All Questions

2
votes
1answer
107 views

Calculating the sum of the lengths and plotting all curves on the same map

I have a curve like below; ParametricPlot[ FromPolarCoordinates[{Exp[(t + 0)*0.5], t}] // Evaluate, {t, 0, Pi - 0}, PlotRange -> All] This curve rotates ...
1
vote
2answers
66 views

How can I extract blocks of 8 bits data from a plain text file?

I have a plain textfile consisting of 4M numbers (0 and 1's) from the number Pi. I would like to split this textfile into blocks of 8 bits (ie 8 characters). I know this can be done with StringTake ...
-4
votes
0answers
31 views

What does orthogonall mean? [closed]

Say I have a node in a grid that effects all other nodes "orthogonally". If a node has a value of "4", than it increases the value stored in the other orthogonal nodes next to it by "1". So If the ...
4
votes
1answer
108 views

Setting Some Elements in a Matrix to zero

Assuming I have the a 5x7 matrix below: b = ((1, 4, 9, 16, 25, 4, 2), (36, 49, 64, 81, 100, 5, 1), (121, 144, 169, 196, 225, 8, 9), (256, 289, 324, 361, 400, 9, 5), (441, 484, 529, 576, 625, ...
1
vote
1answer
56 views

Nested Do loops with externally defined iterators

I want to be able to define a set of iterators for nested Do loops, such as ...
1
vote
3answers
66 views

3D Plot the result of local Minimize with varying parameter values

I'm faced with the following minimization problem: Find $r\in[0,1]$ that minimizes $\frac{d^2+k^2 (1-2r)r}{2(1-r)r}$, which is bounded by 0 and 1. In addition, $k<d$ holds and each of $d$ and $k$ ...
9
votes
1answer
113 views

Option Lighting in the Show function does not work

Bug introduced in 11.2 or earlier and persisting through 11.3 There are something wrong when I try to evaluate the example from Lighting Docs, here is the code: <...
2
votes
3answers
143 views

Force a sum to be simplified

I want to force this sum to be simplified to 1 Sum[Cos[(Pi*l*(2*m + 1))/(n + 1)], {l, 0, n}] Only DiscretePlot3D gives the correct result showing all point to 1
0
votes
0answers
37 views

Variable Plotted in 3d Space

I am trying to plot dose rate in 3d space in terms of r, theta and z. None of the variables are functions of each other they are just arrays of points with the following sizes: Dose 220x35 r 220x35 z ...
0
votes
1answer
35 views

Changing variables to obtain derivatives of new variables [duplicate]

Let's say that I have some symbolic expression of a function $x(t)$, and would like to obtain its derivative $x'(t)$. However, I also have the following two identities, $\xi = \omega t$, and $\eta = ...
4
votes
2answers
113 views

Simulating ndgrid function of MATLAB

I know that there has been an answer on meshgrid function of MATLAB. For functions involving more than 3 variables, this function does not work. In MATLAB, the ...
5
votes
1answer
73 views

Automatically rotate frame ticks labels

Say in ListPlot[Range[0, 1, 0.1], Frame -> True] I want the tick marks on the vertical axis to be rotated 90 degrees. How to do it automatically, preserving ...
0
votes
1answer
63 views

How to get function of “GaussianProcess” prediction?

I am a new user of Wolfram Mathematica. I need your help. Let's say I have three variables: x, y, z. I want to calculate the "z" depending on x, and y. In other words, I want to find a function for z ...
2
votes
1answer
69 views

Importing Data multiple times from the same File

I have a large data file (.txt) with bivariate data in the following form x1,y1 x2,y2 x3,y3 . . . xn,yn ---------F 0 x1, y1 x2, y2 . . . xn, yn --------F 1 . . . ...
2
votes
2answers
61 views

Elements Replacement

Please I need help on how to replace elements in a matrix with another elements. For example, I have a (5,5) matrix, and I like to replace elements from All rows and column 3 to 5, with zero. such ...
4
votes
3answers
226 views

How to create “Volumemesh” from closed “surfacemesh”?

Given a surface region (MesgRegion netz2D), for example ...
1
vote
0answers
32 views

Shortcuts in Wolfram Cloud

When I use the cloud version of mathematica, the shortcuts like "cntrl /" and https://reference.wolfram.com/language/guide/NotebookShortcuts.html don't work. I believe it is because the browser ...
0
votes
1answer
68 views

(Updated) How do I fix a Discretization error?

I am attempting to model a cross section problem from Calculus II using the general slicing method. Below is the working code to generate the "slices" of the defined problem; however, I would like to ...
0
votes
1answer
99 views

How can I remove a stochastic trend from a time series

I am having some troubles with removing a stochastic trend from a time series. I am carrying out a study on the US debt to GDP ratio. I noted that there's a smooth stochastic trend in the series. ...
8
votes
1answer
126 views

Security of SendMail

It's a little bit scary to hand over your credentials like this: I would like to know just how secure this process is. Is any way to ensure that mail sent from Mathematica is encrypted in transit and ...
1
vote
1answer
91 views
+50

Notation package with Traditional Form

I symbolize subscripted variables with the form TraditionalForm, to enable easy use of TeXForm as suggested here: ...
3
votes
2answers
66 views

How can I put common frame ticks on the leftmost of a row of graphics?

I have a function which plots a response behavior of model variables holding a reference value constant (the green dot in the examples below) over a common PlotRange (achieved by plotting the ...
0
votes
1answer
48 views

How to specify boundary condition in a system of PDE?

I have this system of PDE below. But upon running the code I get an error: R = 3.95; gamma1 = 0.2667; gamma2 = 0.35; This is the system of equations, initial ...
1
vote
0answers
46 views

Create a Weighted Region

I am trying the make (not super accurate, just for fun really) simulations of light curves, as just circles with various sizes and temperatures, then computing the ...
2
votes
1answer
45 views

Could not export TimeSeries to CSV [on hold]

I have tried the following code to export a TimeSeries to a CSV. This is using code from a similar post "Export TimeSeries[] to CSV or Excel". ...
10
votes
1answer
112 views

Why does Success[…][key] work and Failure[…][key] doesn't work?

I'm trying to figure out what is a quick way to add error reporting to my user defined functions. I was experimenting with Success and ...
1
vote
1answer
36 views

How to select the data in a given way?

Consider the data data = {{x1,y1,z1},{x2,y2,z2},{x3,y3,z3},{x4,y4,z4},{x5,y5,z5},{x6,y6,z6},...} with N rows. It can be divided into N/6 sets of 6 rows. I want ...
-2
votes
0answers
42 views

Text rotation in 3D is not possible , using rotation function

Question 1 I have a cube I wanted to the corners of the cube but the test was not properly able placed just using coordinate, I wanted to rotate the text, so I tried using rotation it works perfectly ...
0
votes
0answers
42 views

How to release a secure MMA-NB/CDF with restrictions/locks to the back-end code visibility

Intention is to distribute demonstration files just like Wolfram Demonstrations (mainly dynamic manipulations with assisting textual explanations based off on Numerical Methods course lectures). If ...
2
votes
3answers
112 views

Signal Processing [on hold]

The image above is the list plot of discrete data I'm working on. Please I need help on how to zero out all the high amplitudes signal from the data. That is all the data in areas circled, I want to ...
2
votes
0answers
57 views

Import columns from a long .txt file

I have to import columns 1,2,3, and 6 from a long (2 * 10^5 rows) file with this structure: ...
1
vote
1answer
52 views

I want to perform a simple tensorial contraction

I want to perform a simple tensorial contraction like, if KroneckerDelta[i, j] is contracted with some arbitrary tensor A_{lkj} (not-necessarily symmetric) it should give the answer as A_{lki}. Is ...
1
vote
0answers
28 views

How can I export the values of both the dependent variable and the independent variable? [closed]

This is the first time I am using Mathematica. I am trying to calculate the bandgap of a solid using the following script. ...
5
votes
2answers
718 views

Onion plot of a ball

Consider the following simple example. ...
2
votes
2answers
126 views

Fourier Transform to help guess with NonLinearModelFit

I imported some data in Mathematica which I cleaned a bit. This process went well. I also managed to plot it, and tried to take the Fourier transform of the data and plot it again. I'm not sure if I ...
2
votes
2answers
33 views

Format a table column with superscript and operator

I have two alternative forms of a simple table, both of which have problems: ...
3
votes
1answer
179 views

Easy code help about matrix. How to change the elements in a given matrix?

For example I have a matrix A[1,1]={1,2,3,4}; Now I want to change the second element of A[1,1] to ...
2
votes
3answers
68 views

Exponentials don't cancel numerically [closed]

I'm trying something essentially like N[Exp[-x]*(D[Exp[x*y^2], y] /. y -> 1)] After differentiation and y -> 1 there is ...
3
votes
0answers
60 views

Approximate Nearest Neighbors in Mathematica?

Is there any support for Approximate Nearest Neighbors (ANN) in Mathematica or third-party packages? I'm looking for a good implementation of locality sensitive hashing for applications where ...
0
votes
1answer
67 views

Different result in ContourPlot function using different version of Mathematica (?)

I tested "Elasticity with Mathematica" notebook (Mathematica 6) in Mathematica 11.3 and tested C05_stress_kirsch.nb, I added some trigger code to protected function in the tensor2analysis.m file, and ...
2
votes
2answers
101 views

How does one plot a 3 dimensional table of numbers?

I've just spent three hours searching the documentation and this website for an answer. I have a rank 3 tensor: t = {{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}} How ...
0
votes
1answer
29 views

Suppressing DateString Default behavior when parts of date are missing

By subsampling data from a Excel spreadsheet I have created a Mathematica dataset that I then seek to modify by applying various functions to the fields to convert these data into a different flat ...
4
votes
3answers
204 views

Converting a list of colors into an image

I want to manipulate colors, and merge the resulting vector and rasterize it into an image, controlling the resolution of the pixel. E.g. I tried to: But what I would like to have is an image of 3 ...
0
votes
0answers
59 views

Exporting JPEG images to PDF losslessly (without modifying them)

I have several JPG images each representing one page of document. I want to export them to PDF file but without re-encoding them. I am able to do it, but images are always modified by Mathematica. ...
0
votes
0answers
40 views

Equal relation doesn't work on RGBColor expressions [closed]

I am treating colours as variables, and would like to test if they are the same. I would expect : (RGBColor[1/255, 0, 0] == RGBColor[0, 0, 0]) to return <...
0
votes
2answers
70 views

Having Mathematica automatically plug in the values for a system of equations

I have a set of pairs, such as {{8 a, 2 + 2 a}, {8 b, 1 + 3 a}}. This set encodes the fact that I want to put 8a == 2+2a and <...
3
votes
3answers
57 views

Merge pairs in a list that have the same 1st element by averaging the the 2nd elements

I'm trying to do interpolation on a large list of data of the format {{x1, y1}, {x2, y2}, {x3, y3}, ..., {xn, yn}} that is exported from a simulation. ...
0
votes
1answer
42 views

parameter fitting for a trascendental equation model

I want to solve the following problem with Mathematica: I have a physical model relating the $y$ variable with the $x$ variable given by the next expression: $$y=...
8
votes
2answers
382 views

How do I remove artifacts from my ContourPlot3D Valentine?

My version (below) of the "Valentine Formula" that appeared in today's New York Times, has some ugly artifacts that don't appear in the NYT (Java) version: How do I remove these artifacts? ...

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