Visible to Intel only — GUID: GUID-3BFD8EB3-1701-4152-9D59-B7ABD7FC49CE
Visible to Intel only — GUID: GUID-3BFD8EB3-1701-4152-9D59-B7ABD7FC49CE
?laed5
Used by sstedc/dstedc. Solves the 2-by-2 secular equation.
Syntax
call slaed5( i, d, z, delta, rho, dlam )
call dlaed5( i, d, z, delta, rho, dlam )
Include Files
- mkl.fi
Description
The routine computes the i-th eigenvalue of a symmetric rank-one modification of a 2-by-2 diagonal matrix
diag(D) + rho*Z * transpose(Z).
The diagonal elements in the array D are assumed to satisfy
D(i) < D(j) for i < j.
We also assume rho > 0 and that the Euclidean norm of the vector Z is one.
Input Parameters
- i
-
INTEGER. The index of the eigenvalue to be computed;
1 ≤ i ≤ 2.
- d, z
-
REAL for slaed5
DOUBLE PRECISION for dlaed5
Arrays, dimension (2) each. The array d contains the original eigenvalues. It is assumed that d(1) < d(2).
The array z contains the components of the updating vector.
- rho
-
REAL for slaed5
DOUBLE PRECISION for dlaed5
The scalar in the symmetric updating formula.
Output Parameters
- delta
-
REAL for slaed5
DOUBLE PRECISION for dlaed5
Array, dimension (2).
The vector delta contains the information necessary to construct the eigenvectors.
- dlam
-
REAL for slaed5
DOUBLE PRECISION for dlaed5
The computed lambda_i, the i-th updated eigenvalue.