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0
votes
1answer
14 views

Fourier and Table to evaluate coefficients

How can I use the DFT to evaluate the N Fourier coefficients using Fourier[] and Table? Where (N=2^5, it is the number of ...
0
votes
1answer
12 views

How to make FindRoot work with PolyLog functions

I have the following code: ...
5
votes
3answers
27 views

Nested Map. Iteration over a list

I am trying to add an element to a nested list. An example of the nested list is given below: cordxy = {{{1, 2}, {3, 4}, {5, 6}}, {{7, 8}, {9, 10}, {1, 2}}} I ...
1
vote
0answers
14 views

Fast Evaluation of a series of dot product

Context I have a function that depends on 3 real variables x,y and z and that is defined by a series of matrix products. The evaluation of f for a specific (x,y,z) is fast ~0.02 sec but I want to ...
0
votes
0answers
8 views

How to apply GeometricTransformation to ArrayPlot?

In a previous version of Mathematica (maybe version 7), it was possible to use GeometricTransformation on an ArrayPlot. That ...
0
votes
0answers
10 views

Mathematica gives invalid generators of a group?

...
2
votes
0answers
38 views

Problem with NDSolve and piecewise functions: Failure computing Filippov continuation

I am trying to solve a first order differential equation using NDSolve. The differential equation is ...
1
vote
0answers
19 views

Adding texture to thickened line

Continuing from here, I would like to Texture lines with thickness. I tried using the normal and the binormal from ...
0
votes
2answers
85 views

Converting Strings to Reals in a List

I am new to Mathematica and working with streamed data: ...
2
votes
2answers
60 views

Mathematica Code to create geometries

I want to create geometries. How to create shapes like this in Mathematica?
1
vote
1answer
131 views

Recreate specific plot in Mathematica

Can anyone help on this ? I did this ...
0
votes
1answer
17 views

FindMaximum::eit: The algorithm does not converge to the tolerance of _4.806217383937354`*^-6_ in _500_ iterations

code for calculate parameters (https://i.stack.imgur.com/eVoi6.jpg) The value of parameters (https://i.stack.imgur.com/1O8wL.jpg)
26
votes
5answers
7k views

sprintf() or close equivalent, or re-implementation?

Is there a sprintf() command (some command that takes a printf-style format string and a list of values to insert into the ...
2
votes
1answer
78 views

How to represent DiracDelta?

I need to represent δ(t-t0). The hint is: In cases involving Dirac delta functions, onemay use the regularized delta function δ(t) = ε/[π(t^2 + ε^2)] approaching δ(t) in the limit ε → 0^+. But I don't ...
0
votes
2answers
56 views

How to get the right approximation for a harmonic series?

The right numerical value of the closed form of $\sum_{n=1}^\infty\frac{4^n H_n^2}{{2n\choose n}n^2}$ is $40.66752074791188333...$. I tried to verify this result on Mathematica using the command: <...
2
votes
0answers
97 views

Does anyone have a Mathematica implementation of the standard $\arg\zeta(s)$ function required to evaluate $S(T)$?

This question is related to my question Is there an elegant exact formula for the zeta zero counting function? on Math StackExchange. Question: Does anyone have a Mathematica implementation of the ...
0
votes
1answer
47 views

Problems With StreamPlot

I have the following vector functions: $$E=\left\langle \cos\left[\frac{\pi x}{5}\right]\sin\left[\frac{\pi y}{4}\right], \sin\left[\frac{\pi x}{5}\right]\cos\left[\frac{\pi y}{4}\right], \sin\left[\...
2
votes
1answer
52 views

Find all non-isomorphic trees with $n$ nodes

I would like to compute all non-isomorphic trees with n nodes efficiently. I use the following approach: I create all possible trees ( Visualizing Cayley's Formula in Mathematica) and filter the ...
0
votes
0answers
35 views

Composition of functions and operator forms of built-in functions

I am trying to replicate the behaviour of some of the built-in operator forms (for Map, Apply etc) but struggling to understand ...
0
votes
1answer
36 views

Dft to evaluate Fourier coefficients

Use the DFT to evaluate the N Fourier coefficients cs of fp(t), derived by sampling the following periodic functions: (a) fp(t) = cos^2(t) and (b) fp(t) with unit cell φ(t) = rect(t) and period ∆t = 3....
0
votes
0answers
16 views

Minimization using NMinimize

I have a system of ODEs say x'(t)=2 x(t)-x(t)y(t)-3 x(t) g(t), y'(t)= y(t)-2 x(t)y(t)- x(t) g(t) with ICs x(0)= 1, y(0)=1/2, say, for t_0 <= t <= t_f, where t_0 and t_f are start and final ...
-1
votes
1answer
58 views

I need help please [duplicate]

Can Anyone help I did this to get the same graph but ...
33
votes
3answers
2k views

How to Make a Sankey Diagram

I have two lists start = {{1},{1},{1},{2},{3},{1}} end = {{1},{2},{2},{3},{3},{1}} And I want to create a Sankey diagram. Which looks something like So, ...
0
votes
0answers
27 views

Calculating double integral bounded by domain in Wolfram Alpha Notebook

If I want to compute Double Integral on a given region(See attached Picture) How can I input this on Wolfram Alpha Notebook
0
votes
1answer
66 views

Can NDSolve be used for a system with number (+40) of equations?

I have 42 coupled differential equations (6 of them are PDE's). My system has 6 objects and an object have 7 coupled equations. Since these objects are interacting with each other, their coupled ...
0
votes
0answers
21 views

Generation of nested list

Does anyone know a better way get the output generated by this code: Table[Table[{b-a,b},{b,7}]{a,7}]
3
votes
1answer
144 views
+250

Prove $R^\top R = I_3$ and find skew-symmetric matrix $R^\top \dot R$

Consider the following operator defined over unit vectors of $\mathbb{R}^3$: $$R(u,v) = (u\cdot v)I_3 + hat(u\times v) + \dfrac{(u\times v)\otimes (u\times v)}{1+u\cdot v}$$ ...
2
votes
1answer
48 views
+50

Optimizing some code for WolframCloud deployment/publishing

I am working on creating a demonstration and came across an instance where my code works fine on my machine locally but breaks down when deployed to the cloud (so that it can be publicly accessed). I ...
0
votes
0answers
51 views

Plot a function with specific list of values and use manipulate

I have the following function: T[r_, theta_] := Cos[theta*\[Pi]/180]*r^2 which I would like to evaluate using predefined values of r from a function which I define ...
0
votes
1answer
35 views

Manipulating lists based on conditionals and 3D plotting the smooth surface that bounds a list of points

First of all I want to create a list of evenly spaceed points in a cubic region in $\mathbb{R}^3$. Then I want to keep the points in this list which satisfy a certain condition, i.e. a function that ...
10
votes
3answers
1k views

Mod[1.2, 0.2] is not equal to zero

Why doesn't the following expression evaluate to zero? In[1]:=Mod[1.2, 0.2] Out[1]=0.2 Edit: This is what I wanted to do: ...
4
votes
2answers
316 views

How to prevent Round with hidden fractions

I found a strange behavior in Round. If we try: ToString[Round[4.811, 0.01], InputForm] we get: 4.8100000000000005 When I expected 4.81 In order to get ...
0
votes
2answers
127 views

Why is Sin[2.0 Pi] = -2.44929 x 10^-16 and not 0.0?

Why does Sin[2.0 Pi] evaluate to -2.44929 x 10^-16 and not 0.0?
16
votes
23answers
1k views

Benchmarking with Mathematica v.12 for up to date comparison across different machines

I am planning to purchase a new computer especially to use for Mathematica programming purposes. Currently, I have MMA v.11. Could someone with Mathematica v.12 run the following benchmarking and ...
5
votes
1answer
440 views

DeleteCases messing with my mind

I'm losing my mind. Please tell me my laptop is doing weird things and not me. Or do I need to get committed someplace? ...
1
vote
1answer
83 views
1
vote
1answer
190 views

Program for efficient computation of given functional:

I need to plot the following functional with accuracy: $$ I(x,s) =\int_0^\infty\mathrm dy \frac{F(x + \mathrm iy,s) − F(x −\mathrm iy,s)}{\mathrm e^{2πy}-1}, $$ Where $ F(z,s) = \dfrac{1}{z^s\Gamma(\...
1
vote
0answers
33 views

RegionPlot3D incorrectly plots regions defined by memoized functions

RegionPlot3D incorrectly plots regions defined by memoized functions. A memoizer: ...
1
vote
1answer
39 views

HatchFilling between two data sets in LogLog scale for Mathematica 11.1

Need to fill the region between two data sets with colored hatched (\ || //) lines in LogLog scale. I use Mathematica 11.1. Apparently HatchFilling nor PatternFilling are available.
3
votes
1answer
48 views

How to Create a Shortcut to put a frame around an equation

I use mathematica for typing Physics and other notes. For important equations, I prefer to put a box around them. To do so I use either: Insert-> Typesetting -> Add Frame from the menubar ...
5
votes
0answers
40 views

AppellF1 calculation hangs indefinitely

The built-in AppellF1 function seems generally useless. For example, AppellF1[3/4, 1/2, 1/2, 7/4, (7 + 4 Sqrt[3]), (7 - 4 Sqrt[3])] hangs indefinitely on my system....
3
votes
1answer
33 views

Copy DateListPlot ticks in ListLinePlot (for large data)

It is not very surprising that plotting a PackedArray is faster to plot than a list of pairs (date, value), nonetheless the plotting time may be prohibitive with <...
0
votes
0answers
24 views

Exporting a three-dimensional graphic to EPS

I draw a three-dimensional graphic with the use of the command "Graphics3D". The graphic includs lots of solid and dashed lines. When exporting the graphic into the EPS format, the final ...
2
votes
2answers
37 views

Date ticks with SmoothHistogram3D

I would like to plot some data with SmoothHistogram3D, but one of the axis is date, and I would like the ticks to reflect that: ...
2
votes
1answer
67 views

Limit variable in NonLinearModel Fit to a list

I'm attempting to constrain the values of some of the model fit variables to a list of defined numbers. Here are a sample dataset and model. ...
2
votes
2answers
60 views

Solving a recursive equation iteratively (including PolyLog function)

I have the following equation which I want to solve: $$ I_D = [Li_2(-e^{V_D-I_D})-Li_{2}(e^{I_D})] $$ Here $Li_2(x)$ is the PolyLog function of order $2$. Is there a way to solve this equation ...
2
votes
1answer
87 views
+50

ImageData of an image section

How can I take the image data of the area around a max? ...
5
votes
3answers
822 views

Giving a custom style a colored gradient background

In Mathematica, customizing Sections, Subsections, Titles and so on, can be done with Format > Style > .... Changing the background color of a style is one of the things you can do. Here is an example ...
2
votes
1answer
52 views

displaying topological sort/linear extensions via labeled Hasse diagrams

Is there a Mathematica implementation/package that displays all topological sorts (i.e. linear extensions) of a partial order using labelled Hasse diagrams (nodes labeled with the appropriate ...

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