la_lapack::poequb Interface Reference

POEQUB: computes row and column scalings intended to equilibrate a Hermitian positive definite matrix A and reduce its condition number (with respect to the two-norm). S contains the scale factors, S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This choice of S puts the condition number of B within a factor N of the smallest possible condition number over all possible diagonal scalings. This routine differs from CPOEQU by restricting the scaling factors to a power of the radix. Barring over- and underflow, scaling by these factors introduces no additional rounding errors. However, the scaled diagonal entries are no longer approximately 1 but lie between sqrt(radix) and 1/sqrt(radix). More...

Public Member Functions
pure subroutine	cpoequb (n, a, lda, s, scond, amax, info)
	la_cpoequb
pure subroutine	dpoequb (n, a, lda, s, scond, amax, info)
	la_dpoequb
	la_qpoequb
pure subroutine	spoequb (n, a, lda, s, scond, amax, info)
	la_spoequb
	la_wpoequb
pure subroutine	zpoequb (n, a, lda, s, scond, amax, info)
	la_zpoequb

Detailed Description

POEQUB: computes row and column scalings intended to equilibrate a Hermitian positive definite matrix A and reduce its condition number (with respect to the two-norm). S contains the scale factors, S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This choice of S puts the condition number of B within a factor N of the smallest possible condition number over all possible diagonal scalings. This routine differs from CPOEQU by restricting the scaling factors to a power of the radix. Barring over- and underflow, scaling by these factors introduces no additional rounding errors. However, the scaled diagonal entries are no longer approximately 1 but lie between sqrt(radix) and 1/sqrt(radix).

Member Function/Subroutine Documentation

cpoequb()

pure subroutine la_lapack::poequb::cpoequb	(	integer(ilp), intent(in)	n,
		complex(sp), dimension(lda,*), intent(in)	a,
		integer(ilp), intent(in)	lda,
		real(sp), dimension(*), intent(out)	s,
		real(sp), intent(out)	scond,
		real(sp), intent(out)	amax,
		integer(ilp), intent(out)	info
	)

dpoequb()

pure subroutine la_lapack::poequb::dpoequb	(	integer(ilp), intent(in)	n,
		real(dp), dimension(lda,*), intent(in)	a,
		integer(ilp), intent(in)	lda,
		real(dp), dimension(*), intent(out)	s,
		real(dp), intent(out)	scond,
		real(dp), intent(out)	amax,
		integer(ilp), intent(out)	info
	)

la_cpoequb()

la_lapack::poequb::la_cpoequb

la_dpoequb()

la_lapack::poequb::la_dpoequb

la_qpoequb()

la_lapack::poequb::la_qpoequb

la_spoequb()

la_lapack::poequb::la_spoequb

la_wpoequb()

la_lapack::poequb::la_wpoequb

la_zpoequb()

la_lapack::poequb::la_zpoequb

spoequb()

pure subroutine la_lapack::poequb::spoequb	(	integer(ilp), intent(in)	n,
		real(sp), dimension(lda,*), intent(in)	a,
		integer(ilp), intent(in)	lda,
		real(sp), dimension(*), intent(out)	s,
		real(sp), intent(out)	scond,
		real(sp), intent(out)	amax,
		integer(ilp), intent(out)	info
	)

zpoequb()

pure subroutine la_lapack::poequb::zpoequb	(	integer(ilp), intent(in)	n,
		complex(dp), dimension(lda,*), intent(in)	a,
		integer(ilp), intent(in)	lda,
		real(dp), dimension(*), intent(out)	s,
		real(dp), intent(out)	scond,
		real(dp), intent(out)	amax,
		integer(ilp), intent(out)	info
	)

---

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

• la_lapack.f90