Questions about Mathematica's functional programming style, including the use of pure functions (Function[], #, &) and functions such as Map, Apply, Nest, and Through.
3
votes
1answer
108 views
Why is this code in functional style is slower than procedural style?
I know that in Mathematica a functional programming style is often more efficient than procedural style programming using For loops. But the code shown below seems ...
0
votes
0answers
64 views
How can I get tabular output for the results of my simulation? [closed]
I have code that simulates a simple Markov Chain and looks like this:
...
12
votes
2answers
279 views
Going full functional (Haskell style)
I'm trying to define some notation so that Mathematica code would be more functional, similar to Haskell (just for fun): currying, lambdas, infix operator to function conversion, etc.. And I have some ...
0
votes
1answer
151 views
Arbitrary depth patterns/rules
Temporary message: I am now really confused. I am not sure how using Power and Unevaluated together works in the examples below.
While answering this question, I stumbled upon the following.
We ...
1
vote
2answers
99 views
Computing distance matrix for a list
Using functional programming in Mathematica, how can I compute a distance matrix for every element in a list of matrices... The distance would be computed between the item in the list and a "target ...
1
vote
1answer
82 views
given n lists, get list of applications of function to n-tuples
Is there a built in function or an easy rule to do the following transformation?
H[{A[0], A[1], ...},{B[0], B[1], ...},...]
into
...
8
votes
4answers
199 views
Transform a list of functions to a composition
How do I apply a list of functions in a nested way?
Example:
functionList = {f1,f2,f3}
RequiredCommand[functionList,Pi]
such that the required command returns
...
0
votes
0answers
299 views
Jacobi eigenvalue and eigenvectors algorithm
Suppose we have a symmetric matrix with dimensions n x n. I need to find the eigenvalues and eigenvectors of this matrix using the Jacobi method. I wrote this code:
...
15
votes
3answers
521 views
Programming a numerical method in the functional style
I am new to Mathematica and I would like to learn a bit more about functional programming.
At the moment I have assignments like programming different numerical methods (for integration: ...
4
votes
2answers
115 views
Update a function avoiding infinite recursion
I am quite new to Mathematica and not completely familiar with functional programming. I am currently working with a function (call it foo) and wish to change its behaviour, for example, by adding 1 ...
0
votes
1answer
195 views
How can I define a Step-Wise function in Mathematica (Not using Heaviside Step Function)? [closed]
I need to define a function, which has very different behaviour in different regions. There are about 13 different regions. A sample of my function is the foloowing table:
I want to define it as a ...
2
votes
3answers
106 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 ...
2
votes
1answer
107 views
Issue with ListConvolve
I am a new Mathematica user, learning the intricacies of functional programming. I have issues withe applying a function over a moving list. My function seems to work and give correct results but it ...
4
votes
4answers
224 views
How to transform Do loop to more efficient codes?
I'm new to Mathematica. Here is my original program: How to rewrite the Do part?
...
5
votes
2answers
174 views
Variant of the cutting-stock problem in Mathematica
I'm pretty new to Mathematica and am trying to learn to solve problems in a functional way. The problem I was solving was to list the ways in which I could sum elements from a list (with repetitions), ...
4
votes
4answers
204 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
...
7
votes
2answers
234 views
Feedback on Functional Programming: Propagation of uncertainty
Lately I've been trying to use functional prgramming and tried to implement the gaussian propagation of uncertainty (without correlation) in an elegant way, here is the outcome:
...
2
votes
1answer
104 views
Can my permutations function be defined using iteration?
I have two functions, tuples and perm. They are similar.
...
24
votes
3answers
274 views
FoldWhile and FoldWhileList
Mathematica has had NestWhile and NestWhileList for some time. But, to date, it has not implemented a built-in ...
2
votes
0answers
60 views
From notebook,how can I change variable value with in .m file dynamically?
I wrote a function named Testing.
...
6
votes
3answers
199 views
10
votes
4answers
490 views
How to write this without For loop
Suppose I have a few lists of numbers and want to exponentiate element-wise, then sum up everything into a polynomial.
For example, if I have
...
0
votes
1answer
189 views
How can I improve my code with efficient mathematica built-in functions?
I have written a module for my assignment like below.
V[n + 1] = rk[x[n], y[n] ,z[n], V[n]];
vs = V[n].V[n+1];
V[n + 1] =
I want to modify it with efficient ...
6
votes
1answer
120 views
map over list of functions
I would like to convert a list of n complex equations to a list of 2n real ones. At the moment I am doing it like this:
...
4
votes
1answer
108 views
Functional Programming: modify EdgeList based on condition
I have a simple functional programming question: I have a simple EdgeList defined in Mathematica, I would like to modify the value of certain element of the list based on a condition.
I see how to ...
14
votes
3answers
424 views
How can I improve my code for drawing a tree?
This code draws a tree, but it's not in the functional style.
...
5
votes
3answers
144 views
All values for a function with two arguments without Outer
Given two lists $l_a = \{a_1, a_2, a_3\}$, $l_b = \{b_1, b_2, b_3, b_4\}$ and some function $f$ accepting two arguments, how can I produce a list of all values $f(a, b)$ for $a\in l_a$ and $b \in l_b$ ...
4
votes
2answers
155 views
How can I improve this trial division procedure?
My background is procedural programming, so I find this construction quite natural. Is there a way to get rid of the While?
...
4
votes
6answers
172 views
Filter list with different list in it
I have a list like:
{{{4, 14}, 1}, {{4, 15}, 1}, {{4, 16}, 1}, {{4, 17}, 1},
{{4, 18}, 1}, {{4, 14}, 3}, {4,15}, {{4, 16}, 2},{4,18}}
Now I want to ...
0
votes
1answer
99 views
Iterative Function Mapping [duplicate]
Possible Duplicate:
How to nest my own “times” function to get powers
What I want to do is something like :
Sin[...Sin[Sin[Sin[Sin[x]]]]]
Basically, ...
2
votes
0answers
77 views
Evaluating a function on permutations of its arguments
Say I have a function "temp" of $n+1$ variables, $y,z1,z2,z3,...,zn$. I want to test if my function has certain symmetries like swapping $y$ with square of any $z$, swapping any two of the zs, ...
2
votes
1answer
119 views
#[[1]]//FullForm = 1?
I have a set of symbolic algebraic expressions that I'm trying to get some speed into. To illustrate the issue, I'll use a simple form like { k0 X, k1 Y, k1 Z}, ...
2
votes
1answer
121 views
Converting expressions into functions
I have defined an expression, such as
a = x
I would like to convert this into a function, such as
f[x_]:=x
However, in my ...
1
vote
4answers
136 views
Order of operations for the Table function [duplicate]
Possible Duplicate:
Using pure functions in Table
I have run into a situation that I do not understand when trying to generate a nested list of pure functions. I have the following code.
...
7
votes
3answers
329 views
Rewriting For loop to FoldList or similar
In CrossValidated, the answer to a question on prediction of number of viewers of Gangnam Style is given in R. I have mapped the answer directly to Mathematica:
...
12
votes
5answers
565 views
How to improve this code for solving the “Mr.S and Mr.P” puzzle?
Mr.S and Mr. P puzzle — "Formalization of two Puzzles Involving Knowledge", McCarthy, John (1987)
We pick two numbers $a$ and $b$, such that $a\geq b$ and both numbers are within
the range ...
4
votes
3answers
279 views
4
votes
2answers
175 views
Define product derivative
How do I define the $n$th product derivative of a function in Mathematica?
The first product derivative $f^\ast$ of a function $f$ is
$$
f^\ast(x)=\exp\left(\frac{f^\prime(x)}{f(x)}\right)
$$
The ...
6
votes
4answers
402 views
Alternatives to While Loops?
I am using Mathematica to run a probabilistic simulation. Essentially, I have a list of members of a population (they only have one, numerical, attribute, so it's just implemented as a list of ...
11
votes
2answers
199 views
From iterative to functional
How to write this small piece in a functional way (ie. without state variables)?:
...
4
votes
1answer
169 views
Timing differences between multiple executions of identical code
I have a
list of pairs of numbers and I'd like to change the sign of the second element in each pair i.e. $(a,b)\rightarrow (a,-b)$.
I'm sure there are many ...
1
vote
2answers
133 views
How to create a list of variable names to some function of that variable
For example, for a single variable I can write
Print[Unevaluated[a], "=", f[a]]
But if I try the next thing I'd think of doing, assuming I want a list, it ...
3
votes
2answers
118 views
How do I convert an argument list to a list of arguments? [closed]
I think this is a basic question, but I am having difficulty finding the answer in the documentation. Thread is not what I am looking for, I think.
Suppose that I ...
1
vote
2answers
103 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 ...
10
votes
4answers
229 views
Thread a function over a list and with a non-atomic 2nd parameter?
From the documentation, Thread's behavior on functions where the first parameter is a List and the second is an atomic expression, is this:
...
23
votes
12answers
816 views
Map a function across a list conditionally
It seems that this is a really basic question, and I feel that the answer should be obvious to me. However, I am not seeing. Can you please help me? Thanks.
Suppose I have a list of data ...
0
votes
2answers
112 views
About minimizing calculations when using ComposeList
I have a lot of functions to use in a iterative way, and I need some of the calculation results. For example:
...
6
votes
5answers
214 views
How to nest my own “times” function to get powers
I have a "times" function. I'd like to create a power function using it. It should look like this for an 6th power:
...
6
votes
0answers
110 views
What are some general strategies to avoid using For loops? [duplicate]
Possible Duplicate:
Iterating over lists in Mathematica
While there are some cases where a For loop might be reasonable, it's a general mantra – one I ...
14
votes
3answers
348 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:
...
