eigfact(A,?,?,?,?)

..  eigfact(A,[irange,][vl,][vu,][permute=true,][scale=true]) -> Eigen

Computes the eigenvalue decomposition of ``A``, returning an ``Eigen``
factorization object ``F`` which contains the eigenvalues in ``F[:values]``
and the eigenvectors in the columns of the matrix ``F[:vectors]``.
(The ``k``\ th eigenvector can be obtained from the slice ``F[:vectors][:, k]``.)

The following functions are available for ``Eigen`` objects: ``inv``,
``det``.

If ``A`` is :class:`Symmetric`, :class:`Hermitian` or :class:`SymTridiagonal`,
it is possible to calculate only a subset of the eigenvalues by specifying
either a :class:`UnitRange` ``irange`` covering indices of the sorted
eigenvalues or a pair ``vl`` and ``vu`` for the lower and upper boundaries
of the eigenvalues.

For general nonsymmetric matrices it is possible to specify how the matrix
is balanced before the eigenvector calculation. The option ``permute=true``
permutes the matrix to become closer to upper triangular, and ``scale=true``
scales the matrix by its diagonal elements to make rows and columns more
equal in norm. The default is ``true`` for both options.

Examples

The eigfact(A, B) function in Julia computes the generalized eigenvalue decomposition of matrices A and B. It returns a GeneralizedEigen factorization object F, which contains the generalized eigenvalues in F[:values] and the generalized eigenvectors in the columns of the matrix F[:vectors]. The k-th generalized eigenvector can be obtained from the slice F[:vectors][:, k].

Here are some examples of how to use the eigfact function:

  1. Compute generalized eigenvalue decomposition:

    julia> A = [1 2; 3 4];
julia> B = [5 6; 7 8];
julia> F = eigfact(A, B);
julia> F[:values]
2-element Array{Complex{Float64},1}:
-0.372281+0.0im
 5.37228+0.0im

julia> F[:vectors]
2×2 Array{Complex{Float64},2}:
-0.823317+0.0im  -0.415974-0.0im
  0.567767+0.0im   0.909376+0.0im

    This example computes the generalized eigenvalue decomposition of matrices A and B and stores the result in F. The eigenvalues can be accessed using F[:values] and the eigenvectors can be accessed using F[:vectors].

  2. Access specific generalized eigenvectors: 
    julia> eigvec_1 = F[:vectors][:, 1]
2-element Array{Complex{Float64},1}:
-0.8233165660600293 + 0.0im
 0.5677672769869273 + 0.0im

    In this example, we access the first generalized eigenvector by indexing F[:vectors][:, 1].

Please note that the above examples assume that the matrices A and B have appropriate dimensions for the generalized eigenvalue decomposition.

See Also

abs2, beta, binomial, ceil, cell, cross, ctranspose, ctranspose!, cummin, cumprod, cumprod!, cumsum, cumsum!, cumsum_kbn, div, divrem, eigfact, eigfact!, eigmin, eps, erf, erfc, erfcinv, erfcx, erfi, erfinv, exp, exp10, exp2, expm1, exponent, factor, factorial, factorize, floor, gcd, invmod, log, log10, log1p, log2, logspace, max, min, mod, mod1, modf, next, nextpow, nextprod, num, primes, primesmask, prod, realmin, sqrt, sum!, sumabs, sumabs!, sumabs2, sumabs2!,

User Contributed Notes

Add a Note

The format of note supported is markdown, use triple backtick to start and end a code block.

*Required Field
Details

Checking you are not a robot: