Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3 - computes the eigenvalues of a 2-by-2 symmetric matrix  [ A B ]  [ B C ]

SYNOPSIS

       SUBROUTINE SLAE2( A, B, C, RT1, RT2 )

           REAL          A, B, C, RT1, RT2

PURPOSE

       SLAE2  computes the eigenvalues of a 2-by-2 symmetric matrix
          [  A   B  ]
          [  B   C  ].
        On return, RT1 is the eigenvalue of larger absolute value, and RT2
        is the eigenvalue of smaller absolute value.

ARGUMENTS

        A       (input) REAL
                The (1,1) element of the 2-by-2 matrix.

        B       (input) REAL
                The (1,2) and (2,1) elements of the 2-by-2 matrix.

        C       (input) REAL
                The (2,2) element of the 2-by-2 matrix.

        RT1     (output) REAL
                The eigenvalue of larger absolute value.

        RT2     (output) REAL
                The eigenvalue of smaller absolute value.

FURTHER DETAILS

        RT1 is accurate to a few ulps barring over/underflow.
        RT2 may be inaccurate if there is massive cancellation in the
        determinant A*C-B*B; higher precision or correctly rounded or
        correctly truncated arithmetic would be needed to compute RT2
        accurately in all cases.
        Overflow is possible only if RT1 is within a factor of 5 of overflow.
        Underflow is harmless if the input data is 0 or exceeds
           underflow_threshold / macheps.

 LAPACK auxiliary routine (version 3.2)     April 2011                             SLAE2(3lapack)