la_syamv Interface

public interface la_syamv

LA_SYAMV performs the matrix-vector operation y := alphaabs(A)abs(x) + beta*abs(y), where alpha and beta are scalars, x and y are vectors and A is an n by n symmetric matrix. This function is primarily used in calculating error bounds. To protect against underflow during evaluation, components in the resulting vector are perturbed away from zero by (N+1) times the underflow threshold. To prevent unnecessarily large errors for block-structure embedded in general matrices, "symbolically" zero components are not perturbed. A zero entry is considered "symbolic" if all multiplications involved in computing that entry have at least one zero multiplicand.


Subroutines

public subroutine cla_syamv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
real(kind=sp), intent(in) :: alpha
complex(kind=sp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
complex(kind=sp), intent(in) :: x(*)
integer(kind=ilp), intent(in) :: incx
real(kind=sp), intent(in) :: beta
real(kind=sp), intent(inout) :: y(*)
integer(kind=ilp), intent(in) :: incy

public subroutine dla_syamv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
real(kind=dp), intent(in) :: alpha
real(kind=dp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=dp), intent(in) :: x(*)
integer(kind=ilp), intent(in) :: incx
real(kind=dp), intent(in) :: beta
real(kind=dp), intent(inout) :: y(*)
integer(kind=ilp), intent(in) :: incy

public subroutine sla_syamv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
real(kind=sp), intent(in) :: alpha
real(kind=sp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
real(kind=sp), intent(in) :: x(*)
integer(kind=ilp), intent(in) :: incx
real(kind=sp), intent(in) :: beta
real(kind=sp), intent(inout) :: y(*)
integer(kind=ilp), intent(in) :: incy

public subroutine zla_syamv(uplo, n, alpha, a, lda, x, incx, beta, y, incy)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
real(kind=dp), intent(in) :: alpha
complex(kind=dp), intent(in) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
complex(kind=dp), intent(in) :: x(*)
integer(kind=ilp), intent(in) :: incx
real(kind=dp), intent(in) :: beta
real(kind=dp), intent(inout) :: y(*)
integer(kind=ilp), intent(in) :: incy

Module Procedures

public interface stdlib_cla_syamv()

Arguments

None

public interface stdlib_dla_syamv()

Arguments

None

public interface stdlib_sla_syamv()

Arguments

None

public interface stdlib_zla_syamv()

Arguments

None