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

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2
votes
1answer
116 views

Flat function with repeated sequence

There are functions like Join[ ] that accept a variable number of arguments. Join is a flat function, as the order of arguments ...
16
votes
4answers
6k views

Finding Limits in several variables

Is there a way to find a limit of a multivariable function, like $$\lim_{(x,y)\to (0,0)} f(x,y)$$ with Mathematica? When $f$ is continuous, we can use $$\lim_{(x,y)\to (0,0)} ...
9
votes
1answer
211 views

Creating a NearestFunction that returns an index

I use Nearest repeatedly for large data sets. For example pts = RandomReal[{-1, 1}, {1000, 3}]; Nearest[pts, {0, 0, 0}] I ...
3
votes
0answers
171 views

Mathlink and multithreading

In order to make my computations faster I have developed a C/C++ application calling Mathematica kernel and performing many operations using Mathematica functions for equation solving. Now I want to ...
4
votes
2answers
387 views

Cannot call custom function loaded from script using C/C++ MathLink

I am using MathLink with C/C++ on a Unix system in order to call a Mathematica (version 9) function and get the result. The function I need to call is a personal function of mine ...
9
votes
1answer
247 views

Apply a Function Pairwise [duplicate]

I'm new to Mathematica I'd like to apply Mean pairwise to a list to achieve the following. ...
1
vote
1answer
168 views

How to send a function definition to MathLink from C/C++?

In this tutorial some MathLink concepts are introduced. At page 33 in the last lines the author is talking about sending to MathLink a function definition like ...
6
votes
1answer
116 views

How does `LongestCommonSubsequence` work?

When I recently came across this posting about LongestCommonSubsequence I was curious about how the function worked. ...
15
votes
2answers
269 views

What are Root objects with multiple polynomials?

In Mathematica 9 a new flavor of Root object with multiple polynomials was introduced. For example, ...
10
votes
1answer
131 views

How do I expand StirlingS2[n, 10] in terms of elementary functions?

I know that it is possible to expand StirlingS2[n, 10] in terms of elementary functions of n. I tried ...
13
votes
1answer
316 views
2
votes
1answer
142 views

Cannot run Mathematica C-interfacing examples 'factor'

I am trying to run a Mathematica example concerning Mathematica interfacing issues with C programs. In particular I am trying to call a Mathematica function from C. Example ...
2
votes
3answers
450 views

Use elements of Array inside function definition

I'm trying to define a function which modifies and sums over the elements of an array. Here is a very simplified version. myF[kmax_] = Sum[v[[k]]/k, {k, 1, kmax}] ...
0
votes
1answer
62 views

Don't pollute outside context when solving equation from the outside

This code works fine only if a is not defined in the outside context: ...
1
vote
2answers
96 views

Calling blank arguments using enclosing functions

Is there a way to call a function and have that function use an argument defined in an enclosing function? e.g., ...
11
votes
1answer
1k views

Write C/C++ programs calling Mathematica functions

I need to write a C/C++ program and call some functions in Mathematica especially those like Solve or NDSolve. The problem is ...
2
votes
2answers
660 views

distance between two curves

I try to compute the distance between two curves. I use the EuclideanDistance to do that. Here my code: ...
3
votes
2answers
531 views
3
votes
2answers
150 views

Generating a list of pure variables

I want to pass a list of pure variables to a function, in which the ordering of the variables matters. For instance, if I want a palindrome, my function might be: ...
0
votes
1answer
331 views

Can Mathematica check if two expressions give the same output for integer input?

Let me give the background for this question. I'm using WebAssign to assign homework problems, and WebAssign has a built-in mechanism which can grade problems using Mathematica commands. For ...
2
votes
5answers
418 views

How to leave function unevaluated programmatically?

Is it possible to write a function in such manner, that it can be either evaluated or left unevaluated? This is a general question. Sample below is just a sample. No need to find solution for this ...
4
votes
1answer
170 views

Create string from character code

Is it possible to convert a charcode/keycode to a string? I want to do this to create variables in a generated equation.
0
votes
1answer
114 views

Can I force a function to quit and return some value after a certain amount of time has passed during its evaluation?

Imagine I provide some random input to function like FindInstance[], and I observe that, despite the existence of good solutions, the function will, with some ...
1
vote
1answer
1k views

How do I define the domain of a function?

I have a function of two variables, f[x_, y_], and I would like to restrict the domain to values of x and ...
1
vote
3answers
556 views

Sqrt — how to get negative branch?

One of the many attractions of Mathematica is that integers are generally treated as exact symbolic entities, and not just as numbers. I was just playing with Sqrt, and was puzzled by what appeared to ...
7
votes
2answers
516 views

Function Interpolation with Automatic / Algorithmic Values Mesh

I have an underlying function f(x,y,z) that is computationally intensive, but is smooth and continuous. I'm needing to find the function values along a line in xyz. Currently, I'm calculating f at ...
1
vote
1answer
369 views

Using undefined function in an expression

I want to use undefined functions in expressions to be simplified. For example. I want mathematica to simplify this input $(f^{\prime\prime}(t),g^{\prime\prime}(t))\cdot (-g^\prime(t),f^\prime(t)) $ ...
1
vote
1answer
915 views

3D plot of two 2D functions

I would like to plot two 2d functions in a 3d coordinate system. Examples are z = x^2 and z = y^2. Each function has one ...
2
votes
2answers
119 views

changing a symbol into a function variable

Struggled for a while on this problem and hopefully you can help... I have a mathematical expression that currently has a symbol where I used to have a function variable. How do I make the symbol ...
9
votes
1answer
552 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 ...
4
votes
3answers
1k views

How to prove an expression by method of mathematical induction?

I want to prove the expression $$1^2 + 2^2 + 3^2 + \cdots + n^2 = \dfrac{n(n+1)(2n+1)}{6}$$ by method of mathematical induction with Mathematica, but I do not know how to start. How do I tell ...
0
votes
0answers
32 views

How does Plot evaluate its argument? [duplicate]

I have a list of about twenty InterpolatingFunctions that I'd like to plot. They are interpolations from experimental data (frequency spectra between 100 and 5000 ...
5
votes
5answers
1k views

Series expansion in terms of Hermite polynomials

I am trying to expand a polynomial in terms of orthogonal polynomials (in my case, Hermite). Maple has a nice built-in function for this, ChangeBasis. Is there a ...
1
vote
1answer
801 views

Plotting a complex function [duplicate]

What does it mean if this message appears: {Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0,Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0} must be a list of equalities or ...
12
votes
1answer
263 views

What's a good style for inheriting Options[] of built-in function?

Options[myPlot] = Options[Plot]; myPlot[args___] := ... When defining a "wrapper" function like the above, I'd like it to inherit the ...
2
votes
1answer
134 views
0
votes
1answer
103 views

Should Read[] not close its Stream? [closed]

I read a record from a file. Read[file,Record]; It reads and opens a stream. Should Read not close its stream after ...
2
votes
2answers
272 views

Position function not always retuning an answer even with no apparent problems

I'm having some problems with Position. Sometimes it will give an empty list instead of the actual position of the element I am looking for when that element is ...
3
votes
3answers
210 views

Alternative to using global variables in functions?

Often times I find myself using unevaluated variables (i.e. they show up blue) as dummy variables in whatever I'm returning such that I can evaluate them as needed later on. A simple example is as ...
18
votes
3answers
2k views

Plotting piecewise function with distinct colors in each section

I have a piecewise function that I would like to plot but I was wondering if it is possible that each part of the function that is plotted when its corresponding condition is true be plotted with a ...
12
votes
1answer
266 views

Is there a summary of answers Head[] can give?

Sometimes you need to check for the type of an expression. You use Head[data] to get answers. Some data: ...
2
votes
0answers
124 views

Is there documentation on the comparative performance of Mathematica functions? [duplicate]

Recently I have been solving some Project Euler problems. I find there are always several ways to do the same thing. For example, one could join two lists like this: ...
0
votes
1answer
65 views

how to generate functions with changing array size?

I want to write a function in Mathematica which has two inputs 'n' and 'd', and the output should be (in Latex notation) $$F(n,d) = \sum_{i[1],...,i[n] =0; i[1]+...+i[n]\leq d}^{d} C[i[1],...,i[n]] ...
9
votes
2answers
313 views

How can I get the right hand side of a delayed expression?

Imagine there is a given function f, defined with SetDelayed, say f[x_] := Sin[x]^2 + Cos[x]^2. Is it possible to get rhs of ...
0
votes
2answers
331 views

Expansion in Basis Functions

I am trying to create an expansion of the form f[x,y]->Sum[Cn[x] y^n,{n,1,order}] To replace the function f by the ...
6
votes
3answers
335 views

Permanent minors

The function Minors yields the minors of a matrix. Is there a function that yields the permanent minors of a matrix?
0
votes
1answer
181 views

Solving a differential equation for a variable in a function

This may sound like a very trivial question, but I need to solve a differential equation as follows: ...
3
votes
2answers
356 views

What is the command to find function invariant?

What is the command to find function invariant? http://demonstrations.wolfram.com/AFunctionInvariantUnderAGroupOfTransformations/ what is algorithm it use to calculate this? Edit there is a book ...