pbequ Interface

public interface pbequ

PBEQU computes row and column scalings intended to equilibrate a Hermitian positive definite band 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.


Subroutines

public pure subroutine cpbequ(uplo, n, kd, ab, ldab, s, scond, amax, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: kd
complex(kind=sp), intent(in) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
real(kind=sp), intent(out) :: s(*)
real(kind=sp), intent(out) :: scond
real(kind=sp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine dpbequ(uplo, n, kd, ab, ldab, s, scond, amax, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: kd
real(kind=dp), intent(in) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
real(kind=dp), intent(out) :: s(*)
real(kind=dp), intent(out) :: scond
real(kind=dp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine spbequ(uplo, n, kd, ab, ldab, s, scond, amax, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: kd
real(kind=sp), intent(in) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
real(kind=sp), intent(out) :: s(*)
real(kind=sp), intent(out) :: scond
real(kind=sp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine zpbequ(uplo, n, kd, ab, ldab, s, scond, amax, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: kd
complex(kind=dp), intent(in) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
real(kind=dp), intent(out) :: s(*)
real(kind=dp), intent(out) :: scond
real(kind=dp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_cpbequ()

Arguments

None

public interface stdlib_dpbequ()

Arguments

None

public interface stdlib_spbequ()

Arguments

None

public interface stdlib_zpbequ()

Arguments

None