!********************************************************
!*                 TIME  PERT  MODEL                    *
!*                                                      *
!* LIST OF MAIN VARIABLES;                              *
!*                                                      *
!* N        ; NUMBER OF ACTIVITIES                      *
!* NA       : NUMBER OF PRECEDING ACTIVITIES            *
!* D(N)     ; PROBABLE DURATION FOR EACH ACTIVITY       *
!* PRED(N)  ; INDEX OF PRECEDING ACTIVITIES             *
!* ANTE(NA) ; PRECEDING ACTIVITIES OF EACH ACTIVITY     *
!* MARQ(2,N); ACTIVITY LEVEL                            *
!* TOT(N)   ; SOONEST DATE FOR EACH ACTIVITY            *
!* TARD(N)  ; LATEST DATE FOR EACH ACTIVITY             *
!* DE       ; ESTIMATED DURATION                        *
!* DOP      ; OPTIMISTIC DURATION (DO IS NOT VALID)     *
!* DP       ; PESSIMISTIC DURATION                      *
!* ANTE     ; NUMBER OF PREVIOUS ACTIVITIES             *
!* K        ; NUMBER OF ACTIVITY LEVEL                  *
!* R        ; USED TO SEEK A LEVEL                      *
!* TOT      ; USED TO SEEK SOONEST DATE                 *
!* TARD     ; USED TO SEEK LATEST DATE                  *
!* FTA      ; LATEST ENDING DATE                        *
!* FOT      ; SOONEST ENDING DATE                       *
!* XLO      ; MAXIMUM WIDTH OG GANT'S DIAGRAM           *
!* XMAXT    ; PROBABLE MAXIMUM TIME                     *
!* X        ; NORMALIZATION COEFFICIENT FOR GANT'S      *
!*            DIAGRAM                                   *
!* Y        ; NUMBER OF UNITS FOR A SIGN * OR + IN      *
!*            GANT'S DIAGRAM                            *
!* ---------------------------------------------------- *
!* PROBLEM DESCRIPTION;                                 *
!* A Company, owning one mainframe computer, wants to   *
!* buy and install a second one. Before a false floor   *
!* must be laid to hide connection cables, and an air-  *
!* conditioning unit must be put in. The activities to  *
!* perform are given in the following table (durations  *
!* in hours);                                           *
!*   -------------------------------------------------  *
!*   Number  Task Description   Preceding  DE  DO  DP   *
!*                              Activities              *
!*   -------------------------------------------------  *
!*     1     Set the Dates of                           *
!*           All the Tasks          -       3   2   4   *
!*     2     Install Electric                           *
!*           Connections            1       7   4  10   *
!*     3     Install Air Condit.    2      16   8  24   *
!*     4     Disconnect Old                             *
!*           Computer               2       4   2   6   *
!*     5     Start New Air Cond.    3       2   1   3   *
!*     6     Lay False Floor       3,4     24  16  32   *
!*     7     Clean Up the Room      6       3   2   4   *
!*     8     Install New Computer  5,7     16   8  24   *
!*     9             ---            8       0   0   0   *
!*   -------------------------------------------------  *
!* SAMPLE RUN;                                          *
!*                  TIME PERT MODEL                     *
!*               ACTIVITY DESCRIPTION                   *
!*                                                      *
!* NUMBER OF ACTIVITIES ? 9                             *
!*                                                      *
!* ACTIVITY #1;                                         *
!*   ESTIMATED DURATION   ? 3                           *
!*   OPTIMISTIC DURATION  ? 2                           *
!*   PESSIMISTIC DURATION ? 4                           *
!*   NUMBER OF PRECEDING ACTIVITIES ? 0                 *
!*                                                      *
!* ACTIVITY #2;                                         *
!*   ESTIMATED DURATION   ? 7                           *
!*   OPTIMISTIC DURATION  ? 4                           *
!*   PESSIMISTIC DURATION ? 10                          *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 1                              *
!*                                                      *
!* ACTIVITY #3;                                         *
!*   ESTIMATED DURATION   ? 16                          *
!*   OPTIMISTIC DURATION  ? 8                           *
!*   PESSIMISTIC DURATION ? 24                          *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 2                              *
!*                                                      *
!* ACTIVITY #4;                                         *
!*   ESTIMATED DURATION   ? 4                           *
!*   OPTIMISTIC DURATION  ? 2                           *
!*   PESSIMISTIC DURATION ? 6                           *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 2                              *
!*                                                      *
!* ACTIVITY #5;                                         *
!*   ESTIMATED DURATION   ? 2                           *
!*   OPTIMISTIC DURATION  ? 1                           *
!*   PESSIMISTIC DURATION ? 3                           *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 3                              *
!*                                                      *
!* ACTIVITY #6;                                         *
!*   ESTIMATED DURATION   ? 24                          *
!*   OPTIMISTIC DURATION  ? 16                          *
!*   PESSIMISTIC DURATION ? 32                          *
!*   NUMBER OF PRECEDING ACTIVITIES ? 2                 *
!*   PREC. ACTIVITY #1 ? 3                              *
!*   PREC. ACTIVITY #2 ? 4                              *
!*                                                      *
!* ACTIVITY #7;                                         *
!*   ESTIMATED DURATION   ? 3                           *
!*   OPTIMISTIC DURATION  ? 2                           *
!*   PESSIMISTIC DURATION ? 4                           *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 6                              *
!*                                                      *
!* ACTIVITY #8;                                         *
!*   ESTIMATED DURATION   ? 16                          *
!*   OPTIMISTIC DURATION  ? 8                           *
!*   PESSIMISTIC DURATION ? 24                          *
!*   NUMBER OF PRECEDING ACTIVITIES ? 2                 *
!*   PREC. ACTIVITY #1 ? 5                              *
!*   PREC. ACTIVITY #2 ? 7                              *
!*                                                      *
!* ACTIVITY #9;                                         *
!*   ESTIMATED DURATION   ? 0                           *
!*   OPTIMISTIC DURATION  ? 0                           *
!*   PESSIMISTIC DURATION ? 0                           *
!*   NUMBER OF PRECEDING ACTIVITIES ? 1                 *
!*   PREC. ACTIVITY #1 ? 8                              *
!*                                                      *
!*                  TIME PERT MODEL                     *
!*                      RESULTS                         *
!*                                                      *
!*   CA  = CRITICAL ACTIVITY                            *
!*   SBD = SOONEST BEGIN DATE                           *
!*   LBD = LATEST BEGIN DATE                            *
!*   SED = SOONEST END DATE                             *
!*   LED = LATEST END DATE                              *
!*                                                      *
!*   ACTIVITY #1  PROBABLE DURATION; 3  * CA *          *
!*     SBD = 0   LBD = 0                                *
!*     SED = 3   LED = 3                                *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ACTIVITY #2  PROBABLE DURATION; 7  * CA *          *
!*     SBD = 3   LBD = 3                                *
!*     SED = 10  LED = 10                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ACTIVITY #3  PROBABLE DURATION; 16  * CA *         *
!*     SBD = 10  LBD = 10                               *
!*     SED = 26  LED = 26                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ANY KEY TO CONTINUE... ?                           *
!*                                                      *                                               
!*   ACTIVITY #4  PROBABLE DURATION; 4                  *
!*     SBD = 10  LBD = 22                               *
!*     SED = 14  LED = 26                               *
!*     TOTAL MARGIN = 12                                *
!*                                                      *
!*   ACTIVITY #5  PROBABLE DURATION; 2                  *
!*     SBD = 26  LBD = 51                               *
!*     SED = 28  LED = 53                               *
!*     TOTAL MARGIN = 25                                *
!*                                                      *
!*   ACTIVITY #6  PROBABLE DURATION; 24  * CA *         *
!*     SBD = 26  LBD = 26                               *
!*     SED = 50  LED = 50                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ANY KEY TO CONTINUE... ?                           *
!*                                                      *
!*   ACTIVITY #7  PROBABLE DURATION; 3  * CA *          *
!*     SBD = 50  LBD = 50                               *
!*     SED = 53  LED = 53                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ACTIVITY #8  PROBABLE DURATION; 16  * CA *         *
!*     SBD = 53  LBD = 53                               *
!*     SED = 69  LED = 69                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ACTIVITY #9  PROBABLE DURATION; 0  * CA *          *
!*     SBD = 69  LBD = 69                               *
!*     SED = 69  LED = 69                               *
!*     TOTAL MARGIN = 0                                 *
!*                                                      *
!*   ANY KEY TO CONTINUE... ?                           *
!*                                                      *
!*   GANT'S DIAGRAM                                     *
!*                                                      *
!*   THE SIGNS * OR + ARE WORTH 3 TIME UNITS            *
!*                                                      *
!*   -------------------------------------------        *
!*    *  3.                                             *
!*    *** 10.                                           *
!*        ******** 26.                                  *
!*        **++++++ 26.                                  *
!*                 *++++++++++++ 53.                    *
!*                 ************ 50.                     *
!*                             * 53.                    *
!*                              ******** 69.            *
!*   -------------------------------------------        *
!*   * = PROBABLE DURATION    + = TOTAL MARGIN          *
!*                                                      *
!* ---------------------------------------------------- *
!* REFERENCE;                                           *
!* Modèles pratiques de décision Tome 2, By Jean-Pierre *
!* Blanger, PSI Editions, France, 1982.                 *
!*                                                      *
!*                F90 Release 1.0 By J-P Moreau, Paris. *
!*                          (www.jpmoreau.fr)           *
!********************************************************
!NOTE: PERT is an acronym for Program Evaluation & Review Technique.

PROGRAM TPERT

parameter(NMAX=12)

REAL    D(0:NMAX), TOT(0:NMAX), TARD(0:NMAX)
INTEGER ANTE(0:NMAX), PRED(0:NMAX), MARQ(1:2,0:NMAX)

  Call Data(N,D,ANTE,PRED)                   !DESCRIBE ACTIVITIES
  Call Level(N,K,MARQ,ANTE,PRED)             !DETERMINE LEVEL
  Call SDates(N,K,D,MARQ,ANTE,PRED,TOT)      !SOONEST DATES
  Call LDates(N,K,D,MARQ,ANTE,PRED,TOT,TARD) !LATEST DATES
  Call EDates(N,D,TOT,TARD)                  !EDIT DATES
  Call Gant(N,D,TOT,TARD)                    !GANT'S DIAGRAM

  STOP

END

Subroutine Data(N,D,ANTE,PRED)   !DESCRIBE ACTIVITIES
parameter(NMAX=12)
REAL    D(0:NMAX)
INTEGER ANTE(0:NMAX), PRED(0:NMAX)
     PRED(0)=0
     ANTE(0)=0; ANTE(1)=0
     PRINT *,' '
     PRINT *,'                  TIME PERT MODEL'
	 PRINT *,'                ACTIVITY DESCRIPTION'
	 PRINT *,' '
	 WRITE(*,10,advance='no'); READ *, N
	 DO I=1, N
	   PRINT *,' '
	   WRITE(*,20) I
	   WRITE(*,30,advance='no'); READ *, DE
       WRITE(*,40,advance='no'); READ *, DOP
	   WRITE(*,50,advance='no'); READ *, DP
	   D(I) = INT(10 * (DOP + 4 * DE + DP) / 6) / 10.
	   WRITE(*,60,advance='no'); READ *, IANTE
       IF (IANTE.EQ.0) THEN
	     IANTE=1; GOTO 100
       END IF
       DO J=1, IANTE
	     WRITE(*,70,advance='no')  J
		 READ *, ANTE(PRED(I-1)+J) 
       END DO
100    PRED(I)=PRED(I-1) + IANTE
	 END DO 
     PRINT *,'                  TIME PERT MODEL'
     PRINT *,'                      RESULTS'
     PRINT *,' '
     RETURN
10 FORMAT(' NUMBER OF ACTIVITIES ? ')
20 FORMAT(' ACTIVITY #',I1,':')
30 FORMAT('   ESTIMATED DURATION   ? ')
40 FORMAT('   OPTIMISTIC DURATION  ? ')
50 FORMAT('   PESSIMISTIC DURATION ? ')
60 FORMAT('   NUMBER OF PRECEDING ACTIVITIES ? ')
70 FORMAT('   PREC. ACTIVITY #',I1,' ? ') 
END

Subroutine Level(N,K,MARQ,ANTE,PRED)   !Determine Level
parameter(NMAX=12)
INTEGER MARQ(1:2,0:NMAX), ANTE(0:NMAX), PRED(0:NMAX)
INTEGER F,R
     MARQ(2, 0) = 1
     DO I = 1, N
       K = K + 1
       DO J = 1, N
         IF (MARQ(2, J).NE.0) GOTO 130
         DO R = PRED(J - 1) + 1, PRED(J)
           IF (MARQ(2, ANTE(R)).EQ.0) F = 1
         END DO
         IF (F.EQ.1) THEN
		   F = 0; GOTO 130
         END IF
         DO R = PRED(J - 1) + 1, PRED(I)
           MARQ(1, J) = K
         END DO
130    END DO
       DO J = 1, N
         IF (MARQ(1, J).EQ.K)  MARQ(2, J) = K
       END DO
     END DO
     K = MARQ(2, 1)
     DO I = 1, N
       IF (MARQ(2, I) > K)  K = MARQ(2, I)
     END DO
     RETURN
END

Subroutine SDates(N,K,D,MARQ,ANTE,PRED,TOT)  !SOONEST DATES
parameter(NMAX=12)
INTEGER MARQ(1:2,0:NMAX), ANTE(0:NMAX), PRED(0:NMAX)
REAL D(0:NMAX), TOT(0:NMAX)
     DO I = 1, K
       DO J = 1, N
         IF (MARQ(2, J).NE.I)  GOTO 10
         DO I1 = PRED(J - 1) + 1, PRED(J)
           XTOT = INT(10. * (TOT(ANTE(I1)) + D(ANTE(I1)))) / 10.
           IF (TOT(J).EQ.0.)  TOT(J) = XTOT
           IF (XTOT > TOT(J))  TOT(J) = XTOT
         END DO
10     END DO
     END DO
     RETURN
END

Subroutine LDates(N,K,D,MARQ,ANTE,PRED,TOT,TARD)  !LATEST DATES
parameter(NMAX=12)
INTEGER MARQ(1:2,0:NMAX), ANTE(0:NMAX), PRED(0:NMAX)
REAL D(0:NMAX), TOT(0:NMAX), TARD(0:NMAX)
     DO I = 1, N
       IF (MARQ(2,I).EQ.K)  THEN
	     TARD(I) = TOT(I)
		 GOTO 5
       END IF
     END DO
5    DO I = K, 1, -1
       DO J = 1, N
         IF (MARQ(2, J).NE.I) GOTO 20
         DO I1 = PRED(J - 1) + 1, PRED(J)
           XTARD = INT(10. * (TARD(J) - D(ANTE(I1)))) / 10.
           IF (TARD(ANTE(I1)).EQ.0.) THEN
             TARD(ANTE(I1)) = XTARD; GOTO 10
           END IF
           IF (TARD(ANTE(I1)) > XTARD)  TARD(ANTE(I1)) = XTARD
10       END DO
20     END DO
     END DO
     RETURN
END

Subroutine EDates(N,D,TOT,TARD)  !EDIT DATES
parameter(NMAX=12)
REAL D(0:NMAX), TOT(0:NMAX), TARD(0:NMAX)
     PRINT *,'   CA  = CRITICAL ACTIVITY'
     PRINT *,'   SBD = SOONEST BEGIN DATE'
     PRINT *,'   LBD = LATEST BEGIN DATE'
     PRINT *,'   SED = SOONEST END DATE'
     PRINT *,'   LED = LATEST END DATE'
     PRINT *,' '
     DO I = 1, N
       FTA = TARD(I) + D(I); FOT = TOT(I) + D(I)
       XMT = TARD(I) - TOT(I)
       IF (XMT.EQ.0.) THEN 
	     WRITE(*,51) I, D(I)
       ELSE
	     WRITE(*,50) I, D(I)
       END IF
	   WRITE(*,60) TOT(I), TARD(I)
       WRITE(*,61) FOT, FTA
       WRITE(*,70) XMT
       PRINT *,' '
       IF (MOD(I,3).NE.0.OR.I.EQ.N) GOTO 20
       PAUSE ' ANY KEY TO CONTINUE... '
20   END DO
     PAUSE ' ANY KEY TO CONTINUE... '
     RETURN
50 FORMAT(' ACTIVITY #',I1,'  PROBABLE DURATION: ',F5.2)
51 FORMAT(' ACTIVITY #',I1,'  PROBABLE DURATION: ',F5.2,'  * CA *')
60 FORMAT('   SBD = ',F5.2,'  LBD = ',F5.2)
61 FORMAT('   SED = ',F5.2,'  LED = ',F5.2)
70 FORMAT('   TOTAL MARGIN = ', F5.2)
END

Subroutine Gant(N,D,TOT,TARD)   !GANT'S DIAGRAM
parameter(NMAX=12)
REAL D(0:NMAX), TARD(0:NMAX), TOT(0:NMAX)
INTEGER Y
      LO = 35; MAXT = 0
      PRINT *,' GANT''S DIAGRAM'
      PRINT *,' '
      DO I = 1, N
        IF (TOT(I) + D(I) > MAXT)  MAXT = TOT(I) + D(I)
      END DO
      IF (MAXT < LO) THEN 
	    X = 1.0; GOTO 100
      END IF
      X = INT(10. * LO / MAXT) / 10.; Y = INT(1.0*MAXT/LO/X)
100   WRITE(*,300)  Y
      PRINT *,'--------------------------------------------'
      DO I = 1, N - 1
        L = INT(TOT(I) * X)
        DO J = 1, L+1
		  WRITE(*,310,advance='no') 
		END DO
        L = INT(D(I) * X); IF (L.EQ.0) GOTO 170
        DO J = 1, L
		  WRITE(*,320,advance='no') 
		END DO
170     L = INT((TARD(I) - TOT(I)) * X)
        IF (L.EQ.0) GOTO 200
        DO J = 1, L
		  WRITE(*,330,advance='no') 
		END DO
200     WRITE(*,340)  TARD(I) + D(I)
      END DO
      PRINT *,'--------------------------------------------'
      PRINT *,' * = PROBABLE DURATION    + = TOTAL MARGIN'
      PRINT *,' '
     RETURN
300  FORMAT(' THE SIGNS * OR + ARE WORTH', I2, ' TIME UNITS')
310  FORMAT(' ')
320  FORMAT('*')
330  FORMAT('+')
340  FORMAT(F4.0)
END
     
!end of file tpert.f90