orbdb2 Interface

public interface orbdb2

ORBDB2 simultaneously bidiagonalizes the blocks of a tall and skinny matrix X with orthonomal columns: [ B11 ] [ X11 ] [ P1 | ] [ 0 ] [-----] = [---------] [-----] Q1**T . [ X21 ] [ | P2 ] [ B21 ] [ 0 ] X11 is P-by-Q, and X21 is (M-P)-by-Q. P must be no larger than M-P, Q, or M-Q. Routines DORBDB1, DORBDB3, and DORBDB4 handle cases in which P is not the minimum dimension. The orthogonal matrices P1, P2, and Q1 are P-by-P, (M-P)-by-(M-P), and (M-Q)-by-(M-Q), respectively. They are represented implicitly by Householder vectors. B11 and B12 are P-by-P bidiagonal matrices represented implicitly by angles THETA, PHI.


Subroutines

public subroutine dorbdb2(m, p, q, x11, ldx11, x21, ldx21, theta, phi, taup1, taup2, tauq1, work, lwork, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: p
integer(kind=ilp), intent(in) :: q
real(kind=dp), intent(inout) :: x11(ldx11,*)
integer(kind=ilp), intent(in) :: ldx11
real(kind=dp), intent(inout) :: x21(ldx21,*)
integer(kind=ilp), intent(in) :: ldx21
real(kind=dp), intent(out) :: theta(*)
real(kind=dp), intent(out) :: phi(*)
real(kind=dp), intent(out) :: taup1(*)
real(kind=dp), intent(out) :: taup2(*)
real(kind=dp), intent(out) :: tauq1(*)
real(kind=dp), intent(out) :: work(*)
integer(kind=ilp), intent(in) :: lwork
integer(kind=ilp), intent(out) :: info

public subroutine sorbdb2(m, p, q, x11, ldx11, x21, ldx21, theta, phi, taup1, taup2, tauq1, work, lwork, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: p
integer(kind=ilp), intent(in) :: q
real(kind=sp), intent(inout) :: x11(ldx11,*)
integer(kind=ilp), intent(in) :: ldx11
real(kind=sp), intent(inout) :: x21(ldx21,*)
integer(kind=ilp), intent(in) :: ldx21
real(kind=sp), intent(out) :: theta(*)
real(kind=sp), intent(out) :: phi(*)
real(kind=sp), intent(out) :: taup1(*)
real(kind=sp), intent(out) :: taup2(*)
real(kind=sp), intent(out) :: tauq1(*)
real(kind=sp), intent(out) :: work(*)
integer(kind=ilp), intent(in) :: lwork
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_dorbdb2()

Arguments

None

public interface stdlib_sorbdb2()

Arguments

None