Extended statistics

[rtaupe]

Currently, Alpha is able to log a small number of statistical values on the solving process (cf. #51, #99, #102). To gather more data, it could be beneficial to log other values as well. Which ones should that be?

For example, clasp outputs something like the following:

Models : 1+ Calls : 1 Time : 28.071s (Solving: 27.05s 1st Model: 27.04s Unsat: 0.00s) CPU Time : 27.191s

Choices : 133724 Conflicts : 103856 (Analyzed: 103856) Restarts : 331 (Average: 313.76 Last: 167) Model-Level : 26.0 Problems : 1 (Average Length: 0.00 Splits: 0)

Lemmas : 103856 (Deleted: 77119)

Binary : 1655 (Ratio: 1.59%) Ternary : 2541 (Ratio: 2.45%) Conflict : 103856 (Average Length: 33.4 Ratio: 100.00%) Loop : 0 (Average Length: 0.0 Ratio: 0.00%) Other : 0 (Average Length: 0.0 Ratio: 0.00%)

Backjumps : 103856 (Average: 1.26 Max: 48 Sum: 130701)

Executed : 103856 (Average: 1.26 Max: 48 Sum: 130701 Ratio: 100.00%) Bounded : 0 (Average: 0.00 Max: 0 Sum: 0 Ratio: 0.00%)

Rules : 105814 Atoms : 36917 Bodies : 67239 Equivalences : 37788 (Atom=Atom: 303 Body=Body: 1758 Other: 35727) Tight : Yes Variables : 22212 (Eliminated: 0 Frozen: 0) Constraints : 85168 (Binary: 77.7% Ternary: 22.2% Other: 0.1%)