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!**********************************************************************
! Copyright 1998,1999,2000,2001,2002,2005,2007,2008,2009,2010 *
! Andreas Stohl, Petra Seibert, A. Frank, Gerhard Wotawa, *
! Caroline Forster, Sabine Eckhardt, John Burkhart, Harald Sodemann *
! *
! This file is part of FLEXPART. *
! *
! FLEXPART is free software: you can redistribute it and/or modify *
! it under the terms of the GNU General Public License as published by*
! the Free Software Foundation, either version 3 of the License, or *
! (at your option) any later version. *
! *
! FLEXPART is distributed in the hope that it will be useful, *
! but WITHOUT ANY WARRANTY; without even the implied warranty of *
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
! GNU General Public License for more details. *
! *
! You should have received a copy of the GNU General Public License *
! along with FLEXPART. If not, see <http://www.gnu.org/licenses/>. *
!**********************************************************************
subroutine mean(x,xm,xs,number)
!*****************************************************************************
! *
! This subroutine calculates mean and standard deviation of a given element.*
! *
! AUTHOR: Andreas Stohl, 25 January 1994 *
! *
!*****************************************************************************
! *
! Variables: *
! x(number) field of input data *
! xm mean *
! xs standard deviation *
! number number of elements of field x *
! *
! Constants: *
! eps tiny number *
! *
!*****************************************************************************
implicit none
integer :: number,i
real :: x(number),xm,xs,xl,xq,xaux
real,parameter :: eps=1.0e-30
xl=0.
xq=0.
do i=1,number
xl=xl+x(i)
xq=xq+x(i)*x(i)
end do
xm=xl/real(number)
xaux=xq-xl*xl/real(number)
if (xaux.lt.eps) then
xs=0.
else
xs=sqrt(xaux/real(number-1))
endif
end subroutine mean
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