5
votes
0answers
69 views

Why DSolve doesn't handle duplicate boundary condition

This code works well. DSolve[{y''[x] + 10 y'[x] == 0, y[0] == 0}, y[x], x] (*{{y[x] -> 1/10 E^(-10 x) (-1 + E^(10 x)) C[1]}}*) But why mma gives ...
1
vote
0answers
131 views

Demonstration of an arbitrarily oriented and translated ellipsoid

(Edited and modified) After the advice I received I modify the post. I have created the following code for depicting an arbitrarily rotated and translated ellipsoid, along its ellipsoidal axes and ...
4
votes
1answer
58 views

How to canonically reorganize a list using only a limited set of manipulations?

I want to canonically reorganize (like Sort) a sequence of four objects seq[a,b,c,d], but the only manipulations allowed are <...
1
vote
2answers
55 views

Insert several rows and problem with Return

I wanted to write myself a function that makes it possible to Insert several rows into one list. ...
41
votes
2answers
2k views

Memoization with pure functions?

Is this possible? If I have a simple function, say: f=If[#>0,1,2]& then for each value of # this will re-evaluate f right? Is it possible to define a ...
2
votes
1answer
203 views

NMaximize with Nelder-Mead method fails to convergence when tolerance set too high

Recently I have been working on a optimization problem for which I use NMaximize with Nelder-Mead method. In general, I have to check a lot of systems which are built automatically. I want to skip ...
4
votes
1answer
83 views

JSON export truncates numbers to 6 digits of precision

It seems that in version 10.0.2 and 10.1.0, floating point numbers are truncated to only 6 digits of precision when exporting to JSON. Example: ...
0
votes
1answer
68 views
0
votes
2answers
126 views

How may I define e.g. Tilde[x,y] to have certain properties?

I would like to define, e.g., the Tilde[x,y] operator to have certain properties, and then investigate whether certain expressions involving that operator are True or not. For example, if I specify ...
2
votes
1answer
217 views

Mathematica equivalent of `qnorm` or `invNorm`

In R and TI-89 you can do qnorm(prob, mu, sigma) or invNorm(prob, mu, sigma) to get a value of ...
0
votes
1answer
64 views

Solve not returning anything

I have the following function: ...
5
votes
1answer
361 views

Why does DSolve give a different result than NDSolve?

When I try DSolve to solve a system: ...
26
votes
2answers
2k views

Trying to Visualize a Collatz - The Collatz conjecture

I happen to have this collatz collatz[x_, y_] := If[x == 3*y || x == 2*y + 1 || y == 3*x || y == 2*x + 2, 2, 0] So i want a visual 3D adjacency graph of my ...
15
votes
1answer
731 views

Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these ...
1
vote
0answers
51 views

How to replicate drawing applications' Quad-View playing with MatrixView?

I'm having trouble in figure out how to set the ViewMatrix in order to replicate the Quad-View that is available in drawing applications such as Blender. In these packages, if I drag the point of ...
1
vote
1answer
73 views

Writing to a serial device failing mysteriously

I have a device which communicates with the computer through serial. The device waits until it receives the character 'a', and then begins to stream data. I have been able to connect to the device and ...
2
votes
2answers
138 views

Convert List of Airport Codes to Entities

I have a list of airport codes: airports = {"ABE", "ABI", "ACT"} How can I convert this into a list of entities in Mathematica? Is this possible? I tried: ...
4
votes
1answer
71 views

How to add margins to a grid cell?

I was not able to figure out how can I add some space (margins) surrounding just the "a" and "b" strings of the following grid: ...
1
vote
1answer
81 views

I want the length 3 words on alphabet {0,1,2} with no two consecutive 1's [closed]

I tried this code but it doesn't work. DeleteCases[Tuples[{0, 1, 2}, 3], {_ 1, 1, _}].
0
votes
1answer
212 views

Prime number The Ulam spiral [closed]

I want a simple method of visualizing the prime numbers that reveals the apparent tendency of certain quadratic polynomials to generate unusually large numbers of primes. I was able to display the ...
0
votes
1answer
317 views

Numerical integration converging too slowly

I must solve this integral which I suppose to be a very small number. How can I do? When I wrote this code: ...
2
votes
1answer
139 views

ToElementMesh fails on DodecahedronIcosahedronCompound

Context I would like to compute the eigenmodes of a DodecahedronIcosahedronCompound. Why? Because it is cool! and I wonder how it rings… Starting with: ...
14
votes
3answers
353 views

How to convert a surface into a solid

Context I am interested in converting surfaces into solids (so I can make a 3D mesh out of them using ToElementMesh) Say I have the following cool surface ...
2
votes
3answers
162 views

Simplifying Logs assuming arbitrary arguments real and positive

I have some expressions involving Logs which I would like to simplify. Unfortunately FullSimplify doesn't work because it assuming the arguments are general. I have no way of knowing a priori what the ...
18
votes
4answers
899 views

How to define a recursive pattern?

I want to translate this recursive syntactic definition into a Mathematica pattern1: $$ \mathtt{x}: \begin{cases} \text{Null}\\ \{\textit{integer}, \mathtt{x}\} \end{cases} $$ In other ...
6
votes
1answer
173 views

How to do automatic differentiation?

Does Mathematica have any AD functionality or does it only support symbolic differentiation? If not, are there any packages or other third party implementations available? Edit (J. M.) Here is an ...
0
votes
0answers
54 views

Sharp Ratio Maximization, Closed Forms

I am trying to get a closed form for the following first order conditions (n=4): Here's the nb-File. The code is as follows: ...
1
vote
0answers
69 views

Learning mathematica, ListPlot [closed]

I am trying to teach my self Mathematica. I am working with the following example: ...
3
votes
1answer
145 views

Plotting country as a polygon

I am trying to reproduce an example from Geographics. GeoGraphics[Polygon[Italy]] It does not work. Using Ctrl+= this way: ...
2
votes
1answer
125 views

Arrangement Order and Multiple Columns Sorting Order of Associations with Missing Keys

I have the following well-formed JSON string ...
1
vote
0answers
105 views

How to Import .ibw files in Mathematica

Can anyone tell me how to import .ibw (igor binary wave) into Mathematica?
4
votes
1answer
189 views

How to automatically align multiple legends in Show [duplicate]

I am looking for a way to align two multiple legends while I can control the position of one of the legend myself. Consider the following code. ...
0
votes
1answer
54 views
2
votes
0answers
59 views

Importing HTML loses the Nested tags relation

...
1
vote
0answers
63 views

Sub-processes (like XML.exe, GZIP.exe) not ended properly

I have difficulties with running MathKernel.exe from .NET and sub-processes like XML.exe and GZIP.exe, which are not terminated properly. Sometimes even the MathKernel.exe task stays active and is ...
6
votes
1answer
365 views

Algorithms behind implemented Mathematica functions [duplicate]

When I use Mathematica for analysis and I write a publication, readers often ask me: "What is the algorithm behind your calculation?". I answer that I did it with Mathematica and if they are ...
1
vote
0answers
58 views

Why has FreeQ a quadratic complexity with high depth?

I am a little puzzled by the following test: ...
-1
votes
3answers
354 views

Cartesian equation of star shape

I need Cartesian equation of the following star shape. As i want to use its Cartesian equation for Plot3D.
0
votes
1answer
59 views
0
votes
1answer
56 views

Trouble in finding instances of values of variables that satisfy an inequality

Consider the following mathematical expression with complex numbers (phasor) and two variables (lambda and ia2): ...
2
votes
1answer
115 views

Precision of LinearModelFit with Polynomials

I have a Problem regarding the fit of given points with a polynomial up to the fifth degree. tableofvalues=Import["tableofvalues.csv"] My polynomial is: ...
0
votes
0answers
99 views

Mathematica keeps crashing my machine — is there a way to prevent Mma from eating up so much system resources so this doesn't happen? [duplicate]

Fairly often Mathematica crashes on me. I'm pretty sure I'm not doing anything too radical or unusual, but I'll try to run some program and it'll be taking too long to evaluate, so maybe I'll hit alt+....
2
votes
1answer
97 views

How to change size of slider in Manipulate?

I have Manipulate function with a few horizontal sliders. When I call ImageSize->Small in Plot within my Manipulate only plot of function is resizing and sliders are still big, so I'd like to make ...
1
vote
1answer
45 views

MUnit tests for aborted during evaluation

I would like to create unit tests, where the function is expected to generate $Aborted, e.g. because it was given wrong input. However, I don't see a way how to ...
4
votes
1answer
84 views

Why does TreePlot ignore the vertex labels in a TreeGraph argument?

Example (watch the vertex labels): aTree = TreeGraph[{"a" -> "b", "a" -> "c"}, VertexLabels -> "Name"] ...
1
vote
1answer
259 views

Plotting a best fit line for listloglogplot data

After playing around with calculating the Overlapping Allan Deviation for my research project (and with much help from this community), I have finally resolved a correct listloglogplot for simulated ...
4
votes
3answers
167 views

Graph generation from a non-paired edge list

The elements in e = {{6414, 6598, 6927}, {7, 1035, 2382, 6927}, …} are the graph nodes; for example, {6414,6598,6927} is ...
3
votes
0answers
35 views

Collaboration / refererencing in the notebook environment (without Workbench) [closed]

Discussing with my co-authors over the phone, I often find it hard to point out a specific input/line/part of a notebook. (I am not using Workbench) The input numbering "In[1,...]:=" helps but ...
8
votes
3answers
293 views

NIntegrate of surface area of intersecting spheres yields zero

I have a bunch of spheres (it's actually diamond cubic structure. The 0.6 radius doesn't matter), ...
0
votes
0answers
187 views

Normalized, symbolic Eigenvectors without abs(), sign() etc

I'm trying to compute the normalized eigenvectors of a matrix M = {{0, 0, 0, 0}, {0, 0, M5, 0}, {0, M5, 0, M4}, {0, 0, M4, 0}} If I try Normalize ...

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