# of gridpoints: 100  grid parameter r0 =  10.
x=   5.   abs. error:  -0.000000119109639
x=  15.   abs. error:   0.000021333897367
x=  25.   abs. error:  -0.000063060587024
x=  35.   abs. error:   0.000085796220388
x=  45.   abs. error:  -0.001980729083856
x=  55.   abs. error:   0.006761497406923
x=  65.   abs. error:  -0.007390488358721
x=  75.   abs. error:   0.005559734282505
x=  85.   abs. error:  -0.009603618358942
x=  95.   abs. error:  -0.010277795881663

 # of gridpoints: 100  grid parameter r0 =  500.
x=   5.   abs. error:  -0.000000023974836
x=  15.   abs. error:   0.000000002986172
x=  25.   abs. error:   0.000002378134782
x=  35.   abs. error:   0.000002574244076
x=  45.   abs. error:   0.000027561045480
x=  55.   abs. error:   0.000031586121042
x=  65.   abs. error:   0.000034091428713
x=  75.   abs. error:  -0.000036122802056
x=  85.   abs. error:  -0.000237931386422
x=  95.   abs. error:  -0.000654532720617