Harry Garst

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16 years, 337 days

MaplePrimes Activity


These are questions asked by Harry Garst

The last months Maple 2020 suffers from frozen interface behavior:

I simply wanted to save a file, but that resulted in a frozen window:

After 10 minutes the file explorer window appeared, but also this screen is unresponsive.

I reinstalled Maple last month, but that didn't help. Remarkably, the problem comes and goes. It seems to me that some java problem is making my life difficult.
Any ideas?
kind regards,

Harry

 

ps I ran the process monitor of Sysinternals, but I have no idea if this has any relevance to the problems:

11460 RegOpenKey HKCR\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\PackageRepository\Extensions\windows.protocol\Maple.cwmaple.2020 NAME NOT FOUND Desired Access: Read

11460 ReqQueryValue HKCR\Maple.cwmaple.2020\URL Protocol NAME NOT FOUND Length: 12

11460 RegOpenKey HKCU\Software\Classes\Maple.cwmaple.2020  NAME NOT FOUND Desired Access: Maximum Allowed

I have been using Alex Potapchik & & Alec Mihailovs' procedure for generating a multivariate sample

https://www.mapleprimes.com/questions/37539-Generate-Data-From-A-Multivariate-Normal

How can I plot the eigenvectors in the 3D scatterplot?

``

restart

kernelopts(version); interface(version)

`Maple 2019.2, X86 64 WINDOWS, Nov 26 2019, Build ID 1435526`

 

`Standard Worksheet Interface, Maple 2019.2, Windows 10, November 26 2019 Build ID 1435526`

(1)

with(LinearAlgebra); with(Statistics); with(plots)

MultivariateNormalSample := proc (Sigma, V, N) local d; d := LinearAlgebra:-Dimension(V); LinearAlgebra:-LUDecomposition(Matrix(Sigma, datatype = float[8]), 'method' = 'Cholesky').ArrayTools:-Alias(Statistics:-Sample(Normal(0, 1), d*N), [d, N])+ArrayTools:-Replicate(Vector[column](V, datatype = float[8]), 1, N) end proc

Cov := Matrix([[4, 2.5, .4], [2.5, 2, .2], [.4, .2, .5]])

Cor := simplify(MatrixPower(DiagonalMatrix(Diagonal(Cov)), -1/2).Cov.MatrixPower(DiagonalMatrix(Diagonal(Cov)), -1/2))

S := MultivariateNormalSample(Cov, `<,>`(0, 0, 0), 1000); Statistics:-CovarianceMatrix(S^%T); map(Statistics:-Mean, [S[1], S[2]])

Determinant(Cov)

.795

(2)

Z := Scale(S^%T)

E, V := Eigenvectors(Cor)

E := Re(E); V := Re(V)

Vector(3, {(1) = 2.0005950859349144, (2) = .11194337607751015, (3) = .8874615374875758})

 

Matrix(%id = 18446746188592589870)

(3)

plots:-pointplot3d(Z, axes = normal, thickness = 1, symbol = circle, axis[1] = [color = black], axis[2] = [color = blue], axis[3] = [color = green], color = "DarkRed", orientation = [30, 75], viewpoint = "circleright", symbolsize = 1)

 

NULL

 

Download Plot_eigenvectors_in_3d_scatterplot.mw

I had expected that applying the power rule for exponents would lead to an answer of zero. Maple refuses to give the desired answer, but using a procedure it works as expected.

Did I miss something?
 

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restart

kernelopts(version)

`Maple 2019.2, X86 64 WINDOWS, Nov 26 2019, Build ID 1435526`

(1)

interface(version)

`Standard Worksheet Interface, Maple 2019.2, Windows 10, November 26 2019 Build ID 1435526`

(2)

simplify(exp(k*(ln(t)+ln(a)))-(exp(ln(t)+ln(a)))^k, symbolic)

exp(k*(ln(t)+ln(a)))-t^k*a^k

(3)

W := proc (m, n) local r; r := simplify(exp(m*n)-(exp(m))^n, symbolic); return r end proc

W(n, k)

0

(4)

subs(n = ln(t)+ln(a), W(n, k))

0

(5)

V := proc (m, n) local r; r := simplify((exp(m))^n, symbolic); return r end proc

V(n, k)

exp(k*n)

(6)

V(ln(t)+ln(a), k)

t^k*a^k

(7)

``


 

Download mapleprimes.mw

 

Did someone already made a Pointplot3d for a Principal Components Analysis with projections for some data points on the eigenvectors?

I like this example very much:

http://www.joyofdata.de/public/pca-3d/

but I want to add projections on the three eigenvectors for some data points. I think it has to do something with the dot product, but I do not know how to do it in Maple. 

Hopefully someone already did this and is willing to share it.

kind regards,

Harry

 

For a statistical course I will give next year, I would like to demonstrate the calculation of tetrachoric and polychoric correlations. Furthermore, it would be nice to show the students how the expectation-maximization algorithm works.

Has anyone already programmed this in Maple?

best regards,

Harry

 

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