zscal Subroutine

public subroutine zscal(n, za, zx, incx)

NAME

zscal(3f) - [BLAS:COMPLEX16_BLAS_LEVEL1]

SYNOPSIS

 subroutine zscal(n,za,zx,incx)

   .. Scalar Arguments ..
   complex(kind=real64),intent(in)    :: za
   integer,intent(in)                 :: incx,n
   ..
   .. Array Arguments ..
   complex(kind=real64),intent(inout) :: zx(*)
   ..

DEFINITION

 ZSCAL scales a vector by a constant.

OPTIONS

N

       N is INTEGER
      number of elements in input vector(s)

ZA

       ZA is complex(kind=real64)
        On entry, ZA specifies the scalar alpha.

ZX

       ZX is complex(kind=real64) array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX

       INCX is INTEGER
      storage spacing between elements of ZX

AUTHORS

  • Univ. of Tennessee
  • Univ. of California Berkeley
  • Univ. of Colorado Denver
  • NAG Ltd.

date:November 2017

FURTHER DETAILS

  jack dongarra, 3/11/78.
  modified 3/93 to return if incx .le. 0.
  modified 12/3/93, array(1) declarations changed to array(*)

SEE ALSO

Online html documentation available at
http://www.netlib.org/lapack/explore-html/

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: n
complex(kind=real64), intent(in) :: za
complex(kind=real64), intent(inout) :: zx(*)
integer, intent(in) :: incx

Contents

Variables

Source Code

zscal

Variables

Type Visibility Attributes Name Initial
integer, public :: i
integer, public :: nincx

Source Code

       subroutine zscal(n,za,zx,incx)
      implicit none
!
!  -- Reference BLAS level1 routine (version 3.8.0) --
!  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
!  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
!     November 2017
!
!     .. Scalar Arguments ..
      complex(kind=real64),intent(in)    :: za
      integer,intent(in)                 :: incx,n
!     ..
!     .. Array Arguments ..
      complex(kind=real64),intent(inout) :: zx(*)
!     ..
!
!  =====================================================================
!
!     .. Local Scalars ..
      integer i,nincx
!     ..
      if (n.le.0 .or. incx.le.0) return
      if (incx.eq.1) then
!
!        code for increment equal to 1
!
         do i = 1,n
            zx(i) = za*zx(i)
         enddo
      else
!
!        code for increment not equal to 1
!
         nincx = n*incx
         do i = 1,nincx,incx
            zx(i) = za*zx(i)
         enddo
      endif

      end subroutine zscal