1!
2! Copyright (C) 2002-2006 Quantum ESPRESSO group
3! This file is distributed under the terms of the
4! GNU General Public License. See the file `License'
5! in the root directory of the present distribution,
6! or http://www.gnu.org/copyleft/gpl.txt .
7!
8!----------------------------------------------------------------------------
9MODULE upf_const
10  !----------------------------------------------------------------------------
11  !
12  USE upf_kinds, ONLY : DP
13  !
14  ! ... The constants needed everywhere
15  !
16  IMPLICIT NONE
17  !
18  SAVE
19  !
20  ! ... Mathematical constants
21  !
22  REAL(DP), PARAMETER :: pi     = 3.14159265358979323846_DP
23  REAL(DP), PARAMETER :: tpi    = 2.0_DP * pi
24  REAL(DP), PARAMETER :: fpi    = 4.0_DP * pi
25  !
26  ! ... zero up to a given accuracy
27  !
28  REAL(DP), PARAMETER :: eps4  = 1.0E-4_DP
29  REAL(DP), PARAMETER :: eps6  = 1.0E-6_DP
30  REAL(DP), PARAMETER :: eps8  = 1.0E-8_DP
31  REAL(DP), PARAMETER :: eps12 = 1.0E-12_DP
32  REAL(DP), PARAMETER :: eps14 = 1.0E-14_DP
33  REAL(DP), PARAMETER :: eps16 = 1.0E-16_DP
34  REAL(DP), PARAMETER :: eps24 = 1.0E-24_DP
35  REAL(DP), PARAMETER :: eps32 = 1.0E-32_DP
36  !
37  ! physical constants
38  !
39  REAL(DP), PARAMETER :: e2 = 2.0_DP      ! the square of the electron charge
40  !
41END MODULE upf_const
42
43