1
vote
1answer
79 views

Getting complex infinity for solution to differential equation

DSolve[y''[x] - (2 n + 1) (3 + 2 n) y[x]/(4 x^2) + \[Beta] y[x]/ x^(-2 n) == 0, y[x], x] I am trying to solve the equation and all I am getting is ...
1
vote
1answer
67 views

Generating a very large list of integers not divisible by a set of primes

I have read (58520), but the solutions there do not work when using a large maximum value because they rely on Range. For example, ...
0
votes
1answer
27 views

Using set of lists in if function? [on hold]

I have the following function: a3[m_, C_, St_, Stt_] := If[C > 0, (m*C)/St*Stt, 0] now my input for C, St and Stt are different set of lists. So I tried to ...
0
votes
1answer
61 views

how can I get the right derivatives in this Sum?

I want to get the derivatives of $q_i$ of the following function Q in Mathematica: $$Q=\sum _{i=1}^N q_i$$, Using the command of $$\frac{\partial Q}{\partial q_i}$$, the software give me an answer of $...
3
votes
1answer
71 views

Why does RegionUnion fail for these Regions?

Introduction Lately, I asked for a solution to inflate and unite a List of BoundaryMeshRegions: Inflate and unite a list of 0D to 2D regions JasonB came up with a ...
3
votes
1answer
126 views

1-D Graph in Mathematica

I'm trying to reproduce the solid blue graph on the left hand side in the following picture: The analytical expression for the graph is: $$ - \frac{1}{\tau} \ln \Bigg ( \Bigg [ \frac{|\eta|}{1 +...
0
votes
1answer
50 views

Integration with a matrix as the the integrand [on hold]

How can I calculate the following integral (wisely) in Mathematica? $\qquad \int^{2\pi}_0 \int^{\pi}_0 \int^{2\pi}_0 \mathbf{A}\,d\alpha\,d\beta\,d\gamma$, where $\mathbf{A}$ is a vector defined as: ...
3
votes
1answer
29 views

NumberForm NumberPadding outside of NumberSigns formatting

I am getting an unexpected result with NumberForm's NumberPadding option when specifying ...
0
votes
1answer
90 views

Plotting several 2D plots on one 3D graph [duplicate]

I know that there are some similar questions but I don't find the solution to my problem. I have made several 2D spectrum plots from data of txt files (colunm1 vs column2. Each one showing a plot ...
0
votes
0answers
35 views

Optimization of the process of obtaining a global stiffness matrix

I created this code in a detailed manner so that i can understand. However it is not optimized. I think that may be a bit confusing. Anyone who is interested in analyzing and understanding my ...
0
votes
1answer
32 views

Modifying a spacing of cells and background of a notebook

A simple question: How do I reduce this spacing and how to change the background? I think it is in the Options Inspector, but I cannot find the exact location to make the modification. As for the ...
2
votes
5answers
160 views

Intersection coordinates of two spheres

I am trying to obtain a list of coordinates at which two spheres intersect. Take for example the spheres: sp1=Sphere[{0, 0, 0}, 1] and ...
3
votes
0answers
25 views

Dynamic graphics appears first with wrong background [duplicate]

This is one of those annoying things that you put aside for years before making a post of it. Put a dynamic Graphics into a gui object (...
-6
votes
0answers
39 views

how to define a function as variable in mathematica [on hold]

how to define a function as variable in mathematica. please refer to attach picture. thanks.
2
votes
1answer
82 views

Duties of Threads accompanied by `#` or a Rule `->`

I was willing to understand the Coolwater's solution of the presented problem here. He proposed the below solution ...
0
votes
1answer
38 views

Mean brightness and the standard deviation of columns in a gray scale image

I want to calculate the mean brightness and the standard deviation of columns in a gray scale image (8bit). Can the following calculation code be made faster or/and shorter: ...
6
votes
1answer
268 views

Text on a plane without Rasterize

When I plot Text in Graphics3D it always faces the ViewPoint. I would like to put the text ...
3
votes
2answers
40 views

In which direction does WindDirection 0° point?

I was playing around with WeatherData. In this moment: WeatherData["Milan", "WindDirection"] (*0°*) which is nice, but 0°, ...
-1
votes
1answer
40 views

representing data for multivariate time series analysis

Please give a simple example of how to represent data for multivariate (vector) time series in Mathematica, so to use TimeSeriesModelFit?
-1
votes
0answers
55 views

Creating a Symbolic Singular Matrix

I am trying to differentiate an expression involving a matrix. When evaluating the input, Mathematica assumes the matrix is invertible, when it is not. How do I specify a symbolic singular matrix to ...
-1
votes
0answers
28 views

Force results from a W|A query expression in certain form

WolframAlpha["Weather"] selects a weather station following its own internal logic and I would like to overrule this selection with a different station of my choice. Is that possible? I think I read ...
0
votes
1answer
44 views

Inverse and Series Connection - TransferFunctionModel

I need to perform certain operations on individual transfer functions. As an example, ...
-1
votes
0answers
50 views

I can't install SavitzkyGolay package

I want install the package SavitzkyGolay.m that I've downloaded. I've tried with menu item file-install but not works. I need install this package for smoothing my datas. Is there another way to ...
11
votes
0answers
71 views

Can one effectively edit a Front End Resource that is already loaded?

A number of special definitions are loaded from .tr files on Front End initialization and are accessible via FrontEndResource. ...
1
vote
0answers
36 views
0
votes
0answers
64 views

How can I verify this limit? [on hold]

Hello I have to verify this limit $$ \lim_{N \to \infty} \frac{2 \pi}{N+1}\sum_{n=0}^{N}\sin^2(q_n)\frac{1}{E_n}\left [ \delta(\omega -E_n)+\delta(\omega+E_n) \right ] = \mathrm{sgn}(\omega) \Theta(1-...
4
votes
2answers
141 views

Change lighting in ChromaticityPlot3D

It looks to me like ChromaticityPlot3D has some default lighting, but unlike most Graphics3D functions the Lighting option doesn't seem to have any effect. However, the documentation states "...
11
votes
0answers
102 views

Handwriting recognition with Mathematica

I am trying to teach Mathematica to read my handwriting. Since I don't want to ruin my reputation by showing my own handwriting, I am going to use a font called blackjack. Lets say this is a ...
4
votes
1answer
70 views

Can I make IsomorphicGraphQ consider other properties besides the EdgeRules?

Consider two graphs, which are isomorphic to each other based on the vertices and edges, ...
1
vote
1answer
71 views

Tensors constructed using KroneckerDelta's - and/or displaying KroneckerDelta as a matrix

I am doing some work in elasticity and as a result am working with tensors. In particular, I would like to calculate the contraction of a fourth order tensor (the stiffness tensor) with a second order ...
1
vote
0answers
15 views

How can I distribute redefinitions of system functions to parallel kernels?

I'm having some trouble getting my parallel kernels to get wind of user redefinitions of system packages, and I'm looking for the cleanest way to do this - preferably using DistributeDefinitions. To ...
1
vote
1answer
66 views

Dynamic Plot of non-linear function within DynamicModule yields dynamically changing constant line instead of expected behavior

I'm having a problem with DynamicModule; the code below produces a plot with a line that changes value, based on the slider positions of the parameters, which is very nearly what I want; I would ...
1
vote
1answer
50 views

Fastest way to import a large undirected graph from .ncol format

Problem: I have a large undirected graph in the .ncol format, and want to get it in to Mathematica. I understand that Mathematica doesn't natively support the ...
4
votes
1answer
101 views

Mass distribution in NDSolve

I'm trying to model the solar system with NDSolve, basically a numerical n-body solution. I model the initial positions of bodies from a data set thusly: ...
-2
votes
0answers
37 views

Programing the Euler characteristic

The Euler characteristic theorem is a wonderfull theorem not only from the mathematical point of view but also from the scientific view point. Here is a version that I would prefer to program by ...
2
votes
1answer
40 views

How to read import VRML (.wrl) into Mathematica

I wonder if there is a way to Import VRML objects, e.g. here. The Export of These formats is provided but I did not found a way to Import it. Can anyone help here? (The Goal is to build a model of ...
0
votes
1answer
59 views

Underflow occurring in computation

I've got an "Underflow occurred in computation" problem. Here's a simplified version of the code: ...
1
vote
1answer
23 views

Can mathematica's GraphDistance handle complex weights? Or unknown parameters eg. 'x'?

The EdgeWeight property states that the EdgeWeight can be any expression and the GraphDistance function states that in a weighted graph, it will return the minimum of the sum of the weights. So if I ...
2
votes
0answers
56 views

Rationalize error

The docs state that "Rationalize[x,dx] yields the rational number with smallest denominator that lies within dx of x." However, testing this out it appears to be false. ...
0
votes
0answers
6 views

Please help with this C calculation [migrated]

Why I can not get a result of 2 while giving input of 2.2 as a float. With logic that 2.2 gets converted to 220, than when it goes through the first for loop I am going to get a remainder of 20(which ...
1
vote
1answer
67 views
0
votes
0answers
33 views

Parametric region instead of 3D plot when using parametric plot [on hold]

I want to draw a parametric region, that is, a 2d-graph using 2 parameters. However, each time I use ParametricPlot with 2 parameters, Mathematica interprets it as 3D plot. Not even the examples ...
0
votes
0answers
40 views

Solving linear system with non-commuting coeffcients

Is there a way to solve a linear system of equations where the coefficients do not commute? (Warning: my two-days of looking so far suggest this may be an unsolved math problem, but I figured I could ...
6
votes
3answers
106 views

Inflate and unite a list of 0D to 2D regions

I've got a List of BoundaryMeshRegions, created via ConvexHullMesh: ...
1
vote
0answers
127 views

What is the symbol FE`None for?

I have run into the symbol FE`None multiple times. What is this symbol, and what is it designed to indicate? All I could find is that FE indicates the front-end, but it's unfortunately a very ...
2
votes
2answers
191 views

Curve fitting with this modified integrated log-normal function and extracting fitted?

The data to be fitted is for y vs x. We have y and x points. We do not have data for w. In fact, w variable is being varied during integration from 1e-9 to 100e-9. The fitting parameters are Ms,sigma,...
0
votes
1answer
59 views

Coupled differential equation using NDSolve

I am using mathematica to solve a coupled differential equation using NDSOlve and stuck with it. Could you please help me out to figure out the solution. My problem is $$ A[\omega]:= A''[r]+\frac{f'[...
0
votes
0answers
38 views

Montgomery Modular reduction

I saw a Mathematica Implementation of Montgomery reduction at Montgomery Modular Exponentiation, a beautiful one by Simon Woods. I ran this in Mathematica and it was fast, but it does not give the ...
0
votes
0answers
24 views

How to get the numerical result of inverse CDF?

This is my code. And I want to solve the function which contains both Q and L. But Mathematica only gives me a result with "InverseCDF" function, but not a number? I'm not sure whether I use the code ...
0
votes
0answers
46 views

Line Curvature and Gaussian Curvature [closed]

Use Mathematica to calculate the curvature of the line: Then calculate the Gaussian curvature of the plane Ax+By+Cz=D, in which A, B, C, and D are constants and C≠0 Here are some ...

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