Make CTG MinConflictsSolver deterministic

python-constraints now allows you to pass a PRNG to MinConflictsSolve which allows it to be deterministic. Version 2.0 is also apparently several orders of magnitude faster.

Author: Timmmm

requirements.txt

@@ -27,7 +27,7 @@ Pygments>=2.4.2
 pyparsing>=2.4.0
 pytablewriter
 pytest
-python-constraint>=1.4.0
+python-constraint2>=2.0.2
 python-dateutil>=2.8.0
 pytz>=2019.1
 pyyaml

riscv-ctg/riscv_ctg/generator.py

@@ -349,7 +349,8 @@ def opcomb(self, cgf):
         while any([len(op_conds[x])!=0 for x in op_conds]+[len(op_comb)!=0]):
             cond_str = ''
             cond_vars = []
-            solver = MinConflictsSolver() if self.random else None
+            # Use a fixed seed for MinConflictsSolver so it is deterministic.
+            solver = MinConflictsSolver(rand=random.Random(0)) if self.random else None
             problem = Problem(solver)
 
             done = False