1
vote
1answer
180 views

Importing adjacency matrix from file of 0/1 arrays

Is it possible to import adjacency matrix for graph representation, from simple text file with NxN (rows x columns) of 0s/1s: 0 1 0 0 1 0 1 1 0 1 0 0 0 1 0 0
0
votes
1answer
107 views

Generalizing Characters to n-character substrings [duplicate]

I'm doing some frequency analysis on an encrypted plaintext. Tally[] and Characters[] make the basic task quite easy. To count the number of times each character appears (sorted alphabetically; ...
2
votes
1answer
227 views

What is wrong with setting one list to another within function? [duplicate]

I have built a function which carries out a set of operations given two parameters. The function looks as follows: ...
5
votes
1answer
114 views

Is it possible to Print into a collapsable CellGroup?

During rather long computation I have intermediate steps Printed with useful information which should be collected for possible use in future inside of the ...
7
votes
1answer
150 views

Converting string representation of boxes into explicit boxes [duplicate]

It is very easy and convenient to write textual labels as Strings in the WYSIWYG mode. For example, I define a short form describing a linear model: ...
3
votes
1answer
340 views

Are there any more time-efficient ways to solve a matrix equation than with SparseArray and LinearSolve?

I am trying to solve a matrix equation, with the matrix being tridiagonal. The problem I am having is that a message keeps appearing that I don't have enough memory. Here is the code: ...
2
votes
1answer
507 views

Prove (or check) an expression is positive given constraints on variables?

I'm trying to figure out whether an expression is always positive given positive parameters. When the expression is complicated, I can't do this by eye. Is there any way to make Mathematica prove ...
7
votes
2answers
578 views

Combining three R, G, B matrices into a single matrix of 3-tuples?

Working with Mathematica 8 on OSX here. I have three $1024 \times 1024$ matrices representing the counts from consecutive exposures onto a CCD with $R$, $G$, and $B$ filters on it, and am looking to ...
3
votes
2answers
946 views

Symbolically solve a system of coupled second order differential equations

I have posted a similar question in another forum where the general consensus seems to suggest that it is not possible to symbolic solve a system of coupled second order differential equations with ...
2
votes
2answers
1k views

How to make lines in Plot Legends wider?

1.- How to put DASHED lines in the Legend? 2.- How to give Style to {20,Bold} to all "Expressions in Legend? (I use LegendMarkSize for make lines wider than default fine style ) ...
1
vote
1answer
1k views

How to find non zero elements of a list containing zeros and symbols

I have a list, obtained after differentiating a list of expressions, which contains zeros and symbols, say: A = {x1^2, x2^2, x3^2, x4^2} D[A,x3] results in the ...
0
votes
3answers
113 views

How to get the indices of values in a list which are NOT an specific integer?

I got a real array A, where Dimensions[A] == {5000, 5000, 5}. Some of the values in A are ...
12
votes
3answers
357 views

Taking Top K Occurrences

Having millions of numbers in a list, I want to take top K occurrences. MMA Commonest is very slow so I write my own versions: ...
11
votes
3answers
771 views

Labeling plots without evaluation

This is my first question here so please excuse my mistakes. Let us consider a rather contrived example: ...
1
vote
4answers
158 views

How to count number of {True,True} outputs?

Do[Print[{x + y + z == 3, x + y > z}], {x, 1, 2, 1}, {y, 1, 2, 1}, {z, 1, 2, 1}] If I run this syntax I get a series of Outputs, I am trying to Count only the ...
3
votes
0answers
378 views

Travel time sweet spot using: Mathematica and Google Maps API

I want to use Mathematica to do some time minimisation calculations calling on Google Maps API for travel time data. I'm concerned with travel time, e.g. along roads (by car or walk) and not linear ...
3
votes
1answer
213 views

Zooming into animated plot

Let's say I have the following animation: Animate[ParametricPlot[{Cos[a t], Sin[a t]}, {t, 0, 1}], {a, 0, 2Pi}, AnimationRate -> 0.1] Is there a way to ...
3
votes
2answers
2k views

How does one specify Neumann conditions for NDSolve?

I have a series of functions defined in my notebook, and then want to use this to solve a diffusion-reaction type equation. At the moment, something like this works: ...
6
votes
1answer
433 views

How to change a parameter dynamically inside NDSolve

I have no idea how to dynamically update a parameter inside NDSolve. For example consider following first-order DE: ...
5
votes
1answer
444 views

windrose with data from Excel

How to Import data from excel and use them to Plot windrose instead? Example, {{Strength, Angle(degrees)}..} ...
5
votes
1answer
208 views

SmoothHistogram with sharp boundary [duplicate]

When using SmoothHistogram (to plot probability distribution function), I noticed that the edge of the figure is automatically smoothed towards zero probability. ...
4
votes
1answer
284 views

Changing Plot order for 3D printing

Alright, I got a my first 3D print done of a pseudosphere using parametric plot and a deflated sphere using a contour plot, but when I try ...
3
votes
3answers
396 views

How to exchange two arguments?

Recently, I have being using Mathematica to write my undergraduate paper. I want to use two pattern lists such as { A -> a, B -> b, c -> C, ....} and ...
5
votes
2answers
646 views

Labeling a grid

I have m = {{0, -1, -2, -3, -4}, {1, 0, -1, -2, -3}, {2, 1, 0, -1, -2}, {3, 2, 1, 0, -1}, {4, 3, 2, 1, 0}}; And a grid ...
0
votes
0answers
55 views

Problem with loading my custom package [duplicate]

I've been having quite a bit of trouble loading a package I wrote. I've followed the suggestions on related questions on this site, as well as on Mathematica's own pages, and still nothing has worked. ...
4
votes
2answers
229 views

How to make sure Table or Do only runs through specific values?

I often need to generate or run through very large numbers of integers (we're talking {i, 1, 10^9} and higher) and want to add certain integers to a list, say ...
0
votes
0answers
29 views

How to put the values/points in a loop into a plot? [duplicate]

I've already make the do loop..it has 200 points..how am i going to put those points into a plot?do i need to make a list@table before doing the plot?here's my loop example, ...
0
votes
0answers
70 views

Polar Plotting in Complex Plane [duplicate]

How would I plot the following functions in the polar complex plane? $$ \phi={-k\over 2\pi r}cos(\theta_0-\theta) $$ and $$ \psi={-k\over 2\pi r}sin(\theta_0-\theta) $$ Please ...
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 ...
6
votes
1answer
187 views

Setting options of expressions similar to using SetOptions on objects

Introduction I often have the problem that in an expression, I want to change an option. If we are sure the option is not present, we could simply use ...
2
votes
2answers
299 views
3
votes
1answer
152 views

How to simulate the 1-D motion of a particle under constant acceleration? [duplicate]

I am trying to represent the position of an object under freefall, but am completely lost. Here is my attempt so far: ...
1
vote
0answers
123 views

Trying to study the three points theorem of the Mobius Transformation

I am trying to study the three points theorem of the Mobius transformation. This theorem says that the Mobius transformation $M$ maps three distinct points p, q, r to three distinct points p', q', r'. ...
1
vote
1answer
84 views

Inaccuracy of Piecewise function? [duplicate]

I have the following issue and can't find a solution so far. ...
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 ...
3
votes
1answer
232 views

Writing results directly to file

I am trying to find all simple paths in a large directed graph (542 vertex, density ~ 5%) between two nodes. For this purpose, I use the algorithm from this thread. Unfortunately, my computer is ...
2
votes
0answers
57 views

Replacing list elements by other list elements [duplicate]

I am a beginner of Mathematica and need some help for the following issue. I have the following two lists: ...
10
votes
1answer
223 views

Importing an mx file into a context

Consider the following simple code which dumps the global context: var = 5; DumpSave["test.mx", "Global`"]; Now, in a new notebook, I would like to import var in ...
2
votes
1answer
146 views

LogPlot and LogLogPlot do not output their legends correctly

When I give lists of functions to LogPlot or LogLogPlot with the option of PlotLegends, ...
11
votes
5answers
2k views

How do you plot the same function with different options over different intervals?

Here is the motivation for my question. I want to plot Sin[x] over the interval 0 to 2 π, ...
1
vote
2answers
215 views

How can I create a list containing the normalized element-by-element product of two given lists?

I have to calculate: How can I create such a sum? Do I have to set the factors of each term manually (one by one), like G1 = 1, H1 = 1, G2 2, H2 = ....? ...
0
votes
1answer
91 views

Trouble fitting an explicitly complex model with the TransformedFit package

This is follow up from a previous question in which @Oleksandr R. suggested the use of a package he developed for splitting a model and data into real and imaginary parts to avoid a problem with ...
1
vote
1answer
393 views

To solve Cylinderical PDE

I want to solve this PDE. I have tried to solve it with NDSolve but found error 'Boundary values may only be specified for one independent variable. Initial ...
4
votes
2answers
206 views

TreePlot, VertexRenderingFunction and stretched vertices issue

Recently I found the following TreePlot issue. For simplicity, I took an example from Mathematica Tree Drawing Tutorial and set ...
6
votes
0answers
499 views

Performance tuning - Explicitly set Mathematica use Nvidia GPU for rendering

I feel hesitated to ask this question, but I cannot figure out a way to increase the performance. The problem is about running this featured example on a computer with both Intel HD GPU and Nvidia ...
7
votes
4answers
1k views

Mathematica gives wrong answer for an integral

When I execute the following, Integrate[ Exp[-w^2 + I w^3], {w, -∞, ∞}] I get (2 E^(2/27) BesselK[1/3, 2/27])/(3 Sqrt[3]) ...
2
votes
1answer
210 views

Manipulate for variable number of sliders

I'm trying to use Manipulate for plotting multidimensional data, where higher dimensions are defined as sliders. First, this simple example works: ...
1
vote
3answers
186 views

How to make list plot when all information is in a single list

I want to make a plot , where the data is structured like so { {"l1", "l2"}, n1, n2, n3} } The values in the inner sub list are labels which are associated with ...

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