C-----ANALYTICAL PROGRAM
C
C-----DECLARATIONS
C      
      REAL 
      REAL 
      INTEGER 
C
C-----INITIALISATION OF PARAMETERS
C
      DATA POR/0.2/,PERM/1.0/,VISC/1.0/,COMPR/0.0001/,L/100./,PL/2.0/
     *,PR/1.0/PINIT/1.0/,DT/0.0005/,N/10/,TMAX/0.01/,IPRINT/1/
      DATA PI/3.14159/
C
   31 DX=L/N
      T=0.
      CONST=DT/DX/DX*PERM/POR/VISC/COMPR
      ALPHA=1./CONST
      ISW=0
      DO 5 I=1,N
      P(I)=PINIT
      PNEW(I)=PINIT
    5 X(I)=L*I/N-L/N/2.
C
C-----OPEN OUTPUT FILE
C
      OPEN()
C
C-----TIME LOOP
C
      DO 200 J=1,1000
      ISW=ISW+1
      T=T+DT
C
C-----ANALYTICAL SOLUTION
C
    3 DO 8 I=1,N
      
      DO 11 K=1,1000
      
	  
	  
      IF(K.GT.10.AND.ABS(DP).LT.0.0000001)GOTO 8
   11 CONTINUE
    8 CONTINUE      
C
C-----PRINT (?)
C
      IF(ISW.NE.IPRINT)GO TO 99
      ISW=0
      WRITE(10,100)
  100 FORMAT(50F10.4)
   99 CONTINUE      
C
C-----END (?)
C
      IF(T.GE.TMAX)STOP
C
C-----UPDATING OF PRESSURES
C
   13 DO 14 I=1,N
   14 P(I)=PNEW(I)
  200 CONTINUE
      END

