Update threshold value in DGOperatorFactory and enhance AnalyticalStudyTests with BesselJ6 family tests

Co-authored-by: Copilot <copilot@github.com>

Author: AlejandroMunozManterola

src/components/DGOperatorFactory.h

@@ -1566,7 +1566,9 @@ namespace maxwell
 		// Free sub-operator blocks before applying threshold.
 		blocks.clear();
 
-		auto threshold = 1e-20;
+		// Threshold set to sqrt(eps_machine) ~ 1e-8, the standard criterion for distinguishing
+		// genuine matrix entries from floating-point assembly noise relative to unit-scale quantities.
+		auto threshold = 1e-8;
 		res->Threshold(threshold);
 
 		if(this->pd_.opts.export_evolution_operator){

test/cases/AnalyticalStudyTests.cpp

@@ -15,9 +15,9 @@ static void runBatchSweep(const std::string& case_prefix,
                           const std::string& case_suffix,
                           int p_min,
                           int p_max,
-                          const std::string& description)
+                          const std::string& description,
+                          const std::string& base_export_path = "./Exports/paper/")
 {
-    const std::string base_export_path = "./Exports/single-core/";
 
     int processed = 0;
     int missing = 0;
@@ -62,6 +62,32 @@ static void runResonantFamily(const std::string& suffix, const std::string& desc
     }
 }
 
+static void runBesselJ6Family(const std::string& suffix, const std::string& description)
+{
+    for (int g = 1; g <= 2; ++g) {
+        std::stringstream prefix;
+        prefix << "2D_BesselJ6_G" << g;
+        std::stringstream batch_desc;
+        batch_desc << description << " G" << g;
+        runBatchSweep(prefix.str(), suffix, 1, 5, batch_desc.str(), "./Exports/single-core/");
+    }
+}
+
+TEST_F(AnalyticalStudyTests, Batch_BesselJ6_Global_Closed)
+{
+    runBesselJ6Family("", "BesselJ6 Global Closed Basis");
+}
+
+TEST_F(AnalyticalStudyTests, Batch_BesselJ6_Hesthaven_Closed)
+{
+    runBesselJ6Family("_hesthaven", "BesselJ6 Hesthaven Closed Basis");
+}
+
+TEST_F(AnalyticalStudyTests, Batch_BesselJ6_Global_Open)
+{
+    runBesselJ6Family("_bleg", "BesselJ6 Global Open Basis");
+}
+
 TEST_F(AnalyticalStudyTests, Batch_TM55_Resonant_Box_Global_Closed)
 {
     runResonantFamily("", "TM55 Global Closed Basis");

testData/maxwellInputs/2D_Resonant_Box_TM55_Ha_Pb_Template/2D_Resonant_Box_TM55_Ha_Pb_Template.json

@@ -5,6 +5,7 @@
     "time_step": 0.0001,
     "basis_type": 1,
     "final_time": 2.8284,
+    "export_operator": true,
     "order": 1
   },
   "model": {