore it rather than HoldAll?
MakeBoxes has the attribute HoldAllComplete. For a normal function, it would imply that Upvalues should not be taken into account when the expression is evaluated:
<...
7
votes
2
answers
373
views
Why do some functions require its arguments to be in a list while others accept these as a sequence? [closed]
With Midpoint[{{4, -2}, {2, 5}}], the vectors must be in a list.
But with EuclideanDistance[{-2, 2}, {3, -6}], they don't.
These ...
- 599
6
votes
1
answer
180
views
What is the difference between OperatorApplied and CurryApplied?
Reading both OperatorApplied & CurryApplied function documentations seems to indicate that they are essentially the same ...
- 253
2
votes
1
answer
196
views
Separating the Numerator & Denominator
It's been years since I last programmed in Wolfram & for the first few days, I felt like I've been feeling around the dark; now that I've mostly forgotten how to code it.
Again, I could be ...
- 181
4
votes
2
answers
208
views
What should mapping over a number or symbol produce?
I expected it to be an error (i.e., produce an error message), but Map[f,num] is num. Why is this the correct behavior? If it is ...
- 13.5k
1
vote
2
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99
views
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 ...
- 99
4
votes
1
answer
192
views
Differences between minimization functions?
There's more than 20 functions having to do with minimization
...
- 3,797
2
votes
0
answers
90
views
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:
...
- 121
9
votes
0
answers
65
views
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 ...
- 6,954
49
votes
6
answers
4k
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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 ...
- 968
2
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0
answers
114
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Why is ComplexQ not available? [closed]
For names = Names["System`*"]; executing the following returns 200 hits.
...
- 37.6k
-1
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1
answer
441
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 ...
- 37.6k
2
votes
1
answer
164
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 ...
- 245
19
votes
1
answer
425
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 (...
- 459
9
votes
1
answer
352
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 ...
- 860
1
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0
answers
55
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 ...
- 8,930
1
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0
answers
118
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 ...
- 812
0
votes
1
answer
132
views
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 ...
- 1,116
22
votes
1
answer
494
views
What's the difference between these 2 associations?
I have 2 associations similar to these simplified ones:
...
- 19.8k
0
votes
0
answers
43
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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 ...
- 2,315
3
votes
2
answers
429
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 ...
- 65
6
votes
1
answer
137
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 ...
- 1,597
26
votes
6
answers
791
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 ...
- 860
3
votes
0
answers
66
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 )
2
votes
0
answers
64
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 ...
- 6,046
19
votes
1
answer
237
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 ...
- 2,079
22
votes
1
answer
566
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 ...
- 988
5
votes
1
answer
77
views
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 ...
- 1,760
4
votes
0
answers
99
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) ...
- 61.3k
3
votes
1
answer
83
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 ...
- 1,419
1
vote
1
answer
91
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:
...
6
votes
3
answers
516
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
...
- 243
22
votes
1
answer
796
views
What are the benefits of Entity Classes for Databases?
To me, using the older database functionality is much simpler:
...
- 31k
6
votes
2
answers
250
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 ...
- 61
3
votes
3
answers
154
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:
...
- 2,030
1
vote
0
answers
85
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 ...
- 2,399
6
votes
1
answer
170
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 ...
- 46.6k
8
votes
0
answers
105
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
...
- 2,079
2
votes
1
answer
237
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
...
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 ...
- 8,973
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 ...
- 9,523
6
votes
1
answer
115
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 ...
- 33.3k
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 ...
- 1,049
2
votes
0
answers
123
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 (...
- 1,567
7
votes
1
answer
175
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 ...
- 61.3k
7
votes
1
answer
102
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 ...
- 61.3k
9
votes
0
answers
126
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:
<...
- 33.3k
4
votes
0
answers
96
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 ...
- 1,054