Items tagged with eigenvalues eigenvalues Tagged Items Feed

Hello,In short: I try to get the eigenvalues of a 16x16 complex matrix with one variable B__z. I know, the vales are very small (~10^-24), so I multiply with 10^24 and collect B__z. Now, when I use Eigenvalues(H) [H is the matrix] the result is just wrong:

test.mw

(same with original values) - compared to Mathematica which solves and plots in about 1 sec:

Where is the problem? What should I do? Any suggestions?

Hello,

first of all, this is my very fist question in this forum, so please excuse some formal mistakes I may make...

Using Maple 18.01 on Windows 7 64bit

To the topic: I want to calculate the eigenvalues of a complex matrix like this (just as an example):

M := Matrix(2, 2, {(1, 1) = a+2.5*I, (1, 2) = 1-I*a, (2, 1) = 4, (2, 2) = a})

When I try to calculate

Eigenvalues(M)

I get

Error, (in LinearAlgebra:-Eigenvalues) expecting either Matrices of rationals, rational functions, radical functions, algebraic numbers, or algebraic functions, or Matrices of complex(numeric) values

Strange, because if I replace the "2.5" with just "2", so an integer instead of a float, I get results:

I don't understand this strange behavior, since Mathematica i.e. calculates everything just fine...:

Thanks in advance for any suggestions.

Hi there

I have have a 18*18 matrix which almost each of its element are in symbolic form. Now I need to have all of its eigenvectors. Unfortunately when I use the "Eigenvalues()" function in maple i got nothing. In fact I got the error which comes below.

Error, (in content/polynom) general case of floats not handled

I need to know if there's a solution to eliminate the error? If not, what can I do to determine the eigenvectors and eigenvalues in symbolic form?

I'll be appreciated your help

Hello, everyone. I have some problem with multithreaded calculation. I just need calculate eigenvalues of matrix m at various parameters (and then export to a file) using advantages of the parallelizing. The following code works but in serial way

 

restart: with(LinearAlgebra):

m:=ImportMatrix(cat(currentdir(),"m.txt")): # here is matrix m.txt

step:=1:

 

prc:=proc(k1,k2)

local u,i,j,nmc:

u:=Matrix(ceil(1+(k2-k1)/step),5):

u[1,1]:=k1:

for i from 2 to op([1,1],u) do

u[i,1]:=u[i-1,1]+step:

end do:

for i from 1 to op([1,1],u) do

nmc:=sort(Eigenvalues(m*u[i,1], output='list')):

for j from 2 to op([1,2],u) do

u[i,j]:=nmc[j-1]:

end do:

writedata[APPEND](cat(currentdir(),"u_",convert(k2,string),".txt"), [convert(Re(u[i]),list)]):

print(u[i,1]);

end do:

return finished:

end proc:

 

with(Threads[Task]):

Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]);

quit:

 

The Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]) function makes two tasks of calculation at the parameter ranges of 1-20 and 21-40. But in this case Start spends twice more time than simply prc(20+step,40). How to realize a multithreaded calculation?

By the way I don't need to use a Concatenate function in Start but without any procedure Start doesn't work.

Aslam-u-Alikum... How are you? Hope you will be fine. I want to determine the eigenvalues of differential equation in Maple kindly help me... Problem.docx

Good day,

I try finding the eigen values of a 6 x 6 matrix with symbolic term but recieve the following error:

Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc

Please what do I do.

Thanks

Hello guys , i have a matrix that i want to find its eigenvalues , i have its answer but maple calculations didnt give its anwer.

answer:3(1+q),{-3m+sqrt(m*(256m^3+160m^2-31m-16)}/4m(m+1),{-3m-sqrt(m*(256m^3+160m^2-31m-16)}/43(m+1)

m and q can bu any number

maple calculation :

eigen.mw

 

 

 

thank you guys

Hi,

     I have a a matrix with one symbol and all others are numbers. I got this from doing 

   M := (1-x)*N + x*A :

 So my parameter is x, and N, A are numeric (real, symmetric) matricies. I want to plot the eigenvalues as x=0..1, but for a large matrix, say 25x25. Eigenvalues(M) only returns 17 eigenvalues, and more so, it doesnt keep them in the same order when plotting!

My issue is when Maple computes the...

how to find eigen value this 4x4 matrix:

Hello guys ,

I found critical points for a 3-D dynamical system (x,y,z) and m which in general is not constant (m(z/y) is a function of z.y, when i calculate eigenvalue for every critical point ,the maple assume m constant . how i find eigenvalues for general m which is not constant and is a function of z/y .

Thank You

ww.mw

Hi,

     For some reason Maple won't compute the eigenvalues to my matrix, which contains complex numbers and 1 symbolic parameter (h). heres the code

 

elements:=[1.+0.*I, -0.1e-5-0.4e-4*I, 0.2e-3+0.*I, -1.*10^(-7)-0.4e-5*I, -0.1e-5-0.4e-4*I, -0.1e-2+0.2e-4*I, -3.*10^(-7)+0.3e-4*I, -2.-0.2e-5*I, 0.3e-3+0.*I, -3.*10^(-7)+0.3e-4*I, 1.+0.*I, 6.*10^(-7)-0.2e-5*I, -1.*10^(-7)-0.4e-5*I, -2.-0.2e-5*I, 6.*10^(-7)-0.2e-5*I, -0.3e-4-9.*10^(-7)*I]:

Hello,

On a mechanical system that I could put in the classic form M*diff (x, t, 2) + K*x (t) = 0, I would like to calculate the angular frequencies.The methods that I know are:
- Calculate the solutions of the equation det (K-omega ^ 2 * M) = 0
- Or calculate the solutions of the equation det (M-1K-omega ^ 2 * I) = 0
- Or directly determine the eigenvalues ​​of M-1K using functions already created in Maple for example.

Hi,

I wonder if you could help me. I'm trying to calculate the eigenvalues of a complicated 3x3 matrix in Maple, but I'm not very familiar with Maple syntax. The answer maple has provided me with is in the form,

(&*(sin(pi*q/P),P/T,3x3 matrix))

How do I interpret this result? The eigenvalues are scalars.

Thanks for your help,

Sian

 

 

I intend to calculate the eigenvalues and eigenvectors, but for the same matrix when i executed the Eigenvectors command in mapple twice the eigenvalues generated are same both the times but the values of eigenvector are infinite at one instance whereas they are in numeric domain in the second instance.

Can anyone please tell me why this is occuring?

Hi,

 

I am working on a instability problem where I  pose my probkem as a generalized eigenvalue problem. My matrices can reach size 3000x3000. However, even this one 

with(RandomTools); with(LinearAlgebra);
interface(rtablesize = 20);

Digits := 25;
A := RandomMatrix(200, 200);
EigVal := evalf(Eigenvalues(A));

right now running for an hour but still no result. Is there a way to speed up this process? 

1 2 3 Page 1 of 3