# Tagged Questions

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

182 views

### Laplacian in D Dimensions

Is it possible to compute $\Delta F=\nabla^2 F$ for $F=F(x^1,x^2,…,x^D)$ with $D$ finite? I seem to be only able to specify spherical coorindates, for example, if I want to leave standard ...
170 views

### Cannot solve equation

I just started using mathematica and I'm facing a problem that I just can't solve. I want to solve the following equation: Code: ...
110 views

### How can I define a function that takes a list of reals?

I'm trying to define a function f which takes a list of reals. My purpose is to build a function which I can give a list of reals, integers or strings and have it ...
311 views

### Defining a function as a sum of several Gaussians

I have a function that is a summation of several Gaussians. Working with a 1D Gaussian here, there are 3 variables for each Gaussian: A, ...
666 views

### Tracking iterations of a function

I'm learning MMA with Wagner's book. On page 41, he uses this to display the iterative steps of a FindRoot. However, I can't seem to replicate this (code at end), perhaps due to the difference in MMA ...
108 views

### Function pattern to support listed and non-listed arguments [duplicate]

I often want to write functions that take as an argument either a) a rule or b) a list of rules. As an example, when using Replace with just one rule, it does not ...
312 views

### What is wrong about Abs[x]-a? Is it a bug?

Why is the Out[74] not {1 - a, {x -> -1}}? ...
99 views

### Create polynomials from Series

This question actually doesn't have quite a lot to do with the Series function, but I don't know how to describe my problem. So here's the thing. I'm trying to ...
371 views

### Define function that counts recursive fibonacci

If I write count=0; fib[0]:=(count=count+1; 0); fib[1]:=(count=count+1; 1); fib[n_] := (count = count+1; fib[n-2] + fib[n-1]); Then I can ...
2k views

### How to completely delete the head of a function expression

Is there any way to completely remove the head of an expression function? For example, how would I remove the head Cos from ...
171 views

### Expression for evaluating multiple functions?

I am constructing 3D data points for a plot and corresponding to specific conditions "manually". I define the values of five parameters [these I always have to define myself]. From those, I evaluate ...
325 views

### Counting number of inversions

Is there an inbuilt method to find the number of inversions in a set of numbers? I found Inversions in Combinatorica but when I ...
90 views

...
87 views

### Switching the ordinate and abscissa causes problem in ParametricPlot

I have a function that plots properly in PolarPlot, but I'd like to plot it in ParametricPlot and then switch the y and x values,...
197 views

### Is there a way to make the MemberQ function apply to a list?

Is there any way to ask a boolean question if the elements of the list {2,5} are in the list {1,2,3,4,5}?
77 views

### How I can define a new function as a function argument?

I need to pass a function with t as independent variable as a function parameter and want to create a new function of the same through this provided the argument of another function. Here is my code. ...
257 views

### Getting “Null” output from package?

I have a script written to test a package as follows: ...
3k views

### How to pass a list as function argument?

I have the following function lFreqPhylo[a_, Q_, b_, p_] := Sum[Log[freqFunction[r[[p]][[i]], L[[p]][[i]], a, Q, b, {i, 1, nbranches[[p]]}]; The objects L, r ...
142 views

### Creating Do loop that cycles back to earlier values

I need to create a Do loop that distributes letters in a list of lists. I also need to be able to cycle back through to the beginning of the list. For example, I ...
131 views

### ToExpression and Fortran notation

ToExpression["9.0E-03"] interprets the string as 9*e - 3 instead of what I am expecting: ...
102 views

### Apply function to output of previous function

I am trying to write a function that takes 3 tuples. Each tuple contains two lists which are first divided. This results in 3 lists. Then I want to take the Mean of all the columns. I can do this ...
127 views

### Vertex hides point where edges cross - how to move vertex?

I have this graph: ...
161 views

### Inverse functions - how are they calculated?

Mathematica is able to calculate InverseFunction[LogIntegral] and InverseFunction[RiemannR] (and many other inverse functions). ...
177 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 : \label{}(1) \left\{ \...
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 ...
78 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 ...
143 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] ...
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 ...
674 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 ...
194 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: ...
105 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 0,...
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 ...
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: ...
157 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 ...
89 views

### Problems with For statement

I'm trying to iterate some expression through for loop: ...
255 views

### Mapping a function over n levels

I want to map a function over a matrix of rank n, for example: ...
1k 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 ...
867 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?
89 views

98 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: ...
390 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?
197 views

### Discontinue, then continue x-axis of 2D Histogram

I have the pictured Histogram. It was generated by the following lines: ...