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

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4
votes
1answer
143 views

What is the relationship between Thread and MapThread

I hope this is not a silly question, since there are plenty of questions on Thread and MapThread. However, I still cannot quite ...
1
vote
1answer
75 views

How to find the domain of an arbitrary function?

I got stuck here: fuu[x]:= 1/x +2x^2 Reduce[Exists[{x},fuu[x]],Reals] of course it doesn't work like this. How can i check if there will be divided by zero or if ...
0
votes
0answers
42 views

Constructing a function for expanding general $n$ products

I have the following quantum mechanically motivated product: $\langle0\vert(A_1b_1 + A_2b_2 + A_3b_3)(B_1b_1 + B_2b_2 + B_3b_3)(C_1b_1 + C_2b_2 + C_3b_3)$, where $b_i$ is an annihilation operator ...
5
votes
1answer
74 views

Shadowing of optional function arguments?

I am trying to define two different packages that process some information in a different way. These packages have functions into them with optional arguments. The names of the optional arguments ...
1
vote
1answer
67 views

Transposing X and Y on a plot [duplicate]

This question has appeared in many forms online, but none directly apply to my problem. I have a quite complicated, albeit bijective function of the form ...
2
votes
0answers
44 views

Computing an inexact derivative with some terms preserved in exact form

I am beginning to learn Mathematica and have the following question: How can I return a derivative with exact numbers instead of one involving numerical approximations? My original, single variable ...
2
votes
1answer
195 views

Making Mathematica function files like in MATLAB

I'm a MATLAB user trying to get familiar with Mathematica. I have long Mathematica sheet that spits out some matrices at the end after much math. I want to run a loop over couple of different initial ...
3
votes
2answers
69 views

understanding a mathematica equation

I have found the equation below written with Mathematica, I looked at the Mathematica online guide but it is still difficult to understand the equation. Can someone write this (or part of it) in ...
4
votes
3answers
388 views
5
votes
3answers
116 views

Encapsulated plot function misbehaves

To insure a collection of plots has identical appearance, the plot command is encapsulated in a function. The results are undesirable. The fiducial plot is ...
2
votes
1answer
99 views

Missing zero in the CoefficientList

The following list has a length only 10 (not 11) CoefficientList[Series[ArcTan[x]/(1-x^2),{x,0,10}],x] {0, 1, 0, 2/3, 0, 13/15, 0, 76/105, 0, 263/315} It should ...
3
votes
5answers
182 views

Converting multi variable expression into a function

So I have this rather complicated looking expression ...
0
votes
0answers
59 views

Which method to use for finding maximum without actually computing optimization function explicitly?

I am new to Mathematica and I am currently working on an optimization problem. The optimization function that I have easy to calculate for some assignment of variable but it is very difficult to ...
3
votes
1answer
177 views

I want to construct a function than the output is “Sequence”

For example if the input is x and x<10 the output is Sequence[x,0],if x>10 the output is Sequence[0,x] but obviously ...
2
votes
1answer
94 views

How can I run a summation numerous times?

I have been working on code for finding the Allan plot of generated white noise, however, I cannot figure out a way to automate it for a different range of numbers. My code is as follows: ...
2
votes
0answers
46 views

Marginal distribution with weight

Given a multi-variate distribution $P(\mathbf{x},\mathbf{y})$, I would like to obtain the marginal distribution $$P_m(\mathbf{x})=\sum\int_{\mathbf{y}}P(\mathbf{x},\mathbf{y})W(\mathbf{y})$$ In my ...
18
votes
1answer
399 views

What are SparseArray Properties? How and when should they be used?

A strange undocumented form of SparseArray is increasingly used in answers on this site: ...
0
votes
0answers
93 views

Polynomial interpolation using Neville's Algorithm

Is there an interpolating function in Mathematica which uses Neville's algorithm? I have written a C++ program to do interpolation using Neville's algorithm and I am getting a small difference ...
4
votes
1answer
92 views

How to create fast functions based on units?

Using units is a good means for rapidly developing code, since it provides some error control. Hovewer, using Mathamatica functions containing units appears to be copmutationally inefficient. ...
15
votes
0answers
230 views

Is FullGraphics an abandoned function? Is there an alternative?

FullGraphics hasn't worked entirely for a long time and the situation appears to be getting worse instead of better. In Mathematica 10.0 and 10.1 a simple usage ...
0
votes
0answers
36 views

Attributes of statistics functions

Do statistics functions have some kind of attribute which ignore non-number (Indeterminate, ComplexInfinity, calculation "errors") elements of a list?
2
votes
1answer
71 views

Computing large nested values

Is it possible to compute a value for n=10^9; Nest[# + Log[#] &, 2., n] for large n? $10^9$ seems to be the max for me - ...
0
votes
3answers
110 views

beginner's question: change a parameter while get variable answers [duplicate]

I'm new to Mathematica from R, since R is not quite good at dealing with the following problem. Say, i want to solve the function a x - 10 = 0. Each time I change the value of a, say, from 1 to 10 by ...
0
votes
2answers
84 views

Continuity of function-example

I'd like to examine the continuity of the following function: f[x_] := Limit[(n^x - n^(-x) ) / (n^x + n^(-x) ), n -> Infinity] I know that this function isn't ...
18
votes
0answers
309 views

Performance problems in new Sequence functions

The new-in-10.1 Sequence* family of functions should provide newly optimized methods for handling sequence problems. Happily in some cases they do! For example ...
5
votes
1answer
92 views

Handy dates conversion

I feel like something very basic is missing me, $dateformat = {"Year", "Month", "Day", "Hour"}; date = DateString[$dateformat] DateString["Date"] ...
18
votes
1answer
301 views

In 10.1.0 BenchmarkPlot doesn't work?

Bug introduced in 10.1 and fixed in 10.2.0 In Mathematica 10.1.0 BenchmarkPlot from the GeneralUtilities package doesn't work; copying Taliesin Beynon's initial ...
1
vote
1answer
83 views

How to construct a kernel from a function?

I would like to convolve an image with a mathematical function. I understand that I need to have the mathematical function in a matrix form. How can I build it? Thanks
2
votes
2answers
107 views

Creating a Cayley's table of square

I'm interested in creating a Cayley's table of square using Mathematica. I'm not a programmer but occasionally resort to using Mathematica to simplify my work insofar as the programming doesn't take ...
1
vote
1answer
104 views

Understanding `FixedPoint`

I understand that FixedPoint[(# + 2/# )/2 &, 1.] can be written ...
0
votes
0answers
26 views

Fibonacci series up to 300 terms [duplicate]

I tried to generate a list of Fibonacci numbers up to 300 terms and gets a runtime error. f[0]=0; f[1]=1; f[x_]:=f[x-1]+f[x-2]; Table[f[x],{x,1,300}] Is there ...
19
votes
2answers
234 views
2
votes
2answers
124 views

Input a non-string input — output as a string

I am trying to create a function that needs to transform its input into a string. The objective is to transform a $\LaTeX$ mathematical expression into an executable Mathematica expression. ...
0
votes
1answer
52 views

Question about a catalytic equality?

I have a question on math.SE that explains how I came up with these equations. ...
3
votes
3answers
148 views

truncated square wave input

I'm investigating the response of some dynamic system on Mathematica and I want to generate a tailored square input like the one in the following picture: Does anyone know how to generate such input ...
-2
votes
3answers
65 views

Two unrelated questions: 1. Output of Series[] for function, 2. Output conditional answers as if not conditional [closed]

As mentioned in the title, I have two questions. 1. I have code that looks similar to: ...
1
vote
2answers
80 views

How to stop FullSimplify from returning Root objects

I have several expressions in a series, such as 1/4 (-(1/4) + Sqrt[5]/4 + I Sqrt[5/8 + Sqrt[5]/8]) (-1 - Sqrt[5] + 2 Sqrt[7/2 + (5 Sqrt[5])/2]) If I run ...
-3
votes
2answers
89 views

Random Polynom Plot [closed]

I should write a module "RandomPolyPlot[n, amin, amax]" which calculates all roots (nulls) of a n-th degree polynomial function. Then I should illustrate it on the complex plane. I also should ...
3
votes
1answer
78 views

Why minimization does not work with symbolic array as arguments

If I try to minimize with constraints a function of several variables, with Gamma regularized function involved in the constraints it seems to works, as shown below (this is just a dummy example ...
1
vote
2answers
94 views

Get the sum with cases

I have the following list: list = {{1, 2}, {2}, {3, 4, 1}, {5, 4}, {3, 3}, {a, b, c}, {e, f}, {g}, {}, {Sin[a], Cos[b]}}; I should use ...
-3
votes
2answers
92 views

Write a function, write a pattern [closed]

I have the following list: list = {{1, 2, 4}, 6, 7, 8, {8, 2}, {3, 4}, {4, 5}, {1, 2, 3, 1}}; (a) I should write a predicate-function in combination with an ...
0
votes
0answers
28 views

Why don't we use SetDelayed when we use placeholder to declare a function? [duplicate]

On the answer of http://stackoverflow.com/questions/4272067/what-does-mean-in-mathematica Typically when we declare f(x)=x^2 function, it is: f[x_] := x^2 But ...
0
votes
0answers
40 views

How can I put the results of TrigReduce function into a more convenient form? [duplicate]

a1 D11 Cos[n x] + a0 a1 D11 Cos[n x] + 1/2 a1 a3 D11 Cos[n x] + 1/2 a2 a4 D11 Cos[n x] .......for example this expression can be written like ('expression') * ...
2
votes
1answer
117 views

How to run code in a saved file when it is opened

I have a Mathematica file that I saved. In it, I have multiple functions that I've defined and have evaluated a number of the functions with different arguments. I would like to be able to open the ...
1
vote
1answer
68 views

Defining a Function

I've been reading about functions in Mathematica and playing with this for hours, but I'm clearly missing something. The following code correctly calculates "fail", the number of failed scenarios. I ...
1
vote
1answer
211 views

Create a function with Dt[x] as a variable

I have a function (for example F[x_]:=Cos[x]). I want to define a function like Fdot[x_,xdot_]:=Dt[F[x]] where xdot represents Dt[x]. For example, to define Fdot one might naivley try ...
1
vote
0answers
32 views

Import names into notebook namespace

I have function that at some point has list of strings (e.g. {"apple","pear"}) and I want to declare (initialize) those variables in notebook namespace to default value (e.g. 0) so I could execute in ...
0
votes
1answer
125 views

How can I use nonlinear model fit with multiple variables? [closed]

I have a data set with four entries. the first three entries correspond to variables in the fit x,y, & z. The fourth entry corresponds to the function value. I am trying to fit this data to a rate ...
2
votes
1answer
129 views

How do I download and export data from many weather stations?

I tried this code, which downloads data from several weather stations. ...
0
votes
1answer
72 views

How to properly use conditionals inside NDSolve

Currently I am working with Mathematica to learn the program, and I'm confused what exactly is wrong with this code. ...