minresqlpblasmodule Module Reference

Functions/Subroutines
real(dp) function, public	ddot (n, dx, incx, dy, incy)
	DDOT forms the dot product of two vectors.
real(dp) function, public	dnrm2 (n, x, incx)
	DNRM2 returns the euclidean norm of a vector.

Function/Subroutine Documentation

ddot()

real(dp) function, public minresqlpblasmodule::ddot	(	integer(ip), intent(in)	n,
		real(dp), dimension(*), intent(in)	dx,
		integer(ip), intent(in)	incx,
		real(dp), dimension(*), intent(in)	dy,
		integer(ip), intent(in)	incy
	)

DDOT forms the dot product of two vectors.

Definition at line 87 of file minresqlpBlasModule.f90.

 
      implicit none
      integer(ip), intent(in) :: n,incx,incy
      real(dp),    intent(in) :: dx(*),dy(*)
 
      real(dp)    :: dtemp
      integer(ip) :: i,ix,iy,m
 
      ddot  = zero
      dtemp = zero
      if ( n <= 0 ) then
         return
      end if
 
!  Code for unequal increments or equal increments
!  not equal to 1.
 
      if ( incx /= 1 .or. incy /= 1 ) then
 
         if ( 0 <= incx ) then
            ix = 1
         else
            ix = ( - n + 1 ) * incx + 1
         end if
 
         if ( 0 <= incy ) then
            iy = 1
         else
            iy = ( - n + 1 ) * incy + 1
         end if
 
         do i = 1, n
            dtemp = dtemp + dx(ix) * dy(iy)
            ix = ix + incx
            iy = iy + incy
         end do
 
!  Code for both increments equal to 1.
 
        else
 
           m = mod( n, 5 )
 
           do i = 1, m
              dtemp = dtemp + dx(i) * dy(i)
           end do
 
           do i = m+1, n, 5
              dtemp = dtemp + dx(i)*dy(i) + dx(i+1)*dy(i+1) + dx(i+2)*dy(i+2) &
                                          + dx(i+3)*dy(i+3) + dx(i+4)*dy(i+4)
           end do
 
        end if
 
        ddot = dtemp
        return

dnrm2()

real(dp) function, public minresqlpblasmodule::dnrm2	(	integer(ip), intent(in)	n,
		real(dp), dimension(*), intent(in)	x,
		integer(ip), intent(in)	incx
	)

DNRM2 returns the euclidean norm of a vector.

Definition at line 184 of file minresqlpBlasModule.f90.

 
      implicit none
      integer(ip), intent(in) :: n,incx
      real(dp),    intent(in) :: x(*)
 
      integer(ip) :: ix
      real(dp)    :: ssq,absxi,norm,scale
 
      if ( n < 1 .or. incx < 1 ) then
         norm  = zero
      else if ( n == 1 ) then
         norm  = abs( x(1) )
      else
         scale = zero
         ssq   = one
 
         do ix = 1, 1 + ( n - 1 )*incx, incx
            if ( x(ix) /= zero ) then
               absxi = abs( x(ix) )
               if ( scale < absxi ) then
                  ssq = 1_dp + ssq * ( scale / absxi )**2
                  scale = absxi
               else
                  ssq = ssq + ( absxi / scale )**2
               end if
            end if
         end do
         norm  = scale * sqrt( ssq )
      end if
 
      dnrm2 = norm
      return