PROGRAM Gaussian
! ------------------------------------------------------------------------------
!
! Copyright 2007 Matthew Norton
!
! ------------------------------------------------------------------------------
!    This program 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 2 of the License, or
!    (at your option) any later version.
!
!    This program 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 this program; if not, write to the Free Software
!    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
!
! NOTE: This is in FORTRAN 90 and you will need a FORTRAN 90 complier to run 
! this code
! ------------------------------------------------------------------------------
!
! This program uses gaussian integration to approximate the area of a 
! gaussian shaped bag traveling over a bridge
!
! ------------------------------------------------------------------------------
IMPLICIT NONE

REAL*8 :: Roe1, Roe2, Roe3, Roe4, Mass, PI, X, U, T, Node1, Node2, Weight1, Weight2
INTEGER :: I
REAL*8, PARAMETER :: V = 1
PI = ACOS(-1.)
PRINT *, Pi
OPEN(UNIT = 10, FILE = "Gauss.txt")
Node1 = .339981043584856
Node2 = .861136311594053
Weight1 = 0.652145154862546
Weight2 = 0.347854845137454

X = -5.
DO I = 0, 1000
	 T = REAL(I)* .01
	 U = -Node1 + 5 - T
	 Roe1 = (10. / SQRT(PI)) * 1. / (EXP((U * U) ))
	 U = -Node2 + 5 - T
	 Roe2 = (10. / SQRT(PI)) * 1. / (EXP((U * U) ))
	 U = Node1 + 5 - T
	 Roe3 = (10. / SQRT(PI)) * 1. / (EXP((U * U) ))
	 U = Node2 + 5 - T
	 Roe4 = (10. / SQRT(PI)) * 1. / (EXP((U * U) )) 
	 
	 Mass =   Weight1 * Roe1 + Weight2 * Roe2 + Weight1 * Roe3 + Weight2 * Roe4 
	 
	 !WRITE(10, '(1X, f10.7, 1X, F12.9)') T, Mass
	 !WRITE(6, '(1X, f10.7, 1X, F12.9)') T, Mass
	 WRITE(10, *) T, Mass
	 WRITE(6, *) T, Mass 	 	  	 
END DO
END PROGRAM