C LAPLIN    SOURCE    CHAT      05/01/13    01:12:59     5004           
      SUBROUTINE LAPLIN
C     
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8     (A-H,O-Y)
      IMPLICIT COMPLEX*16 (Z)
C     
C CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
C     
C   OPERATEUR  LAPL
C     
C   CALCUL LA TRANSFORMEE DE LAPLACE INVERSE
C     
C     
C   SORTIES :
C     
C     
C   AUTEUR : SAINT-DIZIER ET DE LANGRE
C   DATE   : 05 DECEMBRE 1989
C     
C CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
C     
      LOGICAL INV

-INC CCREEL
-INC SMLREEL
-INC SMEVOLL
-INC CCOPTIO
C     
      SEGMENT MTRAV
      COMPLEX*16 ZW(NEXP)
      COMPLEX*16 ZXX(NPT)
      COMPLEX*16 ZYY(NPT)
      ENDSEGMENT
C     
      CALL LIROBJ('LISTREEL',MLREE1,1,IRETOU)
      IF (IERR.NE.0) RETURN
      CALL LIROBJ('LISTREEL',MLREE2,1,IRETOU)
      IF (IERR.NE.0) RETURN
      CALL LIROBJ('LISTREEL',MLREE3,1,IRETOU)
      IF (IERR.NE.0) RETURN
      CALL LIRREE(AA,1,IRETOU)
      IF (IERR.NE.0) RETURN
      CALL LIRENT(LL,1,IRETOU)
      IF (IERR.NE.0) RETURN
C     
      SEGACT MLREE1
      SEGACT MLREE2
      SEGACT MLREE3
C     
      NSUM = MLREE1.PROG(/1)
      NN = NSUM / LL
      JG = NN
      POINTEUR MLREE4.MLREEL
      POINTEUR MLREE5.MLREEL
      SEGINI MLREE4
      SEGINI MLREE5
C     
      NEXP = NN/2
      NPT  = NN
      SEGINI MTRAV
C     
      N  = 1
      SEGINI MEVOL1
      SEGINI KEVOL1
C     
C -- DETERMINATION DES CARACTERISTIQUES DU CALCUL
C     
      ZI = (0.D0,1.D0)
      T = 2.D0 * XPI / (MLREE1.PROG (2))
      DELTAT = T / NN
C     
C -- ALGORITHME DE DURBIN AVEC FFT
C     
      DO 20 K = 0 , NN - 1
         XA = 0D0
         XB = 0D0
         DO 21 KL= 0 , LL -1
            IKL =K + KL * NN
            XA = XA + MLREE2.PROG(IKL+1)
            XB = XB + MLREE3.PROG(IKL+1)
 21      CONTINUE
         ZXX(K + 1) = XA + ZI* XB
 20   CONTINUE
C     
      INV = .TRUE.
      CALL WEXP(INV,NPT,ZW)
      CALL FFTL(ZXX,ZYY,ZW,NPT)
C     
C     
      DO 30 J = 0 , NN-1
         TJ = J*DELTAT
         MLREE4.PROG(J+1)= TJ
         CJ = EXP(AA*TJ)
         FF =CXTORE(ZXX(J+1))
         MLREE5.PROG(J+1) = (2.D0*CJ/T)*(-.5D0*MLREE2.PROG(1)+FF)
C           MLREE5.PROG(J+1) = (2.D0*CJ/T)*(                   FF)
C           MLREE5.PROG(J+1) =                               FF
 30   CONTINUE
C     
      MEVOL1.ITYEVO = 'REEL'
      MEVOL1.IEVTEX = 'TRANSFORMEE DE LAPLACE'
      MEVOL1.IEVOLL(1) = KEVOL1
C     
      KEVOL1.IPROGX = MLREE4
      KEVOL1.IPROGY = MLREE5
      KEVOL1.NUMEVX = 0
      KEVOL1.TYPX   = 'LISTREEL'
      KEVOL1.TYPY   = 'LISTREEL'
      KEVOL1.NOMEVX = 'TEMPS'
      KEVOL1.NOMEVY = 'F(T)'
      KEVOL1.KEVTEX = 'LAPLACE INVERSE'
C     
      CALL ECROBJ('EVOLUTION',MEVOL1)
C     
      SEGDES MLREE1
      SEGDES MLREE2
      SEGDES MLREE3
      SEGDES MLREE4
      SEGDES MLREE5
      SEGDES MEVOL1
      SEGDES KEVOL1
      END