How can i correct this error ?

Hi

In my program, i use the function eig to return the eigenvalues :

[V,D]=eig(k,m);

But i have obtained this error:

Error using eig

EIG does not support generalized eigenproblem EIG(A,B) when A or B is sparse.

Please help me.

[Adam]

Clearly you need to give us more information on k and m. Judging from the error messages though it seems clear that one of your two inputs, k or m, are sparse matrices and these are not supported by Eig.

[Mallouli Marwa]

m=

   (1,1)                0.00075602592

   (3,1)                0.00013085064

   (4,1)              -8.00127432e-07

   (2,2)            1.25066072448e-08

   (3,2)               8.00127432e-07

   (4,2)            -4.6899777168e-09

   (1,3)                0.00013085064

   (2,3)               8.00127432e-07

   (3,3)                0.00037801296

   (4,3)             -1.354061808e-06

   (1,4)              -8.00127432e-07

   (2,4)            -4.6899777168e-09

   (3,4)             -1.354061808e-06

   (4,4)             6.2533036224e-09

And, k=

   (1,1)             28834278.0744617

   (3,1)            -14417139.0372308

   (4,1)             183097.665772832

   (2,2)             6200.90761417323

   (3,2)            -183097.665772832

   (4,2)             1550.22690354331

   (1,3)            -14417139.0372308

   (2,3)            -183097.665772832

   (3,3)             14417139.0372308

   (4,3)            -183097.665772832

   (1,4)             183097.665772832

   (2,4)             1550.22690354331

   (3,4)            -183097.665772832

   (4,4)             3100.45380708661

Answer 1

[Star Strider]

According to the sparse matrix section of the documentation, you need to use the eigs function.

[Mallouli Marwa]

Have they the same result ?

[Star Strider]

They seem to, but the results of eig are ordered opposite those of eigs. The eigs funciton works with sparse matrices, while eig does not.

Check them with something like this example (not using sparse matrix arguments):

A = randi([-9 9], 5);
[V1,D1] = eig(A)
[V2,D2] = eigs(A)