Questions tagged [argument-patterns]
Questions concerning argument patterns used as formal arguments in function definitions (e.g., := expressions) to restrict the kinds of values that can be passed as actual arguments. Also questions about how such patterns can be used to achieve function overloading.
4
votes
1answer
96 views
A single argument pattern definition applies to multiple-argument patterns?
Consider defining a pattern rule, such as
myFun[x_]:=x
As far as I understand Mathematica syntax, this rule means
...
2
votes
1answer
35 views
Define different actions for the same operator depending on the nature of its arguments
I am working with terms of the form
A**B1**B2
where A, B1, and ...
5
votes
1answer
77 views
Why is { } interpreted as an option in my function? [closed]
I don't understand the output from:
...
1
vote
2answers
57 views
Defining a function that treats input as two unordered lists
I have a function f2 I'd like to code into Mathematica with the property that it takes in two lists, treats those lists as unordered, and maps to a symbolic value.
If I were instead using a function ...
6
votes
1answer
92 views
How to use VBA types with UNDERLINE in it's name in NETLink?
When coding with VBA functions in NETLink, I need the enum reference. It's ok to get the ...
3
votes
1answer
72 views
What does this syntax involving Entity mean?
I came across a different style of input while defining functions. Though I tried playing with this form, I have not understood how to interpret this input.
...
5
votes
5answers
322 views
Appending _?NumericQ automatically to every variable of a function in the definition [duplicate]
I have a list of expressions as follows:
as=Table[a[k],{k,1,500}]
I would like to append _?NumericQ to every element of this ...
0
votes
1answer
41 views
Relations between Function Variables in Computations
I have the relation λ=c/f, respectively f=c/λ and a simple function n[λ_]:=λ²+1. I'd like to differentiate the function with respect to f, then plot it as a function of λ again. For this, I can define ...
6
votes
2answers
418 views
What does _. mean in patterns? [closed]
Here is a quick one, hopefully. I searched through different tutorials and documentation articles but haven't been able to find anything yet.
What does _. mean? As ...
2
votes
1answer
44 views
Creating a function that differentiates rational functions
I want to create my own differentiation function Derivada. So, I already set some properties like:
...
9
votes
1answer
194 views
Optional pattern behaves differently in version 8, 9, and 10+
We recently ran into an issue when testing Rubi on older versions. It boils down to this simple example which I didn't dare to simplify further as I cannot test it in versions < 10
...
0
votes
0answers
45 views
Functions definitions with variable arguments
How do you define a variable amount of functions with a variable amount of arguments? I don't get the reference at all :
...
4
votes
2answers
409 views
why doesn't this work to screen for Boolean inputs?
I routinely sanitize the inputs to a function using this sort of technique:
funcI[x_Integer] := Print[x];
But it doesn't work with Booleans.
...
0
votes
0answers
27 views
Defining functions with pattern as argument
I want to define a function such that
f[18/17 h[y][z]] = 18/17 z
for any function h[y][z].
I first tried with ...
2
votes
1answer
108 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 ...
5
votes
2answers
1k views
How to restrict the domain of a function
I realize this question has been asked many times, but I am fairly new at Mathematica and the other answers are very complex, and certainly too complicated for this simple code I am trying to write.
...
1
vote
1answer
85 views
NIntegrate fails because of symbolic evaluation [closed]
The following function can be plotted without any issues, say with ContourPlot, but NIntegrate fails because it tries to ...
5
votes
0answers
157 views
About the OptionsPattern[] approach of inheriting Options
Szabolcs showed in this post, that there are possibly two approaches to inherit function options. He recommended the Join approach. At first, I agreed. But today I ...
2
votes
0answers
42 views
Apply same type checking to every argument [duplicate]
Consider the following function which takes 10 arguments.
f[Io_, {θ_, ϕ_}][{x0_, y0_, z0_}, d_][h_][L_][ω_]
I know that all of these are of same type. I would ...
1
vote
1answer
65 views
How to require that a function argument be a pure function or a function-style replacement rule?
I'm trying to write a function whose first argument must be another function, defined either as a pure function or a function-style replacement rule. I don't know how to specify a condition on the ...
0
votes
1answer
51 views
How to turn a ruled pattern into a multivariable function [duplicate]
Fix m=2. My code generates a pattern like this one (n=2):
...
2
votes
1answer
69 views
Testing if list elements are numerical
I want to define a function with an argument, which is a list:
m = 10;
a = Table[k,{k,1,m}];
TestFun[listArg_] := Sum[listArg[[k]],{k,1,m}]
Now if I run the ...
1
vote
1answer
55 views
3
votes
1answer
77 views
A pattern involving Times
If I define (this is 10.0.0.0)
w[x : Times[xs__]] := {x, xs}
w[x : h[xs__]] := {x, xs}
Definition[w] gives me
...
0
votes
1answer
85 views
Function with number of arguments as parameter
I would like to write a function that generates the expression
$\sum_{i_1,\ldots,i_L} f(i_1,\ldots,i_L) \left(s_{i_1}\ldots s_{i_L}\right)$
where $i_j\in \left\{0,1,2,3\right\}$ and $s_{i_j}$ are ...
4
votes
4answers
141 views
How to tell the dimension of an argument function
Let's say I'm trying to write my own gradient operator function.
If I know the function is going to be $\mathbb{R}^2\rightarrow\mathbb{R}$, I could write
...
1
vote
2answers
54 views
Definine a function which accepts either functions or constants as arguments
I wish to define a function, which accepts either functions or constants as arguments. I tried
g[t_, y_] := Module[{}, t[y]]
which simply evaluates some function ...
2
votes
1answer
144 views
Argument pattern behavior for built-in symbol
I'm having troubles with this:
test1[forAll[t,x_]]:=x
test2[ForAll[t,x_]]:=x
While syntactically exact, test1 works and ...
1
vote
0answers
73 views
Using Two Arguments on the Same Function
I'm having some trouble wrapping my head around how I would go about using two arguments in one function. In the first section of the code below, I have scraped some "tweets" on the Seeking Alpha ...
3
votes
1answer
71 views
Dynamic number and position of arguments in a function
I'm trying to write a function (A) which calls another function (B) (in my case KroneckerProduct) where the number and the position of the arguments of function (B) ...
8
votes
2answers
1k views
A hack for aggressive type-checking?
I tend to like programming in a style where I can be very explicit about the types of expressions. While Mathematica isn't and shouldn't be a strongly-typed language like Haskell, I think it would ...
3
votes
1answer
133 views
Replacement rules with Lists
first time user and not quite familiar with how to enter my code here properly, but this isn't lengthy..
I have a previously defined function that computes the total time it takes to ride a bike with ...
5
votes
2answers
117 views
How to hold evaluation of a value that is passed to a function
Say, I want to take the first part of an operation in a function:
In: func[operexpr_] := operexpr[[1]];
func[a < b]
Out: a
But every once in a while a ...
10
votes
2answers
391 views
Smart Pattern Test
I defined two functions f and g which accept some argument which must be of some type, so I defined befor ...
12
votes
4answers
595 views
Optional argument that can be completely omitted?
I am writing a simple function return similar words.
Clear[similarWords]
similarWords[string_]:=Nearest[WordList[],string]
I want to add another argument ...
14
votes
1answer
299 views
How to define homogeneous functions that respect Euler's theorem of homogeneous functions?
A homogeneous function of degree $k$ is defined as a function that observes the following specification rule:
$f(a x_1, a x_2, ..., a x_n) = a^k f(x_1, x_2, ..., x_n)$
(see Wikipedia entry, ...
2
votes
0answers
65 views
Automating generation of argument error messages
You can run into messages like
DistributionFitTest["kk", "TestConclusion"]
...
2
votes
1answer
58 views
Finding an Argument Pattern for Function Defintion
I'm defining what's called a fractional integral in Mathematica, which acts on a list of functions that depend on $x$:
...
3
votes
1answer
82 views
How to speed up accidental large output?
From time to time I accidentally let large expressions like RandomReal[1., {10^5, 10, 10}] reach the front end. The computation of the result is quite fast (...
9
votes
1answer
201 views
Why is this syntax for patterns with Optional values not supported?
I want to express Optional[PatternTest[Pattern[a,Blank[]],t],1] concisely.
a : _?t : 1 is not quite this but works: ...
4
votes
1answer
88 views
Possible bug with `KeyValuePattern` and `Optional`
Bug introduced in 10.4, resolved in 11.0.0
I expect to get 0 on every line of output of this:
...
4
votes
4answers
214 views
How to scope `Pattern` labels in rules/set?
Module[{x},
f@x_ = x;
p@x_ := x;
{x, x_, x_ -> x, x_ :> x}
]
?f
?p
gives
...
1
vote
1answer
72 views
Part function: can we use pattern for part functions? [duplicate]
Can we use some patterns for the arguments of Part functions?
...
5
votes
2answers
156 views
How do I construct a Pattern with Alternatives and PatternSequence without getting Pattern::patvar messages?
Bug introduced 8.0 or earlier and persisting through 11.0 [CASE:3631078]
In Mathematica 8 and 9, defining this rule:
...
12
votes
3answers
613 views
How to check the validity of an option value
I have a user-defined function, func, which takes the following form:
func[arg1, arg2, options]
Here is the actual code
...
1
vote
0answers
52 views
Is there any point to using a variable as a function parameter?
Normally one only sees patterns as function parameters:
fun1[x_]:=x^2
Is there any point to using a variable in a function definition:
...
1
vote
1answer
87 views
User-defined density plotting function with a functional argument: extracting variables from the function and plotting in a circular region
I would like to customize the function DensityPlot and use it in a package as a function called MyDensityPlot:
The functions ...
5
votes
1answer
274 views
Multiple pattern test in the definition of a function
I have a very simple question, and I'm sure there is a way to do this but I cannot find it:
if I want to create a function that's defined only for matrices, I can do it like this:
...
0
votes
2answers
80 views
Function with translation property
I want to define a function Υ[b, x] of two arguments that has some special properties when there is a b in the second position:
...
4
votes
0answers
67 views
How to get f[x] to match with f[c_., x] when OneIdentity doesn't match
After setting:
SetAttributes[f, OneIdentity]
Default[f] = 1;
We have the following successful matches:
...
