Merge branch 'fix/#608-postprocessing-only-for-converged-solutions' i…

…nto dev

docs/whats_new/v0-7-9.rst

@@ -13,6 +13,13 @@ New Features
   use the feature check the documentation of the component class
   (`PR #602 <https://github.com/oemof/tespy/pull/602>`__).
 
+Bug Fixes
+#########
+- Run the postprocessing only for a converged solution. Otherwise specified
+  values on buses, components or connections may change to nonsense, because
+  the calculation is based on not-converged results of the variables
+  (`PR #609 <https://github.com/oemof/tespy/pull/609>`__).
+
 Contributors
 ############
 - `@tlmerbecks <https://github.com/tlmerbecks>`__

src/tespy/components/reactors/water_electrolyzer.py

@@ -176,10 +176,10 @@ class WaterElectrolyzer(Component):
     >>> round(el.eta.val, 1)
     0.8
     >>> el_cmp.set_attr(v=None)
-    >>> el.set_attr(P=P_design * 0.66)
+    >>> el.set_attr(P=P_design * 1e6 * 0.2)
     >>> nw.solve('offdesign', design_path='tmp')
     >>> round(el.eta.val, 2)
-    0.88
+    0.84
     >>> shutil.rmtree('./tmp', ignore_errors=True)
     """
 

src/tespy/networks/network.py

@@ -1109,9 +1109,11 @@ def presolve_fluid_topology(self):
                 main_conn.fluid.val.update(fixed_fractions)
                 main_conn.fluid.is_set = {f for f in fixed_fractions}
                 main_conn.fluid.is_var = variable
-                num_var = len(variable)
-                for f in variable:
-                    main_conn.fluid.val[f]: (1 - mass_fraction_sum) / num_var
+                # this seems to be a problem in some cases, e.g. the basic
+                # gas turbine tutorial
+                # num_var = len(variable)
+                # for f in variable:
+                #     main_conn.fluid.val[f] = (1 - mass_fraction_sum) / num_var
 
             [c.build_fluid_data() for c in all_connections]
             for fluid in main_conn.fluid.is_var:
@@ -1992,8 +1994,6 @@ def solve(self, mode, init_path=None, design_path=None,
             logger.error(msg)
             return
 
-        self.postprocessing()
-
         if not self.progress:
             msg = (
                 'The solver does not seem to make any progress, aborting '
@@ -2005,6 +2005,8 @@ def solve(self, mode, init_path=None, design_path=None,
             logger.warning(msg)
             return
 
+        self.postprocessing()
+
         msg = 'Calculation complete.'
         logger.info(msg)
         return