Questions about the use of built-in Mathematica functions, including pure functions.

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5
votes
3answers
217 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 ...
3
votes
3answers
906 views

Solve with v9 (issues with Subscript, Overscript, Superscript etc)

The way Solve works has changed in v9 ... in essence, to get the answers that one obtained under v8, one now often has to specify a lot more information about all ...
4
votes
1answer
159 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 ...
1
vote
0answers
33 views

Define a second name for a function [duplicate]

I'm working with an own package of functions. During development I noticed, that my naming scheme is not that clever; for example some of my functions are starting with capital letters. But I have ...
2
votes
1answer
213 views

Print out all functions in Mathematica

Sometimes I only remember parts of a function name and I want find that function name quickly, and if I search in the document center, it will give too much informations related to that and difficult ...
8
votes
1answer
284 views

Optimizing the performance of an algorithm

First - a bit of an introduction. If you're only interested in the code, you can skip this section. The following question is drawn from Dennis E. Shasha's Puzzling Adventures, and is listed under ...
8
votes
6answers
853 views

Manipulate and Turning Expressions into Functions

I've been trying to use Manipulate to do interactive plotting, but I've been running into a few problems with saved expressions. I have an expression saved as "func" and I want to work with it and ...
2
votes
1answer
911 views

How to export/import function values [duplicate]

I have a function with two variables: f[x_,y_]:=f[x,y] = ... I calculated some values (they are fractions like 435345345/3424242424) and would like to store the ...
5
votes
2answers
602 views

How to declare a function of variable?

In my program, there are many functions relying on spatial coordinates: x, y, and z, which are also functions of time t, i.e., composite function. I need to differentiate some functions for example f: ...
7
votes
2answers
137 views

Method that can be used to collect the variables of a function

Suppose we have a function f[x, y, z] and we want to get all its variables Sequence[x,y,z], what method can we use then? The ...
8
votes
2answers
205 views

How do I write a function that can be used in a rule to modify both sides of an equation? [duplicate]

I sometimes need fine grain control over equations in Mathematica in order to help me understand how to solve a problem manually. A greatly simplified example of a session might be something like ...
6
votes
4answers
638 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
138 views

Plot[] breaks behavior of custom data handling function - Recursion

I am working on a utility to analyze a set of data. I want to process the data with a sliding window, in such a way that there is an output associated with each sample of data. To start, I have a ...
10
votes
1answer
702 views

What is the difference between prefix/postfix notations and map?

I am new to Mathematica and just experimenting with the different programming constructs. I have been looking at Map and how to evaluate a function for a list of ...
2
votes
0answers
87 views
2
votes
1answer
174 views

How can I calculate a limit with a free variable?

For example, when I evaluate Limit[(1 + x^n + (x^2/2)^n)^(1/n), n -> Infinity] Mathematica does not output any result. When I evaluate ...
3
votes
1answer
241 views

Help on how to write a function to be used with NMinimize

I need some help to write a proper function to be used as a parameter on NMinimize. Here is the code of the function to be minimized (Please correct, optimize and rewrite the code if you want to - I ...
8
votes
3answers
696 views

FullSimplify does not work on this expression with no unknowns

I can't reproduce this simple example from Habrat, 2010 ("Mathematica : a Problem-Centered Approach"). It is supposed to demonstrate the functionality of ...
8
votes
2answers
365 views

Tally repeated evaluation of function

How can I tally the result of repeated evaluation of a function? n=100000; f[]:=RandomInteger[{1, 4}] Tally@Table[f[], {n}] When ...
0
votes
1answer
2k views

Given x[u,v], y[u,v], and f[x,y] how do I find D[f,x] in terms of u,v?

I have two functions x = x(u,v) and y = y(u,v). The chain rule says that for a function f(x,y), df/dx = df/du du/dx + df/dv dv/dx, and similarly df/dy = df/du du/dy + df/dv dv/dy. How do I get ...
10
votes
2answers
354 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 !!! ...
4
votes
0answers
134 views

What is the difference between Block and Module? [duplicate]

Possible Duplicate: What are the use cases for different scoping constructs? I don't understand the difference between the Matheamtica functions Block ...
3
votes
1answer
262 views

Efficiently finding the maximum value of a column in a matrix

Imagine I have a matrix of the following form: TestArray = $((a_1,b_1,...),(a_2,b_2,...),(a_3,b_3,...),...)$, where a specific example might be: TestArray = ...
2
votes
1answer
168 views

writing a function using multiple variables

I am fairly new to Mathematica and am trying to write a function for the equation: xx = [x/(Sqrt[h^2 + d^2 + y^2]))*(Sqrt[h^2 + (d + yy)^2]) where h, d are known ...
28
votes
2answers
882 views

Strange ::usage behavior in v9

Bug fixed in 9.0.1 Something has gone wrong with usage in Mathematica 9. Would someone tell me how to fix it? I define a function ...
20
votes
1answer
387 views

What is PointForm?

I stumbled across a function called PointForm but the only documentation I can find is the pop-up line offered by autocomplete, which contains the same information ...
12
votes
1answer
332 views

Overloading second argument of CountryData

For convenience I'm trying to add an extra property to CountryData ...
6
votes
1answer
164 views

FunctionTreeForm

I'd like to implement a function FunctionTreeForm which takes an arbitrary complex function and renders all the captionable subfunctions in a TreeForm. Explanation If we take e.g. a function: ...
2
votes
1answer
173 views

Representation of product with exclusions

Is there a nice way to define output formatting for my expression, a product from n = k to j with ...
7
votes
2answers
2k views

How to study asymptotic behavior, built-in functions

My question is as follows. Suppose we have a function $f(r)$ and we want to study its asymptotic behavior at infinity ($r\rightarrow \infty$). For example, the function may reduce to $-\frac{a}{r}$ or ...
2
votes
1answer
160 views

Mathematica crashes after evaluating a call to a user-defined function [closed]

I have recently installed Mathematica 9 on my macbook pro, os version 10.6.8. As you can see in the minimal example notebook you can download here: ...
11
votes
4answers
378 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 ...
14
votes
4answers
3k views

How to modify function argument?

Usually in programming languages, function arguments are normal local variables, which can be modified. Is this not true in Mathematica? ...
1
vote
1answer
156 views

need help with finding right syntax for an IF statement

I am working with two multi-variable functions A and B. They depend on some counting factors ...
12
votes
4answers
1k views

Pure Functions with Lists as arguments

Assuming I have two function: example 1: add[{x_, y_, z_}] := x + y - z add[{1, 3, 5}] If use pure function,I know I can write it as : ...
-1
votes
1answer
214 views

Some Problem with WhenEvent! [closed]

Anyone knows what's the problem with the following code and how can I fix it? I am not sure that I wrote the WhenEvent section correctly. By the way, I want to solve the equations and then plot y vs. ...
0
votes
2answers
150 views

How to obtain a smaller-sized output from Solve

I am solving a system of 15 simultaneous linear equations using Solve. On running the code, I get a message saying "A very large output was generated" with options ...
0
votes
1answer
126 views

Why am I not getting Indeterminate for f[1] when f[x_] = (x - 1)/(x - 1)? [closed]

In Mathematica 9 If I write: f[x_] = (x - 1)/(x - 1) I get 1 And if then I write: ...
1
vote
1answer
169 views

Random sample with gap sizes

Lets say I have 101 instances of data with multiple attributes. In particular case, one attribute has 7 unique values. I want to get ...
54
votes
2answers
6k views

What is the difference between Reduce and Solve?

Solve and Reduce both can be used for solving equations. Just by working with them, I know there are some differences between ...
4
votes
1answer
463 views

Using DistributionFitTest on custom distributions in Mathematica 8

I originally posted this question on Stack Overflow, but I didn't get any answers, and I'm hoping to have better luck here. I'm trying to compute the goodness-of-fit of a bi-modal Gaussian ...
8
votes
3answers
416 views

Radon function result's repeatability

Bug introduced in 9.0.0 and fixed in 9.0.1 I want to get a Hough transform of some edged image. When I compare the same transformation on the same image I got different results. ...
9
votes
2answers
351 views

Define Log so that negative reals evaluate on lower edge of branch

I need to get Mathematica to evaluate the logarithm of a negative real number using the lower branch instead of the upper branch, so that while ...
3
votes
1answer
3k views

Filtering Lists in Mathematica [duplicate]

Possible Duplicate: Select/Delete with Sublist elements? I need help in filtering long lists of x,y coordinates.Lets use the following list as an ...
6
votes
3answers
283 views

How to rename a built-in function?

I want a built-in function renamed without loss of any properties, I want the shorter name to appear in all results and to be recognized as input. Is it possible?
-2
votes
1answer
196 views

How to pass arguments between functions

I have two Functions, f[] and g[]. f is passed some values ,say ...
1
vote
2answers
245 views

While-Loop Linear Projection

I'm would like to do a linear progression for a recursive relation of a consumption function. Combining my program skills and my sparse knowledge of mathematica, I was thinking about doing it in a ...
4
votes
6answers
227 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 ...
11
votes
1answer
657 views

user defined functions, how to save them for future use?

I need certain user defined functions over and over. I was wondering how can I define and where and how to save them such that each time I start a notebook, these functions are available and need not ...
0
votes
1answer
2k views

Loops and subroutines [duplicate]

Possible Duplicate: Alternatives to procedural loops and iterating over lists in Mathematica I am new to Mathematica and not familiar with functional programming. In particular, I have no ...