Apply segfaultl fixes to surface code 2 and 3

Signed-off-by: Chuck Ketcham <[email protected]>

Author: cketcham2333

libs/qec/unittests/realtime/app_examples/surface_code-2.cpp

@@ -45,12 +45,9 @@ void save_dem_to_file(const cudaq::qec::detector_error_model &dem,
     config.O_sparse =
         cudaq::qec::pcm_to_sparse_vec(dem.observables_flips_matrix);
     config.D_sparse = std::vector<int64_t>(det_mat);
-    config.decoder_custom_args =
-        cudaq::qec::decoding::config::multi_error_lut_config();
-    auto &multi_error_lut_config =
-        std::get<cudaq::qec::decoding::config::multi_error_lut_config>(
-            config.decoder_custom_args);
-    multi_error_lut_config.lut_error_depth = 2;
+    cudaq::qec::decoding::config::multi_error_lut_config lut_config;
+    lut_config.lut_error_depth = 2;
+    config.decoder_custom_args = lut_config;
     multi_config.decoders.push_back(config);
   }
   std::string config_str = multi_config.to_yaml_str(200);

libs/qec/unittests/realtime/app_examples/surface_code-3.cpp

@@ -43,12 +43,9 @@ create_decoder_config(uint64_t id, const cudaq::qec::detector_error_model &dem,
   config.H_sparse = cudaq::qec::pcm_to_sparse_vec(dem.detector_error_matrix);
   config.O_sparse = cudaq::qec::pcm_to_sparse_vec(dem.observables_flips_matrix);
   config.D_sparse = det_mat;
-  config.decoder_custom_args =
-      cudaq::qec::decoding::config::multi_error_lut_config();
-  auto &multi_error_lut_config =
-      std::get<cudaq::qec::decoding::config::multi_error_lut_config>(
-          config.decoder_custom_args);
-  multi_error_lut_config.lut_error_depth = 2;
+  cudaq::qec::decoding::config::multi_error_lut_config lut_config;
+  lut_config.lut_error_depth = 2;
+  config.decoder_custom_args = lut_config;
   return config;
 }