orbdb1 Interface

public interface orbdb1

ORBDB1 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. Q must be no larger than P, M-P, or M-Q. Routines DORBDB2, DORBDB3, and DORBDB4 handle cases in which Q 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 Q-by-Q bidiagonal matrices represented implicitly by angles THETA, PHI.


Subroutines

public subroutine dorbdb1(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 sorbdb1(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_dorbdb1()

Arguments

None

public interface stdlib_sorbdb1()

Arguments

None