!!!!!!!!!!!!!!!!!!!!!!!!!!! Program 3.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! !
! Please Note: !
! !
! (1) This computer program is written by Tao Pang in conjunction with !
! his book, "An Introduction to Computational Physics," published !
! by Cambridge University Press in 1997. !
! !
! (2) No warranties, express or implied, are made for this program. !
! !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
PROGRAM ONE_D_MOTION2
!
! Simplest predictor-corector algorithm applied to a particle in one
! dimension under an elastic force. Copyright (c) Tao Pang 1997.
!
IMPLICIT NONE
INTEGER, PARAMETER :: N=101,IN=5
INTEGER :: I
REAL :: PI,DT
REAL, DIMENSION (N) :: T,V,X
!
PI = 4.0*ATAN(1.0)
DT =2.0*PI/100
X(1)=0.0
T(1)=0.0
V(1)=1.0
!
DO I = 1, N-1
T(I+1) = I*DT
!
! Predictor for position and velocity
!
X(I+1) = X(I)+V(I)*DT
V(I+1) = V(I)-X(I)*DT
!
! Corrector for position and velocity
!
X(I+1) = X(I)+(V(I)+V(I+1))*DT/2.0
V(I+1) = V(I)-(X(I)+X(I+1))*DT/2.0
END DO
WRITE(6,"(3F16.8)") (T(I),X(I),V(I),I=1,N,IN)
END PROGRAM ONE_D_MOTION2