Initial values of parameters: 
         ap =      1.00000E-01
         ao =     0.900000
         xo =     0.450000
 
 objective function =   0.181830525398E-01
 
 Final values of parameters: 
    ap (estimated)  =     0.116878
    ao (estimated)  =     0.936400
    xo (estimated)  =      3.25689E-02