For questions on writing functions (pure or using Set/SetDelayed) for any purpose, including the features that may be incorporated in those functions, such as options, patterns and conditions.

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10
votes
2answers
694 views

NestList on a function of several arguments

I'd like to know if it is possible to use NestList on a regular function of several arguments, such as: ...
4
votes
2answers
2k views

How to find (numerical) value of a derivative at point?

I have the following function: f[0, 0] = 0 f[x_, y_] := Exp[-(x^2 + y^2)^(-1)] How do I find its partial derivatives at any given point, including $(0,0)$? This ...
2
votes
2answers
147 views

Constraining a random function

This question is a follow-up from here. I have a function that generates a list of correlations between some random variables: ...
9
votes
1answer
650 views

Functional programming and Do loops

I'm writing a Monte Carlo simulation. I'm using a Do loop to create the different simulations, iterating over different ...
12
votes
1answer
245 views

Is it possible to Clear all variables (but not functions)?

I have written a Mathematica script in which I define functions and variables. Here is a vastly simplified example: ...
11
votes
2answers
250 views

can a ColorFunction have side effects?

Can anyone explain this (to me) odd behavior. If I run this code once (fresh kernel) it works as intended. ...
1
vote
2answers
346 views

Using Functions as Arguments to Function

I am trying to make a function like Norm but defined like so: MyNorm[{x_,y_,z_}]=Sqrt[x^2+y^2+z^2]. Mathematica assumes that x, ...
8
votes
2answers
395 views

Generating a position lookup function for an arbitrary list of integers

In my code, I generate a list of integers called numlist. Here is an example numlist: ...
1
vote
2answers
346 views

Piecewise function with a function as argument

I want to define a piecewise function, which has two arguments, one of which is a function of the other's piecewise argument. I am giving an example ...
1
vote
2answers
135 views

How can define a set of nested parameters

I would like to know how I to define a function with a nested set of parameters (or whatever you would like to call it). For example, how would I get the following function ...
1
vote
3answers
777 views

Variables Inside Functions Not Evaluating

x = 5*y function1[y_] := x function1[5] Am I wrong in thinking that function1[5] should equal 25? Instead this comes out. ...
1
vote
1answer
216 views

Calling part of a variable in a user defined function

I have defined a function ...
3
votes
4answers
161 views

Pack Solve results into a vector

I am currently using a really easy function to get the eigenvectors of a corresponding eigenspace: ...
8
votes
3answers
355 views

Where in the documentation can I find a list of function argument types?

Recently, I learned that it is possible to assign "types" to function arguments in the definition of a function. Suppose I have a function stringFun that does some ...
8
votes
2answers
256 views

Manipulating OptionsPatterns[]

How do you combine OptionsPatterns? For example, I would like to have a function that can take both options that I specify, and options for all graphs: ...
18
votes
3answers
362 views

Nested definition: How can I define a function with a passed-in expression?

Here's a simplified version of what I'm trying to do: ...
22
votes
6answers
1k views

Convert an expression to a Function

I need a function which can take an expression and return a pure function based on the symbols in the expression. The symbols might have values so must be protected from evaluation. It is probably ...
3
votes
9answers
1k views

How to find palindromic numbers (Project Euler #4)?

I'm trying to solve the fourth Project Euler's problem with this: ...
4
votes
2answers
165 views

Standardizing a coset table via matrix manipulation

Suppose we have a group $G$ and a subgroup $H$. A coset table encodes the permutation representation of $G$ on the right cosets of $H$. When we want to use these coset tables in calculations, it is ...
5
votes
4answers
596 views

Swap two entries in a matrix

Is there a nice, simple script one can use to swap two entires in a matrix? For example, suppose we have the matrix below: $A=\begin{pmatrix}2 & 4 & 1\\ 3 & 1 & 2\\ 4 & 3 & 1 ...
3
votes
2answers
373 views

Defining a function using Series? [duplicate]

Possible Duplicate: General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it? I need to define a function using the output of series, i.e. ...
4
votes
1answer
176 views

Finding mappings between expressions

Suppose we have an expression of the form: $j=\frac{A\left(t\right)}{B\left(t\right)}=\frac{C\left(s\right)}{D\left(s\right)}$ That is, $j$ can be expressed either as a function of $t$, or as a ...
11
votes
1answer
425 views

Lazy lists of Tuples and Subsets

I'm trying to build a lazy list that evaluates the n'th m-tuple or subset of a given list using Mathematicas ordering without calculating all the Tuples. The purpose is to allow for example the ...
3
votes
1answer
196 views

Evaluation of self-defined functions

I defined a function that I call disc which I want to minimize later. The function is defined as ...
11
votes
4answers
454 views

Assessing argument type in set delayed function definitions

I'm wondering how to properly assess the type of arguments passed to functions defined with :=. I want my functions to be the most efficient, unambiguous and clear ...
10
votes
2answers
448 views

Proper way to add vertices to an adjacency matrix

I'm looking for a robust way to add vertices to a graph by modifying its AdjacencyMatrix. Here's what I have so far: ...
2
votes
3answers
2k views

Passing a matrix as a function argument

I am trying to do the following: ...
3
votes
3answers
157 views

Function[] argument nesting for operations like Select[]

The following code selects a special element from a list thelist = {"this", "notthis"}; Select[thelist, (# == "this") &] What I want is a function which ...
2
votes
2answers
203 views

Working around behaviour of EdgeRenderingFunction

One can make graphs GraphPlot[{1 -> 2, 2 -> 3, 3 -> 4, 4 -> 5, 5 -> 1, 1 -> 1, 5 -> 5}] and one can generalize the input such that one ...
2
votes
3answers
231 views

How to Compute Aggregate Best and Worst Cases for a Large Number of Estimates?

I need to aggregate multiple estimations, but I haven't been able to find a built-in function in Mathematica that aggregates multiple probablity estimations (I am specially interested in estimations ...
4
votes
2answers
2k views

Creating custom functions with multiple arguments

I am hoping that this isn't a stupid question so feel free to vote it for closure. Google failed somehow. I want to define a custom function (more complicated than the usual ...
17
votes
2answers
805 views

Define parameterized function

I would like to be able to define the gain function of a system from its parameters. Specifically, I'd like to define a function that accepts two inputs, call them $b$ and $w$, and returns a function ...
17
votes
3answers
788 views

Using pure functions in Table

I need a table with the elements made of pure functions and list elements. This is a simplified example: I need a list as: ...
4
votes
2answers
267 views

Returning Replacement Rules in a function and using it later on

I would like a function which returns replacement rules as some internal mathematica functions are doing and use the results in other functions. I could not find any information on that and I'm ...
6
votes
2answers
359 views

Passing unquoted strings (poor man's enumeration)

I would like to be able to pass an unquoted string as a parameter to a Mathematica function [that I am writing] and have it show up without evaluation if the string happens to be defined. Thus I would ...
2
votes
3answers
203 views

Ways to change an explicit function into a pure function

I'm trying to use FixedPoint to solve a transcendental equations, but the first argument of the FixedPoint should be a pure ...
16
votes
3answers
560 views

Function that counts the number of arguments of other functions

I have a newbie question: is it possible to write a function that counts the arguments (total and optionals) of a given function? Possibly it should be able to work with built-in and custom functions ...
16
votes
5answers
2k views

The difference between 0. and 0

I have a function for which 0 is a special case: f[A___, 0, B___] := 0 But since I am doing numerics, sometimes in the course ...
2
votes
2answers
122 views

How to evaluate this product

I was trying to evaluate this product $$ \sin (1^\circ) \sin (2^\circ) \sin (3^\circ) ... \sin (88^\circ) \sin (89^\circ) \sin (90^\circ) $$ But I think it got weird results with this ...
10
votes
2answers
905 views

Converting ConditionalExpression to Piecewise

I have Solve[] return a list like ...
35
votes
3answers
1k views

Tiling a square

I wondered if there was a way to automate the process of finding a way to tile a tile into a square. The idea is to represent the tile with a matrix of $0$s for blank space and $1$s for filled spaces ...
9
votes
6answers
2k views

Recursive function with if-statement

I am trying to represent the following function definition in Mathematica: $$\begin{align*} f(1)&=1 \\ f(2n)&= \begin{cases}f(n) & \text{if}\space n\equiv0\pmod{2} \\ 2f(n) & ...
16
votes
9answers
1k views

How do you check if there are any equal arguments(even sublist) in a list?

I would like to set up a function which has to return True if at least two arguments of a given List are equal. So if I give {1,4,6,2} to the function it has to ...
20
votes
4answers
706 views

Can a function be made to accept a variable amount of inputs?

I have a function that takes two inputs and processes them for a single output. What I need is one that can take a varying number of inputs. and process them to a single output. Is this possible in ...
2
votes
2answers
150 views

Is it possible to use PropertyValue to modify properties of Graph objects in a list?

This post can be seen as a follow up to Property assignment on a graph vertex using PropertyValue does not work inside a function. I have defined a function: ...
5
votes
1answer
665 views

Nesting multiple functions of multiple variables

I was wondering how one would go about nesting multiple functions of, say, two variables. The problem comes from trying to implement the Chirikov standard map without using "for" cycles. I found a ...
23
votes
1answer
499 views

How to augment the realm of functions Mathematica thinks it knows how to integrate symbolically

My question involves extending the functionality of Integrate over specific integrals in the most generic manner. Specifically, is it possible to "hack into" ...
0
votes
2answers
194 views

Constraining two points, a specified distance apart, to a line

Suppose that I have two points in the xy plane: pt1 and pt2init. pt1 is fixed in space, ...
26
votes
4answers
598 views

How to make MapAt work with Span?

Span (;;) is very useful, but doesn't work with a lot of functions. Given the following input ...
6
votes
1answer
141 views

Property assignment on a graph vertex using PropertyValue does not work inside a function

I created this function: AddStone[board_Graph, v_, s : white | black | empty] := PropertyValue[{board, v}, VertexState] = s This function should change the ...