Table 7.

Comparison of various algorithms for the PET imaging problem. A 4,096-pixel image is recovered from photon coincidence counts collected from 2,016 detector tubes. Here the roughness constant is μ = 10⁻⁶, and the convergence criterion is ε = 10⁻⁸. The number of parameters is 4,096

Algorithm	Evals	Objective	Time
EM	3376	−15432.61	6836.05
q = 1	740	−15432.61	1743.55
q = 2	608	−15432.60	1432.38
q = 3	406	−15432.60	955.30
q = 4	372	−15432.57	875.51
q = 5	268	−15432.58	627.00
q = 6	222	−15432.57	520.97
q = 7	204	−15432.56	477.02
q = 8	188	−15432.54	441.48
q = 9	178	−15432.52	417.63
q = 10	176	−15432.51	411.20
q = 15	184	−15432.62	430.94
q = 20	236	−15432.45	559.32
SqS1	314	−15435.72	742.90
SqS2	290	−15432.54	684.79
SqS3	232	−15432.53	549.06