C
      SUBROUTINE PEMAKEro(T,PE,ro,PEX)
C
C based on pemake but iterating on ro
C YOU FEED IT WITH T AND ro AND A GUESS PE. YOU GET PEX
C
      DATA IT,N,EPS/0,20,1.E-3/
C
C START
      A=ALOG(PE)
      PEX=PE
      CALL JON(T,PE,1,pg,fa,E,0,1)
C******WRITE(7,40) T,ro,PE,FA
40    FORMAT(' T,ro,PE,rop=',4E10.4)
      IT=IT+1
      FA=ALOG(FA/ro)
      IF(ABS(FA).LT.EPS) GOTO 101
      B=A-0.69*FA
      PEX=EXP(B)
C ONE PEMAKE ITERATION, CF. PEMAKE
      CALL JON(T,PEX,1,pg,fb,E,0,1)
C******WRITE(7,40) T,ro,PE,FB
      IT=IT+1
      FB=ALOG(FB/ro)
      IF(ABS(FB).LT.EPS) GOTO 101
      X=B
C
C LOOP
      DO 100 I=1,N
      XOLD=X
C
C INTERPOLATE TO FIND NEW X
      X=A-(B-A)/(FB-FA)*FA
      PEX=EXP(X)
      IF(ABS(X-XOLD).LT.EPS) GOTO 101
      CALL JON(T,PEX,1,pg,fx,E,0,1)
C******WRITE(7,40) T,ro,PEX,FX
      IT=IT+1
      FX=ALOG(FX/ro)
C
C CHECK IF A OR B CLOSEST TO X
      IF(ABS(A-X).LT.ABS(B-X)) GOTO 102
      A=X
      FA=FX
      GOTO 100
102   B=X
      FB=FX
C
C END OF LOOP
100   CONTINUE
      WRITE(7,51) N,T,PE,ro,A,B,FA,FB,EPS
51    FORMAT('0***PEMAKE, MAX ITER.: N,T,PE,ro,A,B,FA,FB,EPS=',
     * /,1X,I2,8E11.4)
      RETURN
C
C NORMAL END
101   CONTINUE
      RETURN
C
C COUNT ENTRY
      ENTRY PECNTro
      WRITE(7,52) IT
52    FORMAT('0TOTAL NUMBER OF CALLS TO JON FROM PEMAKE-R =',I5)
      RETURN
      END