f = 9.700386e-01 f-delta = 7.9e-04
 Iter 23: f = 9.707283e-01 f-delta = 6.9e-04
 Iter 24: f = 9.713293e-01 f-delta = 6.0e-04
 Iter 25: f = 9.718507e-01 f-delta = 5.2e-04
 Iter 26: f = 9.723014e-01 f-delta = 4.5e-04
 Iter 27: f = 9.726898e-01 f-delta = 3.9e-04
 Iter 28: f = 9.730234e-01 f-delta = 3.3e-04
 Iter 29: f = 9.733095e-01 f-delta = 2.9e-04
 Iter 30: f = 9.735541e-01 f-delta = 2.4e-04
 Iter 31: f = 9.737631e-01 f-delta = 2.1e-04
 Iter 32: f = 9.739412e-01 f-delta = 1.8e-04
 Iter 33: f = 9.740930e-01 