public interface lasd5
This subroutine computes the square root of the I-th eigenvalue
of a positive symmetric rank-one modification of a 2-by-2 diagonal
matrix
diag( D ) * diag( D ) + RHO * Z * transpose(Z) .
The diagonal entries in the array D are assumed to satisfy
0 <= D(i) < D(j) for i < j .
We also assume RHO > 0 and that the Euclidean norm of the vector
Z is one.
Subroutines
Arguments
| Type |
Intent | Optional | Attributes |
|
Name |
|
|
integer(kind=ilp),
|
intent(in) |
|
|
:: |
i |
|
|
real(kind=dp),
|
intent(in) |
|
|
:: |
d(2) |
|
|
real(kind=dp),
|
intent(in) |
|
|
:: |
z(2) |
|
|
real(kind=dp),
|
intent(out) |
|
|
:: |
delta(2) |
|
|
real(kind=dp),
|
intent(in) |
|
|
:: |
rho |
|
|
real(kind=dp),
|
intent(out) |
|
|
:: |
dsigma |
|
|
real(kind=dp),
|
intent(out) |
|
|
:: |
work(2) |
|
Arguments
| Type |
Intent | Optional | Attributes |
|
Name |
|
|
integer(kind=ilp),
|
intent(in) |
|
|
:: |
i |
|
|
real(kind=sp),
|
intent(in) |
|
|
:: |
d(2) |
|
|
real(kind=sp),
|
intent(in) |
|
|
:: |
z(2) |
|
|
real(kind=sp),
|
intent(out) |
|
|
:: |
delta(2) |
|
|
real(kind=sp),
|
intent(in) |
|
|
:: |
rho |
|
|
real(kind=sp),
|
intent(out) |
|
|
:: |
dsigma |
|
|
real(kind=sp),
|
intent(out) |
|
|
:: |
work(2) |
|
Module Procedures