# of gridpoints: 100  grid parameter r0 =  50.
x=   5.   abs. error:   0.000000214667068
x=  15.   abs. error:  -0.000000007609742
x=  25.   abs. error:  -0.000000010457327
x=  35.   abs. error:  -0.000000005499118
x=  45.   abs. error:  -0.000000000395360
x=  55.   abs. error:   0.000000004283635
x=  65.   abs. error:   0.000000008378677
x=  75.   abs. error:   0.000000011825179
x=  85.   abs. error:   0.000000014601973
x=  95.   abs. error:   0.000000016719994