实对称正定矩阵LDL^分解，其中L为单位下三角矩阵，D为对角阵-A recursive algorithm for calculating the eigenvalues of a real symmetric matrix based on LDLT decomposition is given.

With this algorithm, the number of eigenvalues of a real symmetric matrix in the given interval can be counted, and the eigenvalues

of the matrix can be calculated.Through theoretical analysis and numerical simulation, this algorithm is proved to be effective.