0
votes
2answers
48 views

Part::pspec error occured

I wanted to simulate a noise model on CCD sensors, so I did as below: ...
4
votes
2answers
103 views

How to define action of derivative (D) on a user-defined operator f

I have a symbolic function (which is in fact an operator) f[expr, x] where the second argument is a local variable for f (kind ...
2
votes
1answer
57 views

Disobedient RegionPlot3D

I faced a strange behavior of a RegionPlot3D. I am drawing a piece of a plane bounded by a parabola. This works: ...
0
votes
1answer
87 views

Data Fitting problem

I'm having this kind of data, and I know what possibly the equation is, i suspect this has a sine equation but the plot not really seems sinusoid. so what possibly the equation is so i can do the ...
0
votes
0answers
50 views

Solving a complicated integro-differential equation

I'm trying to solve the integro-differential equation: $-(1+z) H(z) \frac{d f_{i}}{dz} = J_{i}(E',z) - f_{i} \sum_{j} n_{\nu_{j}} \sigma_{ij}(E',z) + \int_{E'}^{\infty}dE~\sum_{j,k}f_{k} n_{\nu_{j}} ...
1
vote
1answer
39 views

How to see Monitor temporary cell with ParallelSubmit?

I have a function to load large files into a "HSQL(Standalone)" database for processing that uses Monitor to update the ...
0
votes
0answers
56 views

How do I interpret an certain expression? [closed]

I used Simplify to simplify some long expression and received pretty long simplified form. A part of the output (in Standard Form) is the following: ...
0
votes
2answers
143 views

Solving equation containing ArcTan terms

IN MY EDIT I DESCRIBE HOW I GOT TO THAT EXPRESSION AND THE ORIGINAL PROBLEM. I have this expression: ...
2
votes
2answers
78 views

Generating a list of file names

I have set of files in the format 20160615-1-0.asc, 20160615-2-0.asc,... 20160615-5-0.asc etc. The following commands can List the file names at once which can be used to import later. ...
2
votes
0answers
45 views

Web crawler: want to ignore login windows [closed]

I'm trying to make web crawler with Mathematica. ...
0
votes
0answers
56 views

Solve equations involving summation expressions in Mathematica

I am trying to solve the simple linear regression equation analytically in Mathematica (not using builtin functions). I managed to calculate the gradient as follows f is loss function using RSS and ...
3
votes
2answers
190 views

Selection of points based on position

I have a series of points, for example: points = {{0, 0}, {1, 3}, {2.5, 2.5}, {4, 4}, {6, 6}}; I want to join all points successively unless, for example, the y-...
15
votes
0answers
127 views

Any manual on cell grouping management?

Recently I come back to the problem of cell grouping and performed extensive search on this site and on MathGroup archive for information on how to use the possible values of the ...
3
votes
3answers
145 views

Question about Nearest [duplicate]

In the following example Nearest finds the nearest values between list1 and list2 and ...
16
votes
0answers
99 views

Inconsistent handling of Dynamic option values; intended, omission, or bug?

In answering Dynamic ClipPlanes calculated from current ViewPoint Kuba and I got into a brief exchange regarding how Option values wrapped in Dynamic should be ...
1
vote
2answers
107 views

Factor out imaginary unit of root of obviously negative term

Suppose I have the term $t=\sqrt{-a^2-b^2}$, where $a,b\in\mathbb R$. Of course, we know that it holds $$ t = \mathbb i \sqrt{a^2+b^2} $$ which is (in my opinion) more convenient. How can I get ...
-2
votes
0answers
35 views

How to compute a integrate a triple integral? [closed]

I have tried to compute this triple integral but I keep getting an error. I have attached a picture of my code.
1
vote
1answer
125 views

Residue failed to reproduce this residue in a paper

This problem is a more clearly state of my original problem which is off topic, so I reconsider my problem carefully based on previous discussions, and gives the following valid code to reproduce my ...
1
vote
2answers
91 views

Group matrix values by column [closed]

Original Question: I have a list {{a, 1}, {b, 3}, {c, 1}, {d, 2}, {e, 3}}. I want to be able to group the the first number in each pair that has the same second ...
0
votes
1answer
59 views

Why is FindRoot failing to evaluate this function? [closed]

I have a (somewhat long) script which runs cleanly until the very last stage. Here, I'm using FindRoot to attempt to parameterize implicit curves in the zero set ...
2
votes
2answers
364 views

How can I evaluate a certain kind of summation?

I have the following sum P0, P1 and P2 are constants. The problem is to assign all ...
0
votes
1answer
63 views

Error message when running NDSolveValue

I am trying to solve a set of differential equations but keep getting an error. See message below "NDSolveValue::ndnum: Encountered non-numerical value for a derivative at t=0" The system that I ...
0
votes
1answer
56 views

Integral of $(\sin x)^3(\cos x)^3$ [closed]

For the integral of (sin x)^3(cos x)^3 I got 1/6(cos x)^6 - 1/4(cos x)^4 + C. This seemed to work but my book had 1/4(sin x)^4 - 1/6(sin x)^6 + C. This is similar to what I got but instead of cosine ...
2
votes
2answers
124 views

How to plot an Eddington-Finkelstein diagram

I need to plot the same thing as what is shown on the third picture of the site below (sorry, I'm unable to poste that picture here) : http://ion.uwinnipeg.ca/~vincent/4500.6-001/Cosmology/...
-2
votes
0answers
38 views

How to change the default icon of mathematica? [closed]

Is it possible to change the default icon of mathematica to some other picture ?
1
vote
0answers
53 views

Numerically parameterize portion of $F[x,y]==0$

I have a relatively complicated function of two variables F[x,y] whose zero locus contains a number of intersecting paths in the $x,y$-plane. A problem I've been ...
2
votes
0answers
61 views

Why does Expectation function compute, while explicit integration does not?

The code: Expectation[1 + 1/y, {y \[Distributed] ExponentialDistribution[1]}] outputs 1 - EulerGamma While, ...
8
votes
1answer
103 views

Calculating density of states from lists of momentum/energy data

I am trying to calculate the density of states for a 2D system given certain band structure data organized in a specific format. Below is an example of my procedure: Beginning with a simple 2 x 2 ...
2
votes
3answers
128 views

NDSolve and differentiation of Abs

I have found several questions about the derivative of Abs and how it is not defined in the complex plane. What I have not found yet is a precise and simple ...
25
votes
4answers
423 views

$3D$ graphic of soccer ball

How to make a soccer ball $3D$ graphic? The following image is from Wikipedia, Spherical polyhedron: Truncated icosahedron (left) and standard soccer ball (right) ...
6
votes
1answer
90 views

ArrayPlot gives wrong plot legend, how to fix?

Bug introduced in 10.0 and persisting through 10.4.1 My minimal working example is the code ArrayPlot[{{1, 0.1, 0}, {0.1, 0, 0}}, PlotLegends -> Automatic] ...
0
votes
1answer
41 views

Issues with Functions Defined as Eigenvalues [closed]

I have to calculate eigenvalues of 4 different matrices. The code I'm using is below, but essentially three out of the four are working with no problem, and one (the eigenvalues I've defined as y) ...
2
votes
1answer
100 views

Speeding iterative computation

I want to get the following iterative sequence ...
0
votes
0answers
5 views

How to derive a Taylor series from the ones we know (cosx, sinx, …) [migrated]

If we know the Taylor expansion for the cos(x) function around 0, how can we use it to derive the Taylor expansion of a similar function (cos(x+π/4)) around 0? I do know how to get the Taylor series ...
2
votes
2answers
56 views

How to use quantities obtained by solving equations directly to plot

I want to know how we could use the quantities we found by solving simultaneous equations, directly into plotting graphs. For example I have this Mathematica code; it gives the values of ...
3
votes
1answer
180 views

Alternatives to For/Do Loop to optimize indexing Matrix

I am trying to optimize my code that searches for elements in the rows of matrix that are greater than 0. Then use that position to grab the element from other matrix. I use the do loop to iterate ...
0
votes
0answers
15 views

No MenuBar despite CurrentValue[EvaluationNotebook[],WindowElements] saying it exists

I have 32-bit linux 14.04 (arch returns i686) with Mathematica 10 {$Version in Mathematica ...
0
votes
0answers
49 views

Symbolic series

Mathematica realises, of course, how to deal with symbolic series: Sum[g[x]^k, {k, 0, ∞}] (*Out: 1/(1 - g[x]) *) I.e. it does not worry about values of ...
0
votes
0answers
59 views

Are the following implemented: Differentiable, Continuous, Interior Point? [closed]

FunctionDomain is a great Mathematica function. It tells you the natural domain of an expression. Has anyone (or is anyone) working on a similar thing for checking ...
4
votes
2answers
64 views

Adding lines and labels at custom positions in BarLegend

Currently my BarLegend looks like: BarLegend[{(ColorData["Rainbow"][Rescale[#, {0, .125}]] &) , {0, .11} }] I would like to add white (maybe dotted) lines ...
1
vote
1answer
40 views

StreamDensityPlot plots arrows of different length

I am plotting a vector field with StreamDensityPlot. I know it's symmetric about the $x$ and $y$ axes because of the equation, but also because if I plot it with VectorDensityPlot, it shows the ...
2
votes
0answers
78 views

ListPolarPlot goes crazy when PolarAxes->True

Bug introduced in 9.0 and fixed in 9.0.1 I think I am experiencing the same/similar problems as this user. Mathematica Version: 9.0 for Mac OS X x86 (64-bit) (November 20, 2012) Computer: Mac OS ...
1
vote
1answer
58 views

Consecutive generation of subsets

It is well known that the array of subsets of even small set is very big. This leads to problems with machine memory. Is there an effective way to generate subsets sequentially?
0
votes
1answer
39 views

ListPlot[Transpose[{xx,yy}]] returns blank plot [duplicate]

This is complete mystery for me, but I am unable to plot the following data... I have two lists, that I want to ListPlot. The data is created in the following way (I edited the code for more clarity): ...
0
votes
1answer
46 views

I have a problem with particle in the box [closed]

I have a problem while generating particle in the box from this equation Plot[Sqrt[2/L] Sin[n Pi x/L], {x, -L/2, L/2}] because Mathematica might confuse about ...
3
votes
1answer
57 views

Plotting over the unit interval $[0,1]$ [closed]

Related to the question : Neumann and Dirichlet eigenvalue problem - Eigenfunctions on the square I'd like to do the same thing on the line instead of the rectangle, i.e. with $\sin(k\,π\,x)$ and $\...
0
votes
1answer
44 views

How to sum over half integers? [closed]

I have an expression of the form Sum[1 + x^n + x^(n^2/2), {n, 0, 10}] but I want to sum over half integers, that is, I require that $n \in \mathbb{Z}+\frac{1}{2}$ ...
5
votes
1answer
62 views

How can I generate a graph from a NetworkX JSON

I have done some network generation and analysis in Python NetworkX. I do most of my visualizations with D3, but for publications I would like to generate some graph plots with Mathematica as well as ...
3
votes
2answers
157 views

Operation with lists

I have created this code and was wondering if you could suggest a less convoluted way of solving the problem. I have two lists: ...

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