SymmetricMatrixEigenvalues Method

public double[] Eigenvalues()

Public Function Eigenvalues As Double()

public:
array<double>^ Eigenvalues()

member Eigenvalues : unit -> float[] 

Return Value

If you require only the eigenvalues of the matrix, not its eigenvectors, this method will return them faster than the Eigendecomposition method. If you do need the eigenvectors as well as the eigenvalues, use the Eigendecomposition method instead.

Reference