C ENDO31    SOURCE    CHAT      05/01/12    23:38:53     5004           
        SUBROUTINE ENDO31(D3,D3R,WWY,AKK,ANN,DT) 
 
C Resolution Newton equation D3 
      IMPLICIT INTEGER(I-N)
        REAL*8 D3,D3R,WWY,akk,ann,DT 
        REAL*8 D31,PRE ,CC1,CC2,RI1,DRI1D,DD3,TEST 
        INTEGER IK 
 
        D31= D3R 
        PRE = 1.0D-6 
        IK=1 
 31      CONTINUE 
 
        CC1 =( DABS((WWY-D31)**ann) +(WWY-D31)**ann )/2.0D0 
        CC2 =( DABS((WWY-D31)**(ann-1)) +(WWY-D31)**(ann-1)  )/2.0D0 
        RI1= D31-D3R-AKK*DT*(CC1) 
        DRI1D= 1.0D0 +AKK*DT*(CC2) 
        DD3 = -RI1/ DRI1D 
        D31=D31 + DD3 
 
C Convergence Newton 
 
        Test = DABS(DD3) 
        IF(Test.le.PRE) THEN 
                   D3 = D31 
C       PRINT*,' Convergence Newton d3 Iteration',IK 
C       PRINT*,'ENDO D3',D3 
                    RETURN 
 
          ELSE 
 
        IK =IK +1 
 
                IF(IK.EQ. 100) THEN 
 
C       Print*,'Pas de convergence IKMAX',IK 
 
                    D3 = D3R 
                     RETURN 
                ELSE 
C Iterations Newton 
                        GOTO 31 
 
                ENDIF 
 
        ENDIF 
        END