laexc Interface

public interface laexc

LAEXC swaps adjacent diagonal blocks T11 and T22 of order 1 or 2 in an upper quasi-triangular matrix T by an orthogonal similarity transformation. T must be in Schur canonical form, that is, block upper triangular with 1-by-1 and 2-by-2 diagonal blocks; each 2-by-2 diagonal block has its diagonal elements equal and its off-diagonal elements of opposite sign.


Subroutines

public subroutine dlaexc(wantq, n, t, ldt, q, ldq, j1, n1, n2, work, info)

Arguments

Type IntentOptional Attributes Name
logical(kind=lk), intent(in) :: wantq
integer(kind=ilp), intent(in) :: n
real(kind=dp), intent(inout) :: t(ldt,*)
integer(kind=ilp), intent(in) :: ldt
real(kind=dp), intent(inout) :: q(ldq,*)
integer(kind=ilp), intent(in) :: ldq
integer(kind=ilp), intent(in) :: j1
integer(kind=ilp), intent(in) :: n1
integer(kind=ilp), intent(in) :: n2
real(kind=dp), intent(out) :: work(*)
integer(kind=ilp), intent(out) :: info

public subroutine slaexc(wantq, n, t, ldt, q, ldq, j1, n1, n2, work, info)

Arguments

Type IntentOptional Attributes Name
logical(kind=lk), intent(in) :: wantq
integer(kind=ilp), intent(in) :: n
real(kind=sp), intent(inout) :: t(ldt,*)
integer(kind=ilp), intent(in) :: ldt
real(kind=sp), intent(inout) :: q(ldq,*)
integer(kind=ilp), intent(in) :: ldq
integer(kind=ilp), intent(in) :: j1
integer(kind=ilp), intent(in) :: n1
integer(kind=ilp), intent(in) :: n2
real(kind=sp), intent(out) :: work(*)
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_dlaexc()

Arguments

None

public interface stdlib_slaexc()

Arguments

None