fortran-lapack

fortran-lapack copied to clipboard

I think stdlib_scsum1 in stdlib_linalg_lapack_s.f90 can be rewritten without gotos as

     pure real(sp) function stdlib_scsum1(n,cx,incx)
        ! -- lapack auxiliary routine --
        ! -- lapack is a software package provided by univ. of tennessee,    --
        ! -- univ. of california berkeley, univ. of colorado denver and nag ltd..--
           ! Scalar Arguments
           integer(ilp),intent(in) :: incx,n
           ! Array Arguments
           complex(sp),intent(in) :: cx(*)
        ! =====================================================================
           ! Local Scalars
           integer(ilp) :: i,nincx
           real(sp) :: stemp
           ! Intrinsic Functions
           intrinsic :: abs
           ! Executable Statements
           stdlib_scsum1 = zero
           stemp = zero
           if (n <= 0) return
           if (incx /= 1) then
               ! code for increment not equal to 1
               nincx = n*incx
               do i = 1,nincx,incx
                  ! next line modified.
                  stemp = stemp + abs(cx(i))
               end do
               stdlib_scsum1 = stemp
           else
               ! code for increment equal to 1
               do i = 1,n
                  ! next line modified.
                  stemp = stemp + abs(cx(i))
               end do
               stdlib_scsum1 = stemp
           end if
           return
     end function stdlib_scsum1

The original is

     pure real(sp) function stdlib_scsum1(n,cx,incx)
        ! -- lapack auxiliary routine --
        ! -- lapack is a software package provided by univ. of tennessee,    --
        ! -- univ. of california berkeley, univ. of colorado denver and nag ltd..--
           ! Scalar Arguments
           integer(ilp),intent(in) :: incx,n
           ! Array Arguments
           complex(sp),intent(in) :: cx(*)
        ! =====================================================================
           ! Local Scalars
           integer(ilp) :: i,nincx
           real(sp) :: stemp
           ! Intrinsic Functions
           intrinsic :: abs
           ! Executable Statements
           stdlib_scsum1 = zero
           stemp = zero
           if (n <= 0) return
           if (incx == 1) go to 20
           ! code for increment not equal to 1
           nincx = n*incx
           do i = 1,nincx,incx
              ! next line modified.
              stemp = stemp + abs(cx(i))
           end do
           stdlib_scsum1 = stemp
           return
           ! code for increment equal to 1
           20 continue
           do i = 1,n
              ! next line modified.
              stemp = stemp + abs(cx(i))
           end do
           stdlib_scsum1 = stemp
           return
     end function stdlib_scsum1

A general question is whether doing the work to eliminate as many gotos as possible is worth it. If it has to be done manually, perhaps not.