geequb Interface

public interface geequb

GEEQUB computes row and column scalings intended to equilibrate an M-by-N matrix A and reduce its condition number. R returns the row scale factors and C the column scale factors, chosen to try to make the largest element in each row and column of the matrix B with elements B(i,j)=R(i)A(i,j)C(j) have an absolute value of at most the radix. R(i) and C(j) are restricted to be a power of the radix between SMLNUM = smallest safe number and BIGNUM = largest safe number. Use of these scaling factors is not guaranteed to reduce the condition number of A but works well in practice. This routine differs from CGEEQU 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 entries' magnitudes are no longer approximately 1 but lie between sqrt(radix) and 1/sqrt(radix).


Subroutines

public pure subroutine cgeequb(m, n, a, lda, r, c, rowcnd, colcnd, amax, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: n
complex(kind=sp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=sp), intent(out) :: r(*)
real(kind=sp), intent(out) :: c(*)
real(kind=sp), intent(out) :: rowcnd
real(kind=sp), intent(out) :: colcnd
real(kind=sp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine dgeequb(m, n, a, lda, r, c, rowcnd, colcnd, amax, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: n
real(kind=dp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=dp), intent(out) :: r(*)
real(kind=dp), intent(out) :: c(*)
real(kind=dp), intent(out) :: rowcnd
real(kind=dp), intent(out) :: colcnd
real(kind=dp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine sgeequb(m, n, a, lda, r, c, rowcnd, colcnd, amax, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: n
real(kind=sp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=sp), intent(out) :: r(*)
real(kind=sp), intent(out) :: c(*)
real(kind=sp), intent(out) :: rowcnd
real(kind=sp), intent(out) :: colcnd
real(kind=sp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

public pure subroutine zgeequb(m, n, a, lda, r, c, rowcnd, colcnd, amax, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: m
integer(kind=ilp), intent(in) :: n
complex(kind=dp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=dp), intent(out) :: r(*)
real(kind=dp), intent(out) :: c(*)
real(kind=dp), intent(out) :: rowcnd
real(kind=dp), intent(out) :: colcnd
real(kind=dp), intent(out) :: amax
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_cgeequb()

Arguments

None

public interface stdlib_dgeequb()

Arguments

None

public interface stdlib_sgeequb()

Arguments

None

public interface stdlib_zgeequb()

Arguments

None