dunkirk.sh
optimizing a gate level bcm to the end of the earth and back
Fix cost model to count ALL gate inputs (AND + OR)
- Total cost = AND gate inputs + OR gate inputs
- MaxSAT now optimizes for total cost, not just AND inputs
- Updated default target to 61 (no-sharing baseline)
Results:
No sharing: 61 total (33 AND + 28 OR)
Optimized: 52 total (15 AND + 37 OR)
Savings: 9 gate inputs (15% reduction)
Sharing reduces AND inputs dramatically (33→15) but increases
OR inputs (28→37) since shared terms fan out to more outputs.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
+2
-2
bcd_optimization/cli.py
+2
-2
bcd_optimization/cli.py
+10
-7
bcd_optimization/solver.py
+10
-7
bcd_optimization/solver.py
···
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cost_breakdown = self._compute_cost_breakdown(selected, implicants_by_output)
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return SynthesisResult(
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-
cost=cost_breakdown.and_inputs, # Primary cost = AND inputs only
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+
cost=cost_breakdown.total, # Total = AND inputs + OR inputs
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implicants_by_output=implicants_by_output,
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shared_implicants=shared,
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method="greedy",
···
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f"No implicant covers {segment}:{minterm}"
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)
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-
# Soft constraints: penalize each implicant by its AND gate cost
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# Single-literal terms (direct wires) have 0 AND cost
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# Multi-literal terms cost their literal count (AND gate inputs)
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# Soft constraints: penalize each implicant by its total gate input cost
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# Cost = AND inputs + OR inputs
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# - AND inputs: num_literals if >= 2, else 0 (single literals are wires)
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# - OR inputs: one per output this implicant covers
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for i, impl in enumerate(self.prime_implicants):
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and_cost = impl.num_literals if impl.num_literals >= 2 else 0
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if and_cost > 0:
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wcnf.append([-impl_vars[i]], weight=and_cost)
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+
or_cost = len(impl.covered_minterms) # Number of outputs it feeds
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total_cost = and_cost + or_cost
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if total_cost > 0:
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wcnf.append([-impl_vars[i]], weight=total_cost)
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# Solve
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with RC2(wcnf) as solver:
···
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cost_breakdown = self._compute_cost_breakdown(selected, implicants_by_output)
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return SynthesisResult(
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-
cost=cost_breakdown.and_inputs, # Primary cost = AND inputs only
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+
cost=cost_breakdown.total, # Total = AND inputs + OR inputs
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implicants_by_output=implicants_by_output,
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shared_implicants=shared,
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method="maxsat",