Add own function to read jackknife config file

main.py

@@ -43,6 +43,32 @@ def main():
               jackknife configuration file and the number of processes.
               Everything after that will be ignored.""")
 
+    general, observables = _read_config_file(config_file_name)
+
+    adga = Adga(general["adga_root_directory"], general["adga_config_file"],
+                general["two_particle_file"], observables, n_processes)
+    x_generator = adga.get_worm_sample_generator()
+    n = adga.n_worm_samples
+    f = adga.calculate_observables
+
+    # Do the Jackknife estimation
+    jackknife = Jackknife(x_generator, n, f, -1,
+                          general["output_file_prefix"],
+                          general["store_output_samples"])
+    jackknife.do_estimation()
+    jackknife.write_results_to_file()
+    adga.write_config_data_to_file(jackknife.output_file_name)
+    return
+
+
+def _read_config_file(config_file_name):
+    # Read and return general config data and observables from the given
+    # file.
+    #
+    # :raise KeyError: if an obligatory key is missing in the config
+    #                  file
+    # :raise SystemExit: if no observables are given in the config file
+    
     # Define the dictionary for the [General] section of the INI file.
     # Obligatory keys are set to `None`.
     general = {"adga_root_directory": None,
@@ -74,24 +100,10 @@ def main():
     for key in config["Observables"]:
         observables[key] = config["Observables"][key]
     if len(observables) == 0:
-        print("No Observables were given. Since you don't want to"
-              + " calculate anything we're done.")
-        sys.exit()
-
-    adga = Adga(general["adga_root_directory"], general["adga_config_file"],
-                general["two_particle_file"], observables, n_processes)
-    x_generator = adga.get_worm_sample_generator()
-    n = adga.n_worm_samples
-    f = adga.calculate_observables
+        raise SystemExit("No Observables were given. Since you don't want to"
+                         + " calculate anything we're done.")
 
-    # Do the Jackknife estimation
-    jackknife = jk.Jackknife(x_generator, n, f, -1,
-                          general["output_file_prefix"],
-                          general.getboolean("store_output_samples"))
-    jackknife.do_estimation()
-    jackknife.write_results_to_file()
-    adga.write_config_data_to_file(jackknife.output_file_name)
-    return
+    return general, observables
 
 
 if __name__ == "__main__":