slaed5.f - Man Page
SRC/slaed5.f
Synopsis
Functions/Subroutines
subroutine slaed5 (i, d, z, delta, rho, dlam)
SLAED5 used by SSTEDC. Solves the 2-by-2 secular equation.
Function/Subroutine Documentation
subroutine slaed5 (integer i, real, dimension( 2 ) d, real, dimension( 2 ) z, real, dimension( 2 ) delta, real rho, real dlam)
SLAED5 used by SSTEDC. Solves the 2-by-2 secular equation.
Purpose:
This subroutine 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.
- Parameters
I
I is INTEGER The index of the eigenvalue to be computed. I = 1 or I = 2.
D
D is REAL array, dimension (2) The original eigenvalues. We assume D(1) < D(2).
Z
Z is REAL array, dimension (2) The components of the updating vector.
DELTA
DELTA is REAL array, dimension (2) The vector DELTA contains the information necessary to construct the eigenvectors.
RHO
RHO is REAL The scalar in the symmetric updating formula.
DLAM
DLAM is REAL The computed lambda_I, the I-th updated eigenvalue.
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
- Contributors:
Ren-Cang Li, Computer Science Division, University of California at Berkeley, USA
Definition at line 107 of file slaed5.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page slaed5(3) is an alias of slaed5.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK