Write results on file also for single_run

in addition to printing a summary on standard output
Modified the settings.json template adding the output_file flag
Added an example of csv results file for single run

examples/result_single_run.csv

@@ -0,0 +1,2 @@
+beta,initial_s0,H,GAMMA,measured_sigmax,measured_sigmaz,N_measures,N_attempted_flips,N_accepted_flips,N_attempted_addsegment,N_accepted_addsegment,N_attempted_removesegment,N_accepted_removesegment,max_diagram_order,avg_diagram_order,run_time,N_total_steps,N_thermalization_steps,update_choice_seed,diagram_seed
+1,1,1,1,-0.627866,-0.628183,50000000,16671384,5471745,16661864,4236089,16666752,4236089,10,0,2216023100,50000000,0,1694693316578956500,1694693316578957400

examples/settings_singlerun.json

@@ -1,6 +1,9 @@
 {
     "CALC_TYPE" : "single",
 
+    "output_file" : "result_single_run.csv",
+
+
     "beta" : 1,
     "H" : 1,
     "GAMMA" : 1,

src/setup.cpp

@@ -184,6 +184,7 @@ void single_run(const json & settings)
             "H",
             "GAMMA",
             "N_total_steps",
+            "output_file"
         }
     );
 
@@ -195,11 +196,16 @@ void single_run(const json & settings)
     //############################################################################
 
 
+    //open file stream to write results in output file, write the header row containing the titles of the columns
+    std::ofstream output_file_stream(static_cast<std::string>(settings["output_file"]));
+    output_file_stream << SingleRunResults::ostream_output_header();
+
+
     //SIMULATION#################################################################
     std::cout<<"Running single run simulation...\n";
 
     //execute single run simulation, and print results to terminal standard output
-    run_simulation( 
+    SingleRunResults results = run_simulation( 
         settings["beta"],
         initial_s0, 
         settings["H"], 
@@ -208,7 +214,12 @@ void single_run(const json & settings)
         N_thermalization_steps, 
         update_choice_seed, 
         diagram_seed
-    ).print_results();
+    );
+    output_file_stream << results;    
+    output_file_stream.close();
+
+    //for single run, also print summary on console standard output
+    results.print_results();
     //############################################################################
 
 }