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.
10
votes
3answers
444 views
What is Mathematica's equivalent to MATLAB's filter function?
The MATLAB code
filter(0.5,[1, -0.5], [1:10])
is equivalent to
Rest@FoldList[(#1 + #2)/2. &, 0, Range[10]]
I don't ...
8
votes
2answers
103 views
Possible to scope an anonymous function within Module?
This is my first question. I'm fairly new to Mathematica and completely new to SE, so I apologize if this question is trivial.
I'm working on a problem that requires a function to be redefined ...
2
votes
3answers
111 views
Defining a function to determine when convergence is guaranteed
I'm investigating how many iterations are needed for a particular orbit to reach a fixed point of a function. Since I have many functions to test, I want to define a function
in Mathematica that will ...
3
votes
2answers
227 views
Why does the first derivative of a piecewise continuous function have discontinuities?
I have this piecewise continuous function which is also continuously differentiable over time :
...
0
votes
1answer
77 views
Strange function definition result [duplicate]
I'm relatively new to Mathematica, and I'm trying to define a function f(k) that would do the following:
For any positive integer $k$, a finite sequence $a_i$ of fractions $\frac{x_i}{y_i}$ is ...
2
votes
2answers
99 views
Defining a function by pieces using list of interpolated functions in order to use `FindRoot`
I have two lists with the interpolated functions
...
15
votes
4answers
242 views
Enforcing correct variable bindings and avoiding renamings for conflicting variables in nested scoping constructs
Using global variables the following turns an "expression" into a Function:
expr = 2 x;
Function[x, Evaluate[expr]]
Of course ...
5
votes
1answer
138 views
How to find the name of the current function
I would like to know the name of the current function from within that function. For example, consider the following code
...
1
vote
0answers
73 views
How can I obtain the function described by given set of central moments?
I want to investigate how my function P behaves with different probability functions rho as input variables.
This means
...
1
vote
1answer
108 views
Function definition and delayed assignment
I need to define the following function
MyWavelet[n_]["PrimalLowpass", prec_ : MachinePrecision] :=
Table[(-1)^(j - 1) h[[2*n - j]], {j, 0, 2*n - 1}]
which ...
4
votes
4answers
212 views
Differentiating space curves
I'm trying to do some very basic differential geometry of space curves. For example, a space curve $\gamma:\mathbb R\to\mathbb R^3$ has unit tangent and normal vectors given by
...
2
votes
4answers
304 views
How to write a differential operator in Mathematica
I have a very basic question. I am trying to code the LHS of the differential equation:
...
3
votes
1answer
78 views
Using NestWhileList to determine smallest prime value in series
I have a function recursively defined as follows:
$a_{n+1}-1=(a_n-1)\times lpf(a_n)$, whe $lpf(x)$ is the least prime factor of $x$.
Now, given an initial value of $a_0$, I would like to find the ...
4
votes
1answer
136 views
Module with “local functions”
I am trying to use a Module having "local functions", i.e., those which I need to define only inside this module.
So I tried this:
...
4
votes
3answers
99 views
Creating a nonperiodic function in mathematica
I want to create a non-periodic square wave with values of 1 and -1(not necessarily alternating).
For e.g. I want to convert an arbitrary array like {1,-1,-1,1,-1,1,-1} into a function.
I tried ...
1
vote
1answer
66 views
Confirming the existence of a function related to a matrix
Is it possible to get an answer to the following question in Mathematica?
Let $M$ be a $n$ by $n$ matrix, is there a function $m:\mathbb{N}\times \mathbb{N}\rightarrow \mathbb{Z}$ such that ...
0
votes
1answer
86 views
How could we define a function recursively?
Let us first consider the constructon of the following simple iteration
...
3
votes
1answer
114 views
Downvalues vs. Scoping for Functions
Regarding my recent question on using a default value for a function argument when a pattern was not met yielded some interesting answers, but the general consensus was "Yes this can be done, but ...
0
votes
1answer
175 views
How do I make function A create and return function B?
My basic need is I have to take lots of data and other information and assemble it into a function (static parameters). I then need to call the function many times for numerical results for many ...
2
votes
2answers
114 views
How to achieve Set+Part like behaviour in custom Set function?
So I've been toiling away on my DataFrame package. I've been trying to get Set to work with it, but it seems it either can't be done (ie via ...
1
vote
1answer
106 views
Creating an array eval [closed]
How can I create an one dimensional array (a vector) evaluating a function of two variables? I know how to do it with one variable:
Array[f, n, {a, b}] generates a ...
10
votes
1answer
113 views
Multiple templates for a single user-defined function
How do I use the ::usage tag to allow the Mathematica v9 front end to know that there are multiple ways to call an overloaded function (a function that can have ...
3
votes
1answer
90 views
Is it safe to assign a variable and function of the same name for different things?
I'm writing out a notebook that goes through the van der Waals Equation of State for gases, and I run into a situation where I want to assign (simplified) Tc[b_]:=5b, use that to solve for b in terms ...
0
votes
1answer
299 views
How can I make a plot of the Higgs potential?
I was wondering, how would could I make a drawing of the Higgs potential aka "mexican hat potential". I am quite new to Mathematica and don't know where to look to learn how to implement such a ...
6
votes
4answers
176 views
Function argument to default under certain condition
Inspired by this and this question (and how I handle this in practice), what is the best way to default a function value when a certain condition is met?
For example, if a function is defined as:
...
2
votes
1answer
109 views
Can my permutations function be defined using iteration?
I have two functions, tuples and perm. They are similar.
...
2
votes
0answers
62 views
From notebook,how can I change variable value with in .m file dynamically?
I wrote a function named Testing.
...
3
votes
2answers
113 views
Apply UpValues before Listability
I'm trying to modify Plus but am running into trouble with it being Listable:
...
3
votes
1answer
70 views
Values set using SetOptions are staying in the kernel, beyond the necessary time [closed]
I wrote a function name as functionTest and also mentioned default Options.
...
6
votes
1answer
276 views
How can I define a function that can accumulate its parameter?
For example, write a function add:
add[3] return 3
add[4] return 7
add[10] return 17
10
votes
2answers
204 views
Functions that remember their values
Can someone explain what is going on with the following ...
func[y_] := func[y] = (Print["Hello world !!!"];)
func[1]
Hello world !!!
...
1
vote
1answer
144 views
Fitting parameters of user defined function returning discrete values
So, I'm fairly new to Mathematica (apologies in advance for the noobiness), and I'm having some problems regarding fitting the parameters of a user defined function to data. I'll give a representative ...
0
votes
1answer
138 views
How to write case, in piecewise function, correctly [closed]
I want to plot graph of this piecewise function in Methematica:
$f: [0, 1] \mapsto \mathbb{R} $
$f(x)= \begin{cases}
\frac{1}{x - \frac{1}{3} } & \text{ if } x \in [0, \frac{1}{3}> \newline
...
6
votes
3answers
210 views
3
votes
2answers
227 views
Ways to plot interpolating functions more economically?
I am interpolating a lot of data over geographic coordinates obtained via GPS, and frequently I need to plot these interpolated functions together. For example, I may have an interpolated elevation ...
3
votes
0answers
43 views
How to influence Suggestion Bar in your package/code [duplicate]
Possible Duplicate:
Is it possible to customize the Suggestions Bar?
I have written a little code (like a minipackage) of different functions. In using my code, the user typically starts ...
0
votes
1answer
106 views
Creating Recursive Sequences
Quite a simple question, I reckon, however, even quite an extensive search hasn't helped me.
I want to define a recursively defined sequence that starts with defined ...
3
votes
1answer
128 views
Feedback on my Subscript code
I have written a code, and I need a little feed back..
I want to make the Subscript distributive across (1) addition and (2) multiplication to mimic short-hand for ...
1
vote
3answers
152 views
More than one expression in the Table[] command?
I would like to construct a Matrix using the Table[] command. The issue is that I would like to use more than one expression for it. What I need to obtain is something like this :
...
2
votes
2answers
137 views
Hiding certain user-defined functions in front-end autocompletion
I have written an elaborate code that contains a collection of functions for the user and a bunch of auxiliary functions whose existence I would like to hide away from the user. I've written my code ...
4
votes
2answers
158 views
Pattern matching repeated structures with named subexpression components
I am trying to write a function with a pattern that tests its arguments for a particular structure. But in that pattern I'd like to name a subpattern to make it easier to exract and operate on.
The ...
7
votes
7answers
498 views
Can my color function be written more simply?
The code shown below works well, but I think the pure function I'm supplying to the ColorFunction option could be more elegant. How can I simplify it?
...
0
votes
0answers
52 views
Enable syntax-coloring on user-defined function [duplicate]
Possible Duplicate:
Syntax highlighting for your own functions
I have defined a function myIntegrate that carries out a routine similar to Mathematica's ...
3
votes
3answers
105 views
How to identify patterns in a tensor-polynomial and replace appropriate symbol?
I want to write a function tensorReplace[input] that takes a tensor polynomial in $r_i$ such as $r_i r_j r_k+r_i q_j q_k +q_i q_j q_k$ , and replaces each monomial ...
2
votes
1answer
117 views
Rookie mistake in defining a function with Modules?
I can't figure out what's wrong with this piece of code. I'm trying to define a function that counts the occurrences of x, y and ...
7
votes
4answers
292 views
Is there a concise form of Which or similar conditional?
Suppose that I want to write a function fun that takes an Integer num as input, and returns ...
10
votes
0answers
131 views
func::usage needs to be run twice?
There is an annoying problem that I can't figure out why it's happening. I have defined a usage for a my function tensorA:
...
7
votes
3answers
138 views
How to set a TraditionalForm output for a symbol
How do I set a TraditionalForm output for a particular symbol/function?
In particular I would like my user-defined symbol ...
1
vote
2answers
166 views
Composing two functions in Mathematica [duplicate]
Possible Duplicate:
Composition of mappings not working as expected
I am new to Mathematica and I am having trouble defining a certain composition of functions.
Let ...
2
votes
1answer
92 views
How to override `?NumericQ`
I have a function myFunc which I is to be displayed cleanly if arguments are symbolic, but which can also be numerically evaluated. I do this by defining a ...
