-1
votes
0answers
44 views

Problem with distinguishing terms in a sum

I am doing a sum and the code for this is given as ...
0
votes
2answers
38 views

Notebook cells space on disk profiler

I have one single notebook with more than 500 mb... To control its growth, I would like to have a profiler of used space (not the live memory, but the space on disk), in such a way that I can easily ...
4
votes
2answers
88 views

Simplifying expression with non-commutating entries

Say I have an expression such as (a + X)**(b-Y) where the variables above possess the following commutation relations [a, b] = [a, X] = [a, Y] = [b, X] = [b, Y] ...
3
votes
0answers
47 views

Why does FreeQ seem not to work with complex numbers?

I guess I do not understand how Mathematica evaluates this simple expression inside FreeQ ...
5
votes
1answer
70 views
7
votes
3answers
228 views

Copy/Pasting a Grid of Numbers from Project Euler

On Project Euler Problem 11 (link: https://projecteuler.net/problem=11), there is a 20x20 grid of numbers. However, when I pasted it into Mathematica, I got this strange result where the times symbol ...
3
votes
3answers
154 views

Matrix with known entries but unknown size [on hold]

I am trying to perform some calculations with a matrix that has let's say size N but unknown, please How can I write this in mathematica?
3
votes
1answer
25 views

How can I get the vertex labels of an existing graph?

For example, if there is a graph g = CompleteGraph[5, VertexLabels -> {1 -> "v1", 2 -> "v2", 3 -> "v3", 4 -> "v4", 5 -> "v5"}] How can I later ...
5
votes
2answers
93 views

Can the increment in Manipulate, Table, Range, etc. be subject to an If statement?

In this demonstration I'm working on, I would like to plot a piecewise function with the tangent line to the function at a point that is determined by c in the code ...
3
votes
1answer
77 views

Where can I access documentation for old versions of Mathematica?

Some documentation of functions available in old versions of Mathematica (and old packages) is available online, e.g. http://reference.wolfram.com/language/Combinatorica/ref/Vertices.html Is there ...
3
votes
3answers
128 views

Calculating $\lim_{x\to 1} \, \int -\frac{i \text{Li}_2\left(x-x^2\right)}{\sqrt{3} \left(x-\frac{1}{2}-\frac{i \sqrt{3}}{2}\right)} \, dx$

How can we force Mathematica to compute this limit? $$\lim_{x\to 1} \, \int -\frac{i \text{Li}_2\left(x-x^2\right)}{\sqrt{3} \left(x-\frac{1}{2}-\frac{i \sqrt{3}}{2}\right)} \, dx$$ It seems it ...
0
votes
0answers
47 views

Is there any way to perform an ANOVA test given $n$, $\bar{x}$ and $S^2$?

Suppose I have the following data about the incomes of residents of three cities. $$ \begin{array}{|l|c|c|c|} \hline & n & \bar{x} & S^2 \\ \hline \text{City A} & 10 & 2.8 & ...
2
votes
0answers
73 views

Converting integral equations to differential equations

I am trying to use Mathematica to convert integrals to differential equations, of any order. An example of an integral equation is given below, in Mathematica code. Could you please advise as to the ...
2
votes
2answers
92 views

How to remove multiplicities from for a list in way meeting special criteria

I have a list of pairs, tabul, which has the property that the second element of each pair is also an element in my list data. I ...
14
votes
1answer
836 views

my Mathematica has turned orange and not able to find out why

I do not know what happened. But when I rebooted my PC, now Mathematica comes up orange colored. I shut down the PC and tried again, it is still orange. Here is screen shot: I also did a reset. ...
2
votes
2answers
103 views

Plotting a set of points given by a complex expression [on hold]

A have the set consisting of the complex numbers $1+3r \cosθ−ir \sinθ$, where $r∈[0,1]$ and $θ$ may vary between $0$ and $2π$. This is my first encounter with Mathematica, and am having difficulty ...
0
votes
0answers
28 views

Finding the diagonal matrix of coefficients for a nonlinear set of equations [on hold]

Suppose we have $ \widetilde{k_1} $ and $\widetilde{k_2} $ in term of $k_1$ and $k_2$. We want to find a matrix that relates this variables to each other. Here is the relations. $$ \widetilde{k_1} ...
0
votes
0answers
44 views

How to use NDSolve to solve the system of differential equations? [on hold]

Reference: Mathematical model for HIV/AIDS with complacency in a population with declining prevalence from http://downloads.hindawi.com/journals/cmmm/2006/471467.pdf I found the differential ...
0
votes
1answer
27 views

Compute complete graph and make minimum spanning tree

I'd like to plot a complete Graph and then compute the Minimum spanning tree of it. I already can make a complete graph out of a list that countrydata gives me: ...
5
votes
2answers
108 views

How to export images in EPS format that can be opened in CorelDraw

I am preparing a paper. The journal requirements are odd: only eps files for pictures are accepted. All pictures I have drawn in Mathematica and exported in eps format in the usual way: ...
0
votes
0answers
43 views

Comments including LaTeX commands in Mathematica [duplicate]

I want to write some comments in Mathematica - which include LaTeX commands - using the form ...
4
votes
1answer
104 views

How to check the option value?

Given that I have a function func as follow: To check the value of options, I using the step-by-step method If[] ...
7
votes
4answers
187 views

How to Apply Functions to Lists with Many Curly Brackets?

For example, consider the list defined below. samplelist = {{{1,2,3,4}}, {{5,6,7,8}}}; How would I apply the Times operator ...
0
votes
0answers
27 views

FoldList[Union,…] version 8 vs version 9 [duplicate]

I have a list of matrices something like shown below A = {{{1,1,1,1,1},{2,2,2,2,2}},{{3,3,3,3,3},{4,4,4,4,4},{5,5,5,5,5}}} When I try to run the code ...
0
votes
0answers
164 views

Why does my calculation of a probability take too much time?

I am calculating the value of the following function for given argument values: ...
0
votes
1answer
50 views

Functions becoming undefined when evaluated

I'm so confused I don't even know how to phrase my Question title. My function nextCol works until I use colLength, then ...
3
votes
2answers
47 views

Faster use of Condition for a large array (see the example)

Here is the example/problem. I have a array of $n$ random number. n = 2000; p = RandomReal[{0, 9}, n]; I have to create a $n\times n$ sparse matrix with ...
0
votes
0answers
45 views

Solving a system of nonlinear equtions [on hold]

I'm trying to solve a system of nonlinear equations which consists of 12 variables and 12 equations. A solution is obtained, but with an error. FindRoot::lstol: The line search decreased the step ...
0
votes
0answers
36 views

Why doesn't Mathematica support Import for SWF files? [on hold]

Why doesn't Mathematica support Import for SWF files? I saw that Mathematica can export to .swf, but I wonder why it does not import .swf files?
-1
votes
0answers
45 views

Building Pythonic Programming style to Mathematica with visually-accessible list comprehensions?

The question List comprehension in Mathematica has comment about this Functional style using lazy lists? where they build some sort of style for lazy lists: I understand it so that it is impossible to ...
4
votes
3answers
83 views
4
votes
2answers
49 views

Building up a sequence dealing with a complex recursive scheme

Suppose I have multiple lists, the first one contains 2 elements, the next one 4 elements, the next one 8 elements, and so forth. Let these elements be labeled as Gij where i refers to the list it ...
0
votes
0answers
30 views

Optimization over 6 vectors

Suppose I have an expression which depends on 6 unit vectors (3 dimensional). Hence, I need to optimize over 12 parameters (every vector contains 3 parameters, but one we can reduce by considering ...
3
votes
1answer
78 views

How to tell Mathematica that my variable is a scalar

In my calculations I have these combinations PauliMatrix[1].f PauliMatrix[2] where f is a scalar function. The result is as ...
3
votes
1answer
65 views

How to get the size of a specific image in the front end?

The title pretty much says it all. One possible point of confusion is that this question is not limited to items with head Image. I don't know what is the ...
4
votes
2answers
72 views

How to scale multiple graphics to preserve relative sizes?

I'm looking for a simple way to make the displays of different Graphics expressions accurately reflect their relative sizes. (By "simple" I mean that it does not ...
5
votes
3answers
74 views

Conditional subset generation

I am trying to accomplish the following task: Given a list of coordinates of n points in the plane, I need to find subsets of all points that share the same ...
4
votes
3answers
198 views

Drawing a ladder graph with Line and Table/Array

I want to programmatically draw a ladder graph like the one below: I'd like to use Table to dynamically add steps. My (lame) attempt so far: ...
1
vote
1answer
77 views

Labeling a ListPointPlot3D

I've a problem with the label of ListPointPlot3D. I tried to reproduce a plot I've seen in a paper, but I was not able to reproduce it completely. Following and example of my data: ...
1
vote
2answers
75 views

Non Linear Model Fit (Division by Zero Error Message)

Can someone please tell me why this expression returns error messages about division by zero. ...
0
votes
0answers
30 views

Numerical minimization hangs at some steps

Let me briefly explain what I observe and cannot really explain by myself. I occasionally use NMinimize to find optimal parameter sets and sometimes it happens that ...
3
votes
2answers
143 views

Von Kármán Vortices

How may we vary vectors in StreamPlot[{y, -Sin[x/2]}, {x, -4, 12}, {y, -4, 4}, StreamColorFunction -> "Rainbow", AspectRatio -> Automatic] to obtain a ...
13
votes
1answer
131 views

How to retrieve current FaceForm?

The current colour in a Graphics object can be retrieved using CurrentValue["Color"] for use in Dynamic stuff. Example: ...
0
votes
1answer
45 views

Saving numerical values to a *.dat file

I have a function like this: ...
2
votes
1answer
52 views

The Summation of a Summation in Mathematica

I am trying to input $\sum_{a_1=1}^{n-1}$$\sum_{a_2=1}^{{a_1}-1}$$\sum_{a_3=1}^{{a_2}-1}$$\sum_{a_4=1}^{{a_3}-1}$$...f({{a_1},{a_2},{a_3},{a_4}...})$ into Mathematica. The number of sums should be a ...
3
votes
2answers
62 views

Iterative Tree Plot for the Sum of an Integer's Digits Squared

I am trying to make a graph that depicts integers<100 mapping to the sum of their digits squared. I can do this for one iteration, but I don't know how to do it for more than one, or until the new ...
1
vote
1answer
38 views

Remove line breaks or return codes from string

I have imported string data, which appears to have line breaks or return codes in it invisible in a notebook input cell. Copying a string and pasting into Apple Pages with control codes showing gets ...
5
votes
0answers
77 views

Compiling FoldList implementation for RK4

Original I'm looking to write an integrator for a function of two variables. Here is my implementation for the RK4 update rule using FoldList. ...
3
votes
1answer
53 views

Iteration variable in variable [duplicate]

Is it possible to create following list by some sort of iteration? {a1,a2,a3,...,a100} I cannot think of any way to append a to ...
0
votes
0answers
58 views

NDSolve Syntax Error- 29 simultaneous differential equations [closed]

Please note that I do not need a detailed solution specific to the equations, but rather a general way to fix the error. I am trying to solve 29 simultaneous differential equations in Mathematica ...

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