ppequ Interface

public interface ppequ

PPEQU computes row and column scalings intended to equilibrate a Hermitian positive definite matrix A in packed storage 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 cppequ(uplo, n, ap, s, scond, amax, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
complex(kind=sp), intent(in) :: ap(*)
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 dppequ(uplo, n, ap, s, scond, amax, info)

Arguments

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

Arguments

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

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
complex(kind=dp), intent(in) :: ap(*)
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_cppequ()

Arguments

None

public interface stdlib_dppequ()

Arguments

None

public interface stdlib_sppequ()

Arguments

None

public interface stdlib_zppequ()

Arguments

None