max relative deviation FD vs closed form: 1.156086492814951e-22
min (log F)'' observed (should be > 0): 3.531153174135625e-10
s=0.01 r=0.01  (logF)''=1.465710e-39  closed=1.465710e-39
s=0.02 r=50  (logF)''=5.733403e-14  closed=5.733403e-14
s=50 r=0.02  (logF)''=9.545111e-03  closed=9.545111e-03
s=100 r=100  (logF)''=4.999892e-05  closed=4.999892e-05
s=0.05 r=0.5  (logF)''=7.802501e-05  closed=7.802501e-05
s=3 r=0.001  (logF)''=1.480343e-01  closed=1.480343e-01
