module mathconsts
!----- LGPL --------------------------------------------------------------------
!                                                                               
!  Copyright (C)  Stichting Deltares, 2011-2014.                                
!                                                                               
!  This library is free software; you can redistribute it and/or                
!  modify it under the terms of the GNU Lesser General Public                   
!  License as published by the Free Software Foundation version 2.1.                 
!                                                                               
!  This library 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            
!  Lesser General Public License for more details.                              
!                                                                               
!  You should have received a copy of the GNU Lesser General Public             
!  License along with this library; if not, see <http://www.gnu.org/licenses/>. 
!                                                                               
!  contact: delft3d.support@deltares.nl                                         
!  Stichting Deltares                                                           
!  P.O. Box 177                                                                 
!  2600 MH Delft, The Netherlands                                               
!                                                                               
!  All indications and logos of, and references to, "Delft3D" and "Deltares"    
!  are registered trademarks of Stichting Deltares, and remain the property of  
!  Stichting Deltares. All rights reserved.                                     
!                                                                               
!-------------------------------------------------------------------------------
!  $Id$
!  $HeadURL$
!!--description-----------------------------------------------------------------
!
! This module defines some general mathematical constants like pi and
! conversion factors from degrees to radians and from (earth) days to
! seconds.
!
! This module does NOT include physical constants like earth radius and
! gravity, or application dependent constants like missing values.
!
!!--pseudo code and references--------------------------------------------------
! NONE
!!--declarations----------------------------------------------------------------
   use precision
   implicit none
   
   !
   ! flexible precision constants
   !
   real(fp), save :: pi     = 4.0_fp*atan(1.0_fp)          !< pi = 3.141592...
   real(fp), save :: degrad = 4.0_fp*atan(1.0_fp)/180.0_fp !< conversion factor from degrees to radians  
   real(fp), save :: raddeg = 180.0_fp/4.0_fp*atan(1.0_fp) !< conversion factor from radians to degrees
   real(fp), save :: daysec = 24.0_fp*60.0_fp*60.0_fp      !< conversion factor from earth day to seconds
   real(fp), save :: eps_fp = epsilon(1.0_fp)              !< epsilon for fp
   
   !
   ! high precision constants
   !
   real(hp), save :: pi_hp      = 4.0_hp*atan(1.0_hp)          !< pi = 3.14159265358979...
   real(hp), save :: degrad_hp  = 4.0_hp*atan(1.0_hp)/180.0_hp !< conversion factor from degrees to radians
   real(hp), save :: raddeg_hp  = 180.0_hp/4.0_hp*atan(1.0_hp) !< conversion factor from radians to degrees
   real(hp), save :: daysec_hp  = 24.0_hp*60.0_hp*60.0_hp      !< conversion factor from earth day to seconds
   real(hp), save :: yearsec_hp = 31536000.0_hp                !< conversion factor from earth year to seconds
   real(hp), save :: eps_hp     = epsilon(1.0_hp)              !< epsilon for hp
   
   contains
      
      !> Obsolete initialization method.
      subroutine init_mathconsts()
          !
      end subroutine init_mathconsts
      
end module mathconsts