#include "isajet/pilot.h"
      SUBROUTINE EVOLVE
C----------------------------------------------------------------------
C-
C-   Purpose and Methods : 
C-        Call for each process a subroutine to set up
C-        Lorentz frames and perform initial and final QCD jet
C-        evolution in leading-log approximation.
C-
C-   Created  13-AUG-1991   Frank E. Paige,Serban D. Protopopescu
C-
C----------------------------------------------------------------------
#if defined(CERNLIB_IMPNONE)
      IMPLICIT NONE
#endif
#include "isajet/primar.inc"
#include "isajet/jetpar.inc"
#include "isajet/pjets.inc"
#include "isajet/pinits.inc"
#include "isajet/jetset.inc"
#include "isajet/jwork.inc"
#include "isajet/jwork2.inc"
#include "isajet/keys.inc"
#include "isajet/frame.inc"
      REAL BP,PINCOM
      INTEGER I,K,J,JJET,IFR
C----------------------------------------------------------------------
C          Initialize
      NJSET=0
      N0JETS=0
      N0W=0
      N0PAIR=0
C
C          Copy momenta from /PINITS/ to /JETSET/
      IF(.NOT.KEYS(2)) THEN
        DO 100 I=1,2
          NJSET=NJSET+1
          JORIG(NJSET)=JPACK*(10+I)
          JTYPE(NJSET)=IDINIT(I)
          JDCAY(NJSET)=JPACK*I+I
          DO 105 K=1,5
105       PJSET(K,NJSET)=PINITS(K,I)
100     CONTINUE
      ENDIF
C
C       Handle each process separately
C
      IF(KEYS(1).OR.KEYS(8)) THEN
        CALL EVOL01
      ELSEIF(KEYS(2)) THEN
        CALL EVOL02
      ELSEIF(KEYS(3)) THEN
        CALL EVOL03
      ELSEIF(KEYS(5)) THEN
        CALL EVOL05
      ELSEIF(KEYS(6).OR.KEYS(10)) THEN
        CALL EVOL06
      ELSEIF(KEYS(7).OR.KEYS(9)) THEN
        CALL EVOL07
      ENDIF
C
      IF(NJSET.LT.0) RETURN
C
C          Boost /JETSET/ partons back to PP COM
C
      DO 500 J=1,NJSET
        JJET=JORIG(J)/JPACK
        IF ( JJET.EQ.0 ) THEN
          IFR=1
        ELSE
          IF(JJET.GT.10) GO TO 500
          IF(IDJETS(JJET).EQ.10.AND.KEYS(6)) GO TO 500
          IFR=IFRAME(JJET)
        ENDIF
        BP=0.
        DO 505 K=1,3
505     BP=BP+FRAME(K,IFR)*PJSET(K,J)
        BP=BP/FRAME(5,IFR)
        DO 510 K=1,3
510     PJSET(K,J)=PJSET(K,J)+FRAME(K,IFR)*PJSET(4,J)/FRAME(5,IFR)
     1  +FRAME(K,IFR)*BP/(FRAME(4,IFR)+FRAME(5,IFR))
        PJSET(4,J)=FRAME(4,IFR)*PJSET(4,J)/FRAME(5,IFR)+BP
500   CONTINUE
C
C          Reset PBEAM
      DO 530 J=1,NJSET
        IF(JDCAY(J).EQ.JPACK*J+J) THEN
          JJET=JORIG(J)/JPACK-10
          PINCOM=.5*(PJSET(4,J)+ABS(PJSET(3,J)))
          PBEAM(JJET)=HALFE-PINCOM
        ENDIF
530   CONTINUE
C
C          Check for zero energy partons
      CALL IRMOV0
C
      RETURN
      END