la_lapack::lalsd Interface Reference

LALSD: uses the singular value decomposition of A to solve the least squares problem of finding X to minimize the Euclidean norm of each column of A*X-B, where A is N-by-N upper bidiagonal, and X and B are N-by-NRHS. The solution X overwrites B. The singular values of A smaller than RCOND times the largest singular value are treated as zero in solving the least squares problem; in this case a minimum norm solution is returned. The actual singular values are returned in D in ascending order. This code makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit in add/subtract, or on those binary machines without guard digits which subtract like the Cray XMP, Cray YMP, Cray C 90, or Cray 2. It could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none. More...

Public Member Functions
pure subroutine	clalsd (uplo, smlsiz, n, nrhs, d, e, b, ldb, rcond, rank, work, rwork, iwork, info)
	la_clalsd
pure subroutine	dlalsd (uplo, smlsiz, n, nrhs, d, e, b, ldb, rcond, rank, work, iwork, info)
	la_dlalsd
	la_qlalsd
pure subroutine	slalsd (uplo, smlsiz, n, nrhs, d, e, b, ldb, rcond, rank, work, iwork, info)
	la_slalsd
	la_wlalsd
pure subroutine	zlalsd (uplo, smlsiz, n, nrhs, d, e, b, ldb, rcond, rank, work, rwork, iwork, info)
	la_zlalsd

Detailed Description

LALSD: uses the singular value decomposition of A to solve the least squares problem of finding X to minimize the Euclidean norm of each column of A*X-B, where A is N-by-N upper bidiagonal, and X and B are N-by-NRHS. The solution X overwrites B. The singular values of A smaller than RCOND times the largest singular value are treated as zero in solving the least squares problem; in this case a minimum norm solution is returned. The actual singular values are returned in D in ascending order. This code makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit in add/subtract, or on those binary machines without guard digits which subtract like the Cray XMP, Cray YMP, Cray C 90, or Cray 2. It could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none.

Member Function/Subroutine Documentation

clalsd()

pure subroutine la_lapack::lalsd::clalsd	(	character, intent(in)	uplo,
		integer(ilp), intent(in)	smlsiz,
		integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	nrhs,
		real(sp), dimension(*), intent(inout)	d,
		real(sp), dimension(*), intent(inout)	e,
		complex(sp), dimension(ldb,*), intent(inout)	b,
		integer(ilp), intent(in)	ldb,
		real(sp), intent(in)	rcond,
		integer(ilp), intent(out)	rank,
		complex(sp), dimension(*), intent(out)	work,
		real(sp), dimension(*), intent(out)	rwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(out)	info
	)

dlalsd()

pure subroutine la_lapack::lalsd::dlalsd	(	character, intent(in)	uplo,
		integer(ilp), intent(in)	smlsiz,
		integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	nrhs,
		real(dp), dimension(*), intent(inout)	d,
		real(dp), dimension(*), intent(inout)	e,
		real(dp), dimension(ldb,*), intent(inout)	b,
		integer(ilp), intent(in)	ldb,
		real(dp), intent(in)	rcond,
		integer(ilp), intent(out)	rank,
		real(dp), dimension(*), intent(out)	work,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(out)	info
	)

la_clalsd()

la_lapack::lalsd::la_clalsd

la_dlalsd()

la_lapack::lalsd::la_dlalsd

la_qlalsd()

la_lapack::lalsd::la_qlalsd

la_slalsd()

la_lapack::lalsd::la_slalsd

la_wlalsd()

la_lapack::lalsd::la_wlalsd

la_zlalsd()

la_lapack::lalsd::la_zlalsd

slalsd()

pure subroutine la_lapack::lalsd::slalsd	(	character, intent(in)	uplo,
		integer(ilp), intent(in)	smlsiz,
		integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	nrhs,
		real(sp), dimension(*), intent(inout)	d,
		real(sp), dimension(*), intent(inout)	e,
		real(sp), dimension(ldb,*), intent(inout)	b,
		integer(ilp), intent(in)	ldb,
		real(sp), intent(in)	rcond,
		integer(ilp), intent(out)	rank,
		real(sp), dimension(*), intent(out)	work,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(out)	info
	)

zlalsd()

pure subroutine la_lapack::lalsd::zlalsd	(	character, intent(in)	uplo,
		integer(ilp), intent(in)	smlsiz,
		integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	nrhs,
		real(dp), dimension(*), intent(inout)	d,
		real(dp), dimension(*), intent(inout)	e,
		complex(dp), dimension(ldb,*), intent(inout)	b,
		integer(ilp), intent(in)	ldb,
		real(dp), intent(in)	rcond,
		integer(ilp), intent(out)	rank,
		complex(dp), dimension(*), intent(out)	work,
		real(dp), dimension(*), intent(out)	rwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(out)	info
	)

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The documentation for this interface was generated from the following file:

• la_lapack.f90