# All Questions

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57 views

### Can't find the correct root for this equation

So I have this expression ...
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 ...
41 views

### How to put numerator and denominator in a canonical form?

I have the following expression that I obtained after some computation: ...
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 ...
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 ...
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 ...
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 ...
75 views

### How to mark a point on a graph?

So I'm obtaining the following graph: ...
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 ...
105 views

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. ...
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 ...
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 ...
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
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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
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: ...
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 ...
297 views
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### 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 ...
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 ...
23 views

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

Consider some dataset. I use the following code to interpolate it: ...
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 ...
38 views

### LogPlot Fibonaccinumbers from n to m [closed]

I want to draw the Fibonaccinumbers from 16 -116. ...
68 views

### Repeat every $x$ coordinate except the last one

Below is the code to print the x value. ...
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 ...
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 ...
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 = ...
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?
39 views

### How to specify that symbolic expressions are real numbers in Mathematica? [closed]

I have the following complex expression ...
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 ...
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 ...