anchor.diff:            Y(I+N+1,I)= X(I )-DELTA                 
          END DO
       END DO
  -    DO I=1,  2*N+1 
  -       DO J=1, N
  +
  +    ! It is possible to use the value of the objective function at the
  +    ! center
  +    FF(1) = FX
  +    DO I = 2,2 * N + 1 
  +       DO J = 1,N
             YY(J) = Y(I,J) 
          END DO
          CALL CALFUN(N,YY,FF(I),FLAG)
  
positive.code:     intent(inout) :: delta,f,x
  
      ! LOCAL ARRAYS
      REAL(8) :: D(INN),XNOVO(INN),SL(INN),SU(INN), VETOR1(NPT+N+1),Z(INN)
  
      ! LOCAL SCALARS
      logical :: forbidden
  
negative.code: 
      END IF
  
      ! Evaluate the distance of the solution to z^k
  
      DISTSQ = (10.0D0 * RHO) ** 2.0D0                 
  
      DISTZ = 0.0D0
      DO I = 1,N
         DISTZ = MAX(DISTZ, ABS(X(I) - Z(I)))
      END DO
  
      ! If the distance to z^k is small, then verify if it is not time
      ! to stop the whole algorithm. Otherwise, try to build the model
      ! in a smaller radius.
  
      IF ( DISTZ .LT. 0.5D0 * RHO ) THEN 
  
         FEAS = 0.0D0
         do I = 1,M
  