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Matrices of Machine- or Arbitrary-Precision Real Numbers Error While Using Arnoldi for Large Sparse Matrix

I'm trying to use the built in Arnoldi method in Mathematica to compute the first 1440 eigenvalues of a large sparse matrix. After importing ...
0
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0answers
6 views

Part specification is longer than object depth

I have a function called BasicEulerModified, that is fine(I think). However, when I run another cell to generate a list of ordered pairs, I get the Error "Part specification is longer than depth of ...
0
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0answers
4 views

Plot Venn Diagram of Boolean Formula with Mathermitca

https://www.wolframalpha.com/input/?i=%28a+and+b+and+c%29+or+%28not+a+and+not+b+and+not+c%29+or+%28not+a+and+b+and+not+c%29+or+%28a+and+not+b+and+not+c%29 How do you plot Venn Diagramm shown in the ...
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0answers
6 views

Function arguments are taking way too much RAM

I have to compute a function "func" with 24 arguments. Unfortunately when I apply the arguments the RAM fills up immediately. I even change the swap size of my Linux system to 100 G. I hope somebody ...
0
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0answers
16 views

Clustering or Grouping by list of similar strings

I have gathered some sports data from over 40 different sources. I now need to get all the games to "match up", "grouped", "clustered", or "aligned" so all the information for one game is in one list....
1
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2answers
39 views

Solving an equation approximately

I have a complicated equation in terms of $\omega$ and $\kappa$: ...
-1
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0answers
16 views

What is the fastest method to find a local minimum of a polynomial

I have high ranked polynomials for which I need to find local minima. Each polynomial has an increasing rank and only one minimum that is valid for the purpose. So from the lowest ranked polynomials I ...
1
vote
1answer
18 views

Applying functions to members of members… of lists of lists…, etc

Suppose that I have a list of depth $k$, and I want to apply a function $f$ to all elements at level $n$ - e.g. $f,\{\{\{a,b\},\{b,c\}\},\{\{c,d\}\}\},3\mapsto\{\{\{f(a),f(b)\},\{f(b),f(c)\}\},\{\{f(c)...
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0answers
22 views

Solving a System and taking inverse Laplace/Fourier Transforms

I have a set of linear equations for 4 quantities which have been both Fourier transformed and Laplace transformed. The system needs to be solved for the quantities and then each of the quantities ...
2
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3answers
33 views

Find minimum with matrix positive-definiteness constraint

Say I wish to find the minimum value of the determinant of a symmetric matrix under the condition that the matrix be positive definite. So I attempt: ...
3
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0answers
18 views

Is it better to use a single binary operator in each Assumption entry?

I am trying to understand why FullSimplify[x^a < 1, {0 < x^a < 1}] does not simplify but ...
0
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0answers
43 views

Sum all the elements of a column

I have created the matrix m and I am not able to sum all the elements. {1, 2, 3, 4} would give 10 for example. Can anybody help? Best,
1
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0answers
32 views

Boole Simplifcation

If you submit this to WA https://www.wolframalpha.com/input/?i=%28a+and+b+and+c%29+or+%28not+a+and+not+b+and+not+c%29+or+%28not+a+and+b+and+not+c%29+or+%28a+and+not+b+and+not+c%29 and expand the ...
0
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0answers
10 views

Taylor series approximation of Error function on complex domain

I am using Taylor series to approximate error function on complex domain. For a given $z\in D\subset \mathbf{C}^1$, we know the Taylor series of error function (around point $z_0=0$) is uniformly ...
1
vote
1answer
19 views

Inactivate Controls within Manipulate

Given a certain Control object (checkbox, for example) within a Manipulate environment, my goal is to define another control ...
1
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0answers
30 views

Cache a function in mathematica

I have a function of one variable $f(x): \mathbb{R}\to \mathbb{C}$ which is very difficult to evaluate. Single evaluations may take hours, and I need to use the function at a large variety of points. ...
1
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0answers
16 views

Parallelization of MATLink - Calling user defined MATLAB functions

I am attempting to run parallel finite element simulations in Mathematica using the AceGen & AceFEM softwares in conjunction with a MATLAB script called from Mathematica. I am able to run some ...
0
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0answers
20 views

How can i speed up NDSolve

I have written a simulation that solve a pde, I used a method I found on this site to speed up the calculation but it is still slow. Is there any way to speed up the prosses? ...
0
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0answers
19 views

3D surface plot difficult to put axis ticks and lables

I have a surface plot, I wanted to fix the axis labels and ticks to this plot, but I am unable to fix this. How to do this, Here is the code I tried. the x-axis limits 1e-3 to 1e12, and Y-axis is also ...
0
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0answers
11 views
3
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1answer
47 views

How to Refine HeavisideTheta or UnitStep?

Look at the following chunk of code: Assuming[x > 0, Refine@HeavisideTheta[x]] It yields 1. However the same method does ...
3
votes
0answers
21 views

How to fix the legend and dotted edges in WolframCloud?

Following the problems in my previous question: How to get good images for Graph in Published Notebooks I found a way to fix the aliasing issue, apparently, the ...
2
votes
2answers
28 views

Extract Velocities from Qualified EntityValue output

I have following statement: EntityValue["Planet", "VelocityAroundSun", {"Date" -> DateObject[{2020, 2, 19}, "Day", "Gregorian", 1.]}] and get the required ...
-2
votes
0answers
38 views

Boltzmann Equations [closed]

How to solve a coupled Boltzmann non-linear differential equations that one encounters in cosmology? For example-
1
vote
1answer
19 views

xAct working with an unspecified function

I am trying to use xCoba with a diagonal metric depending on an unspecified function f[r], but I get the errors: CTensor::...
1
vote
2answers
58 views

Pick out elements from a list of lists using criteria

Consider a list of lists in this form (with a shape $ m \times n \times 3 $): ...
-1
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0answers
36 views

How do you plot an integral on mathematica? [closed]

How do I plot this integral on mathematica? I am trying to do this by hand but want to check on mathematica to see if I am doing it correct.
3
votes
2answers
38 views

How can I make ListDensityPlot show up only in a specified region?

Disclaimer: I am new to Mathematica and this is my first post here! I am trying to plot EEG data of different intensities of brain waves from an FFT to areas of the brain where they were collected. I ...
2
votes
0answers
27 views

Connect Raspberry pi front end to remote kernel(s) (Ubuntu, the free Wolfram engine)

I am trying to connect a Raspberry pi front end (notebook) to a remote kernel running Ubuntu with the free Wolfram engine. I have researched this answer but it never worked. Using the code below I ...
2
votes
1answer
48 views

How can I find all polynomials that fit an equation?

How can I ask Mathematica to find all polynomial $ f \! $s such that, for a constant $ k $: $$ f(x) \ f(y) = f(x) + f(y) + f(xy) + k $$ I've solved it on paper and want to check my results. I've ...
0
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0answers
33 views

Plot3D is not working. Help [closed]

Plot3D[{x^(2)+4y^(2)+9z^(2)=1},{x,-5,5},{y,-5,5}] When I plot this it comes up as a plane which I know is incorrect, What is wrong?
0
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0answers
38 views

How would you plot the integral on [a,b] in terms of one variable x in mathematica?

How would you plot the definite integral ∫4 dx on interval [a,b] where a=0 and b=4 are the upper and lower bounds on mathemetmatica? The reason why I am asking is because I am practicing graphing ...
2
votes
1answer
76 views

3D Vectors wrap on the Sphere

How I can wrap the 3D vectors around the sphere surface like this one. My angles are ...
1
vote
3answers
76 views

Fittings of three equations

Can you help me to do the fit for the following equations to obtain the values of $a$ and $b$. {20.7 == a + b/(5^4), 28.62 == a + b/(6^4), 32.04 == a + b/(7^4)} ...
3
votes
0answers
40 views

neural network for a simple game?

I'm taking a class that is based on the Mathematica coding language, and we must do a 6-week final project. I am considering coding a neural network for a simple game like 2048, pacman, snake, etc. ...
6
votes
2answers
87 views

Removing duplicate rows and appending from a table of lists

For the table x with three lists per row: ...
-1
votes
1answer
39 views

Need help to find a value to linearize the data [closed]

I have a two column data which is y vs x. I want to linearize the data by this formula 1/(x-b) but I don't know how to determine the b value such that the ln(y) vs 1/(x-b) becomes a linear line. So I ...
2
votes
1answer
28 views

unbounded Voronoi iteration with finite and non-equal point radii

I would like to create a cool differential line growth animation based on this great tutorial. The only missing part is the relax node, but I couldn't find any pointers on the web how to implement ...
0
votes
0answers
49 views

Need help to fit an exponential function to the data

I have a problem with fitting an exponential function to the data. I used the NonlinearModelFit function to perform the fit. The code plots the fit but not the data and the standard error for the fit ...
0
votes
0answers
13 views

Type superscript at frame label

I have a frame to label as such: FrameLabel -> {{Style[Row[{"Ln(R)", " (a. u)"}], 18, "TR"], None}, {Style[Row[{"Inverse of T", " (K^-1)"}], 18, "TR"], None}} ...
2
votes
3answers
58 views

Solving ODE System and Estimating Parameters with Experimental Data

I am new to Mathematica. I am trying to find out the best-fit values of the parameters appearing in an ODE system of three equations. The three ODE equations are: ...
1
vote
1answer
34 views

Defining variables from an association list

I have list of rules, something like {f[x,y,z]-> F, g[x,y,z]-> G, D[f[x,y,z],x]-> fx,...} I would like to assign the values to the variables like I ...
0
votes
0answers
19 views

“not a quantified system of equations and inequalities” problem

I am trying to calculate a system of (almost) linear equations. I have 10 equations and 9 variables (first 10 lines in the Solve function), so it should be possible. ...
6
votes
2answers
521 views

All possible combinations of ways to write an equation

I want to define a function in Mathematica where I get all combinations of an expression, e.g., input: {q,p1,p2} Output: ...
0
votes
1answer
23 views

import and compare values in csv files according to a condition

I have lots of csv files in a folder. Each file contains a column with date, year and time and the second column values for each time. I would like to import all these files and for each file take a ...
2
votes
1answer
58 views

Computing the entropic risk measure symbolically in MMA

Using the link Definition, it is possible to compute the entropic risk measure as follows: $$ EVaR=\text{inf}_{z>0}\{z^{-1}\ln\left(\frac{M_X(z)}{\alpha}\right)\}, $$ wherein $X$ is a random ...
0
votes
2answers
47 views

Impulse response function h(t) of Gauss functions as a stimulus and response

From the basics of the signal theory the impulse response function (IRF) can be calculate like (L=Laplace transformation): L[x(t)]= X(s) , L[y(t)]= Y(s) and transfer function H(s)= Y(s)/X(s), then IRF ...
0
votes
1answer
46 views

plotting using evaluate [closed]

I have some simple equations such as ...
0
votes
0answers
32 views

How to save plots with opacity[0.5] with transparency?

How to save ParametricPlot with opacity[0.5] with transparency? When I save the image the transparency is completely lot. in both pdf and eps files. I use The following code for saving my parametric ...
0
votes
0answers
28 views

The code for arbitrary metric

While obtaining the Schwarzschild solution I want to evaluate the Christoffel symbols, Ricci tensor and etc by checking the results with Mathematica. Is there an online source to compute the wished ...

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