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

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2
votes
2answers
173 views

Graphical solution of a a two-variable system containing an equation and an inequality

I'm currently studying atmospheric-gravity waves and their dispersion relations. I want to have look at values of $(x,y)$ that solve the following system : \begin{equation}\label{}(1) \left\{ ...
2
votes
0answers
99 views

Find eigenvalues without filling the matrix

Is it possible to find eigenvalues of a matrix without filling it? The matrix elements are given by a known function f[p1,p2]. This is relevant for a matrix too ...
1
vote
1answer
76 views

Get subgraphs: communities of graph g

I have a graph g. I want a set of graphs c which holds the community subgraphs of g. I ...
1
vote
2answers
142 views

function of derivative of a function

I know a similar question is answered somewhere, but it doesn't work for my case for some reason. I have the following problem in Mathematica. I want to compute f[h[x]]= x^2 + D[h[x],x]. Here, h[x] ...
2
votes
1answer
191 views

Why evaluation doesn't fail if arguments are invalid? [duplicate]

Sorry for a noob question, but this is something that I wonder about each time I work with Mathematica. Coming from standard programming languages (Python and Java), I expect my functions to fail ...
0
votes
1answer
637 views

Discrete peaks to curve via Voigt summation

I have two data sets. One is an experimental recording of an absorption spectrum, composed of regularly spaced (wavenumber, intensity) coordinates with a fine wavenumber resolution, thus making ...
1
vote
1answer
191 views

Defining arbitrary order derivatives function [duplicate]

I have a function $\phi(t)$ and I want to define a function $\phi D(t,r):=\phi^{(r)}(t)$, in other words evaluate the $r$'th derivative of $\phi$ at $t$. The naive code that I have is: ...
1
vote
1answer
103 views

Sort lists of vertices {indegrees, outdegrees} by indegree

in = VertexInDegree[F]; out = VertexOutDegree[F]; I want both in and out to be ordered by in. Example: graph has nodes a,b,c with indegrees 1,2,0 and outdegrees ...
1
vote
1answer
57 views

Replicability of RandomVariate within a function?

I have a rather basic question but can't figure out a foolproof answer. In the following code, I build a function which returns the mean difference between successive elements of a vector created from ...
0
votes
0answers
34 views

Table of values for functions with random variables [duplicate]

I'm trying to get a table of values for functions with random variables. First of all, i have a function like that: ...
0
votes
0answers
153 views

Financial Derivative european call option

When estimating financial derivatives like a european call option there is a parameter named: dividend paid per time unit. What does this mean, I have not been able to find any more information about ...
0
votes
1answer
88 views

Problems with For statement

I'm trying to iterate some expression through for loop: ...
0
votes
1answer
252 views

Mapping a function over n levels

I want to map a function over a matrix of rank n, for example: ...
11
votes
4answers
992 views

Plot the minimum of a list of functions

This is my first question on any stack-exchange site and I'm also very new to using Mathematica software so please excuse/correct me if I mess up. I would like to take a list of functions of a single ...
2
votes
3answers
842 views

Testing for continuity over a given domain

Is there any way to use Mathematica to test whether a function is continuous over a given domain?
1
vote
1answer
88 views

Compose two special power series expansions

I have two functions $A(x), B(x)$, given in a special power series form: $A(x)=1-x^{2}\left(\frac{a}{10}-\sum_{k=1}^{9}b_{k}\left(\frac{(x^{2}-1)}{r}\right)^{k}\right)$ ...
2
votes
0answers
124 views

A math function similar to “LatticeReduce” for finding linear independent basis

We would like to ask a math function similar to "LatticeReduce" for finding linear independent basis. The input is a list of vectors $M=\{v_1,v_2,v_3,\dots\}$, with the following property: There is a ...
4
votes
4answers
309 views

Speed up replace all

I have large list of rules, I would like to use list/.rule, but assume that rule is a set of rules rule 1, rule2 rule...I want ...
2
votes
1answer
202 views

Plotting attributes of vertices in WattsStrogatzGraphDistribution[n, p, k]

I have a graph WS = RandomGraph[WattsStrogatzGraphDistribution[n, p, k]]. I need to plot several characteristics of each v: the ...
2
votes
1answer
455 views

Understanding the difference between matrix indices and image coordinates in context of ListDensityPlot

In Mathematica help it's written that: ListDensityPlot[array] -> generates a smooth density plot from an array of values. ...
6
votes
1answer
137 views

Is it possible to circumvent a bug inside SeriesCoefficient?

As far as I can tell, there seems to be a bug in SeriesCoefficient: ...
2
votes
1answer
571 views

Matrix exponential MatrixExp[] vs Sum[MatrixPower[]] doesn't match?

I might be an idiot, but I cannot get the manual expansion of $e^{At}$ to match the MatrixExp[A t] result. For example, I have the following: ...
0
votes
3answers
97 views

Half kth term if n is even and k=n/2?

I am trying to write a function which will perform the equation in the attached image. So far, I have: ...
2
votes
1answer
380 views

How to define a list that contains all primes less than x?

how can I define my own list in which I have all primes less than x?
2
votes
1answer
195 views

Discontinue, then continue x-axis of 2D Histogram

I have the pictured Histogram. It was generated by the following lines: ...
0
votes
2answers
1k views

How to find number of connected components of graph G?

Is there a command that can count the number of components of a graph, in the same way that VertexCount[G] counts vertices?
1
vote
1answer
236 views

How to study the sign of an expression including a function, with conditions on the function?

I'm trying to study the sign of an expression, having information on some of my parameters. I don't know how to code these conditions. For example, I want to know when this expression: ...
0
votes
0answers
19 views

Using functions as input for a function - won't simplify [duplicate]

I've defined a function P[k_] := 1/[Sqrt]2 (R[k] + L[k]) where R and L generate matrices. However the output of this function never full simplifies (even when I use the Simplify[%] functions). It ...
2
votes
0answers
1k views

Derivative of the Absolute Value Function in Mathematica looks very different from the actual answer

Derivative of the Abs Function in Mathematica looks very different than the actual answer. Why? How to correct this? For example I entered ...
2
votes
1answer
150 views

A question about definite integrals and timing

I need to integrate the expression G given below: ...
1
vote
1answer
88 views

FlipView Alignment problem

Here's the problem with MWE: Framed[ FlipView[Framed /@ {100, 1}, Alignment -> Center] , ImageSize -> {100, 150}, Alignment -> Center] I ...
2
votes
0answers
73 views

Complicated output from simple Eigenvalues problem

I have code that uses Eigenvalues on matrices of various sizes. But the output of what should be a very simple problem, namely finding the eigenvalue of a 1x1 matrix, is overly complicated. ...
0
votes
1answer
99 views

Blank plot that shows up briefly when changing plot options

I wrote some code in Mathematica to calculate and plot, in tw0 different ways, a function depending of two variables. But the plots are empty even if it takes a few minutes to evaluate the plot ...
5
votes
2answers
466 views

Manipulating slots in a pure function

How does one manipulate the slot numbers in a pure function? Some trick with Evaluate or Hold? I'm aiming for something along ...
0
votes
0answers
43 views

Verify “Type” of solution [duplicate]

I've written some Mathematica functions which allow the user to verify if a mathematical function has certain properties. What I'm basically doing is generating "random" functions in respect of ...
3
votes
2answers
517 views

How to copy a function by value?

I need to change a function symbol multiple times by assigning another symbol to it, but when I'm trying to do that the symbols overwrite each other. I'm assuming this is because the assignment is by ...
0
votes
1answer
94 views

nested series expansion

I have to invert the following matrix in which the functions U[t,x,y,r] and K[t,x,y,r] and all their derivatives are "small"; ...
1
vote
0answers
27 views

Minimizing roots of a transcendental equations [duplicate]

I'm trying to use the solution of FindRoot with parameters for further calculations. Annoyingly enough it always gives me trouble with replacing the parameters. As an example I'm attaching a simple ...
1
vote
1answer
87 views

Selection of the position of the variable

I defined a function funloglogplot to make a loglogplot of a function (function1) depending on several variables ...
0
votes
1answer
79 views

How can I represent this automorphism of Q(i,a)?

Let $a$ represent some real irrational number. I am trying to perform computations with an automorphism $f:\mathbb{Q}(i,a)\to\mathbb{Q}(i,a)$ which fixes $\mathbb{Q}(i)$ pointwise and maps $a$ to $i ...
0
votes
0answers
57 views

Fold Dynamic Function [duplicate]

I'm making on a demo working with differential equations as functions of two variables (x and y). The demo will have to Fold the differential equation with an initial y-value and a series of x-values. ...
0
votes
1answer
136 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
31
votes
2answers
2k views

Scan vs. Map vs. Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
3
votes
2answers
529 views

Need to create a function to generate all permutations of Range[$n$] [duplicate]

Basically I need a function that takes a list and gives all the possible permutations of it. The reason I can't use Permutations is that I have to apply another ...
2
votes
1answer
115 views

What is happening in Map[Function[x, x^2], a + b + c] from the Pure Function tutorial

The Pure Function tutorial gives an example: Map[Function[x, x^2], a + b + c]. I would expect the output to be (a + b + c)^2, ...
6
votes
2answers
567 views

Understanding Transpose

It is very likely that it is my lack of math skills that is showing up here. However, I think Transpose is such an important function that I need to master it. So I ...
2
votes
1answer
294 views

Dynamically Updating Function

I use Mathematica 8 and am working with DynamicModule. I'm trying to enter a function in an InputField then later apply it to two values entered in subsequent Input Fields. The function just does not ...
3
votes
0answers
71 views

Can BreadthFirstScan be modified?

I would like to obtain a "slick" implementation of A*-search algorithm on Graph objects, using the built-in BreadthFirstScan (if that is possible at all). I noticed that BreadthFirstScan is static in ...
8
votes
3answers
541 views

How to protect functions in a Mathematica Package?

I'm writing a Mathematica Package with many functions, but only two can be seen/public. I have: ...
1
vote
1answer
317 views

Is there a function for falling factorial in Mathematica

If I had to construct a function for falling factorial in mathematica I'd do something like that (hope I'm not mistaken): fallfact[x_,k_]:=$\prod_{j=0}^{k-1}(x-j)$ But is there a built-in ...