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1
vote
1answer
57 views

Can't find the correct root for this equation

So I have this expression ...
1
vote
1answer
29 views

Reading specific data from files

I have a huge number of identically formatted .txt files. I would like to read some numbers at a specific position within the text file (row x, column y..) and put them in another file, then repeat ...
1
vote
1answer
41 views

How to put numerator and denominator in a canonical form?

I have the following expression that I obtained after some computation: ...
0
votes
0answers
46 views

Optimizing a parameter space search

This is related to my previous question: Solve for parameters so that a relation is always satisfied The Problem I am searching the parameter space of a large (many terms) function to find where the ...
5
votes
2answers
173 views

Solve for parameters so that a relation is always satisfied

Let's say I have a function parameterized by a number of variables. As a simple example $$F(x,y) = ax^2 +by^2-cxy+1$$ I want to find some set of values (doesn't really matter what they are) for the ...
2
votes
2answers
111 views

How can I evaluate a certain integral numerically?

The problem arises as value of $\gamma_0$ is very high (on the order of 10^13), whereupon $\exp (-\gamma_0\,h_a^2)$ is becoming very small and ultimately zero. Can anyone help me to evaluate this ...
1
vote
1answer
103 views

Desktop vs. Cloud option, home plan vs. basic plan: syntax differences

I do not understand why the following simple expression is accepted using a browser (cloud option), but is not accepted using the installed software (desktop option) with the plan basic of Wolfram ...
1
vote
1answer
75 views

How to mark a point on a graph?

So I'm obtaining the following graph: ...
1
vote
1answer
830 views

Solving coupled PDE and ODE

I want to solve a system of partial differential equation in Mathematica. equation is: $ y_0 = 0.5, t_0 = 30, λ_{12} = 0.3, λ_{13} = λ_{23} = 0.01, λ_{21} = 2.8 $ I am new in Mathematica. Please help ...
0
votes
1answer
105 views

Zeros or minima of a multivariable function [closed]

what is the most reliable method for finding the zeros or at least the minimum of $f(x,y,z,w,r)= - \frac{3}{96 \pi^{2}z^{4}} \int_{y}^{\infty}\sqrt{x^{2}-y^{2}}x^{2} e^{-x} dx+ \frac{3}{16 \pi^{2}(1-r^...
0
votes
0answers
30 views

Bad graphics of Mathematica 10.3 in Ubuntu 20.4

I just installed KDE (5.18.5) Ubuntu 20.04 in my computer and tried to install Mathematica 10.3 aswell. Note that I previously use Ubuntu 18.4 and everything worked well. Now, after I installed ...
0
votes
1answer
35 views

How can conditional expressions be used in calculations?

I have a fairly simple system whose solution involves conditional expressions. The system is ...
1
vote
1answer
45 views

Best way to get handle on the Ticks properties

There are a lot of questions already on Ticks. However I did not find a better way to handle ticks place, size etc. I have a simple example where I want have some ...
1
vote
0answers
31 views

How to define a divergence-free vector or a traceless tensor in xAct?

I'm trying to implement a Friedmann-Lemaître-Robertson-Walker metric + a perturbation in a scalar-vector-tensor split in mathematica, using xAct. The S-V-T decomposition comes with some rules for the ...
0
votes
0answers
28 views

How to call LabVIEW's .vi files in Mathematica?

I want to use Mathematica to process the data collected by LabVIEW, is there any way to implement Mathematica's call to LabVIEW's .vi files?
3
votes
2answers
114 views

How to efficiently check if a matrix is a Toeplitz Matrix

With ToeplitzMatrix we can create a Toeplitz matrix from a list of values. I have a question going in the opposite direction, namely, how to efficiently check if a ...
2
votes
0answers
22 views

NMinimize to ignore arguments for which function is complex valued [closed]

I'd like to minimize a pretty complicated function $f(x, y, z)$ with NMinimize, however for certain values of the arguments $f$ becomes complex valued, and my ...
1
vote
0answers
40 views

Reading product of same ByteArrays

I am handling a huge set of data and I am trying to optimize my code. I have very large expressions to expand and simplify and I've seen that converting the expressions to ByteArrays improves a lot ...
2
votes
1answer
98 views

Help with creating the NetChain

I'm trying to train a network to take 3 integers and give an output = Max/Min. For example {10, 20, 30} -> 3. But I cannot get the setup correctly. I must be missing something. ...
1
vote
2answers
173 views

How can I check if one expression implies another?

Say I have one expression, for example $x^3-3 + c = y$, and I want to check if it implies another with some set of explicitly stated assumptions. With the previous example, assuming all variables are ...
3
votes
0answers
68 views

How do I get built-in functions to use custom objects as if they were e.g. List?

(This is part 2 of my earlier question, Can I overload Part for specific heads (a la overloaded array subscripting)?, which was well-answered as asked.) Overview: My goal is to create a custom object -...
1
vote
1answer
77 views

Can I overload Part for specific heads (a la overloaded array subscripting)? [closed]

Mathematica/Wolfram Language newbie here. The behavior I am after is to be able to "overload" the subscripting of me-defined objects/Heads and thereby use them as if they were ...
4
votes
4answers
44 views

Double contraction between 2nd and 4th rank tensor

I would like to compute the double dot product between a 2nd and 4th rank tensor in mathematica $A_{kl}A_{ijkl}$ $if \, A_{kl}=\begin{pmatrix} 1& 0 & 0\\ 0 & 1 & 0\\ 0&0 & 1 \...
4
votes
1answer
31 views

How can I let the length of a vector in VectorPlot be represented by it´s norm?

I would like to draw a vector field and let the magnitude of the vectors change over time (t) using the Manipulate function. The direction of the vectors will be static. ...
0
votes
1answer
53 views

How can I make an FFT in Mathematica using data from a file? [closed]

I need to calculate the seismic moment of an earthquake data, but I don't know how the FFT is applied in some data, my data is a plain text that I must import it to Mathematica ...
0
votes
0answers
10 views

ToCTensor does not respect symmetry of tensor

If I try to convert a tensor object to a CTensor DefTensor[F[i, j], M, Antisymmetric[{i, j}]]; Fc = ToCTensor[F, {ch, ch}] The output is ...
0
votes
0answers
26 views

Find fit distribution of Normalized Histogram [closed]

I need to find a function to fit an histogram with "Probability" setting: Histogram[data,Automatic,"Probability"]. Thanks
3
votes
1answer
35 views

Probability Generating Function(s)?

I'm very new to Mathematica and I have started to use it since I have been tackling some Physics related problems(I'm an engineer by training). Specifically, I'm dealing with Master Equations and one ...
1
vote
1answer
12 views

Contracting a Tensor with a CTensor in xAct

I'm trying to contract two tensors that I made in xAct to get a simple result. First I set up a Cartesian space ...
0
votes
0answers
23 views

Problem wiith If statements inside For loop [closed]

Consider If statement If[1 == 2, 1] which is false and so does not evaluate, and If statement If[2 == 2, 2] which is true ...
2
votes
3answers
35 views

Select element in a multidimension list containing one element

Imagine that I have a list like: list={{{{1}}}} To access the number 1, I could do list[[1]][[1]][[1]][[1]] Of course it is very ugly but this is how I would do it ...
1
vote
3answers
293 views

How can I use procedure, circle3D, to make an animation of the osculating circle of a parametric curve?

I try to use circle3D procedure, shown below, to make an animation of the osculating circle of a parametric curve. ...
1
vote
2answers
55 views

How do I export a movie in AVI or Mov without altering the color and resolution?

Lossless movie export. How do I do that ? Or how do I export such that the color doesn't change. AVI makes changes the color and mov changes resolution and color. If you export a still image (in BMP ...
1
vote
0answers
23 views

GridLines missing using SciDraw

Does anybody know how to include standard GridLines in SciDraw? I found this but it doesn´t really answer the question. Here my minimal example reproducing the problem: ...
1
vote
1answer
23 views

How to share multiple “tagged” functions (symbols) like f[a][b] in parallel kernels?

I would like to give some context: I need to analyse many data sets stored in files using different kind of analyses. To keep track I like to tag each results of my analysis for example like ...
13
votes
1answer
297 views
+400

How to segment rectangular photographs on a table?

Given an image of a table with photographs (take from any angle), I'm trying to extract the photographs and correctly align them into perfect rectangles. There are four steps to the algorithm: Detect ...
6
votes
1answer
79 views

Undefined Indexed Variable

I searched already a lot about indexed Variables, and it tends to be the most applicable way to use tensor notation. But I am having a hard time to solve for undefined indexed variables: Here my ...
1
vote
0answers
23 views

Why does the InterpolationPointsSubdivision method fails to calculate this integral correctly?

Consider some dataset. I use the following code to interpolate it: ...
0
votes
2answers
86 views

How to save in STL format for 3D printing

I have the code of a spherical gyroid written in Mathematica and I am unable to save it in STL format. The image is shown in the figure below and the code is shown below. I need help with a code on ...
1
vote
0answers
38 views

LogPlot Fibonaccinumbers from n to m [closed]

I want to draw the Fibonaccinumbers from 16 -116. ...
1
vote
2answers
68 views

Repeat every $ x $ coordinate except the last one

Below is the code to print the x value. ...
3
votes
2answers
118 views

Change the color of sub-expression when the whole expression evaluates to a different expression

I found it's tricky to colorize a sub-expression of an expression that changes to a different expression when it is evaluated. For example, if I replace s with ...
2
votes
1answer
55 views

How to set colors for the customize contours

I am trying to beautify a contour plot where I have a wide data range. But still I want to use a linear scale for axis. But due to large range of the data, the most of the contours are restricted to a ...
1
vote
1answer
39 views

How do I find the maximum of a certain complex expression? [closed]

I have this expression: TFilter1 = -(7.5438*10^8/(6.34731*10^8 + 48270.2 s + s^2)) where s is a complex variable give by $s = ...
0
votes
1answer
38 views

How do I find the solution of a system of Diophantine equations in two variables? [closed]

If the first equation is 2x+y=152, and the second is x+2y=100, and it is a fact that both variables are whole numbers and x is larger than y, what is the value of x?
0
votes
0answers
39 views
3
votes
2answers
326 views

Nonlinear system of ODEs with boundary conditions

I'm trying solve this problem: g'(r) = a(r)g(r)/r, (1/r)a'(r) = g(r)^2-1 which have the following boundary conditions: a(0)=n ...
2
votes
3answers
343 views

How to use pipe operator in Mathematica?

t = Table[i1 + i2 i3, {i1, 2}, {i2, 3}, {i3, 2}] ArrayDepth[t] How to use "pipe operator" in Mathematica Version 11.0? In R, with library ...
0
votes
0answers
22 views

Symbolic expression of group delay [closed]

So I'm trying to find the symbolic expression of the group delay of this complex function: TFilter=(K1 wp1^2)/(-w^2 + (i*w*wp1)/Q1 + wp1^2) My attempt was to first ...
5
votes
1answer
258 views

Right syntax to launch multiple kernels on SLURM cluster

Important: sometimes you may need to modify the kernel location. In my case I had to find the kernel location explicitly by executing which wolfram command in the ...

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