⚡ change the default AMO and EO encoding (#309)

## Description

This PR changes the default for the encoding of at-most-one and
exactly-one constraints used in the exact mapping approach.
For some (unknown) reason, the default was still using the `naive`
encoding although the commander encoding is superior in practically
every aspect.
This should improve the out-of-the-box performance when using the exact
mapping approach across the board.

## Checklist:

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- [x] The pull request only contains commits that are related to it.
- [x] I have added appropriate tests and documentation.
- [x] I have made sure that all CI jobs on GitHub pass.
- [x] The pull request introduces no new warnings and follows the
project's style guidelines.

Signed-off-by: Lukas Burgholzer <[email protected]>

include/configuration/Configuration.hpp

@@ -56,8 +56,8 @@ struct Configuration {
   std::size_t timeout = 3600000; // 60min timeout
 
   // encoding of at most and exactly one constraints in exact mapper
-  Encoding          encoding          = Encoding::Naive;
-  CommanderGrouping commanderGrouping = CommanderGrouping::Halves;
+  Encoding          encoding          = Encoding::Commander;
+  CommanderGrouping commanderGrouping = CommanderGrouping::Fixed3;
 
   // use qubit subsets in exact mapper
   bool useSubsets = true;

mqt/qmap/compile.py

@@ -64,8 +64,8 @@ def compile(  # noqa: A001
     use_teleportation: bool = False,
     teleportation_fake: bool = False,
     teleportation_seed: int = 0,
-    encoding: str | Encoding = "naive",
-    commander_grouping: str | CommanderGrouping = "halves",
+    encoding: str | Encoding = "commander",
+    commander_grouping: str | CommanderGrouping = "fixed3",
     use_bdd: bool = False,
     swap_reduction: str | SwapReduction = "coupling_limit",
     swap_limit: int = 0,

test/test_exact.cpp

@@ -431,6 +431,7 @@ TEST_F(ExactTest, WCNFNotAvailable) {
   using namespace qc::literals;
 
   settings.verbose     = false;
+  settings.encoding    = Encoding::Naive;
   settings.includeWCNF = true;
 
   auto circ = qc::QuantumComputation(5U);