more robust systems

biosteam/_system.py

@@ -456,14 +456,15 @@ def find_blowdown_recycle(facilities):
         if isa(i, bst.BlowdownMixer): return i.outs[0]
 
 def find_recycles(path):
+    all_units = set(path)
     past_outlets = set()
-    recycles = []
+    recycles = set()
     for i in path:
         for s in i.ins:
-            if s in past_outlets or s.isfeed(): continue
-            recycles.append(s)
+            if s in past_outlets or s.source not in all_units: continue
+            recycles.add(s)
         past_outlets.update(i.outs)
-    return recycles
+    return list(recycles)
 
 # %% LCA
 
@@ -1676,7 +1677,7 @@ def flatten(self):
                     break
             if stop: break
         self._path = tuple(path)
-        self._recycle = find_recycles(self._path)
+        self._recycle = find_recycles(path)
 
     def to_unit_group(self, name: Optional[str]=None):
         """Return a UnitGroup object of all units within the system."""
@@ -3309,7 +3310,8 @@ def _to_network(self):
         path = [(i._to_network() if isa(i, System) else i) for i in self._path]
         network = Network.__new__(Network)
         network.path = path
-        network.recycle = self._recycle
+        recycle = self._recycle
+        network.recycle = set(recycle) if isinstance(recycle, list) else recycle
         network.units = set(self.unit_path)
         return network
 

biosteam/_unit.py

@@ -881,10 +881,11 @@ def _check_run(self):
                 self.baseline_purchase_costs, 
                 self.purchase_costs, 
                 self.installed_costs]):
-            raise UnitInheritanceError(
+            warn(
                f'`{type(self).__name__}._run` method added unit results '
                 '(e.g., purchase costs, heat and power utilities); unit results '
-                'should only be added in `_design` or `_cost` methods'
+                'should only be added in `_design` or `_cost` methods',
+                RuntimeWarning
             )
 
     def materialize_connections(self):

biosteam/evaluation/_feature.py

@@ -99,11 +99,7 @@ def describe(self, number_format='.3g', distribution=True, bounds=True) -> str:
         name = self.name
         if self.element:
             name = self.element_name + ' - ' + name
-        if self.units:
-            units = (' [' + str(self.units) + ']')
-        else:
-            units = ''
-        description = name + units
+        description = name
         if distribution:
             if getattr(self, 'distribution', None):
                 dist_name = type(self.distribution).__name__
@@ -119,11 +115,17 @@ def describe(self, number_format='.3g', distribution=True, bounds=True) -> str:
                 lb, ub = bounds
                 values = ', '.join([format(i, number_format)
                                     for i in (lb, baseline, ub)])
-                description += f' ({values})'
+                if self.units:
+                    description += f' ({values} {str(self.units)})'
+                else:
+                    description += f' ({values})'
         if description:
             first_letter = description[0]
             if first_letter.islower(): 
                 description = first_letter.upper() + description[1:]
+        if not bounds and self.units:
+            units = (' [' + str(self.units) + ']')
+            description += units
         return description
 
 

biosteam/evaluation/_model.py

@@ -713,11 +713,11 @@ def single_point_sensitivity(self,
         relative_error = error / np.maximum.reduce([np.abs(baseline_1[index]), np.abs(baseline_2[index])])
         for i, idx in enumerate(index):
             if relative_error[i] > etol:
-                raise RuntimeError(
+                print(RuntimeError(
                     f"inconsistent model; {metrics[idx]} has a value of "
                     f"{baseline_1[idx]} before evaluating sensitivity and "
                     f"{baseline_2[idx]} after"
-                )
+                ))
         baseline = 0.5 * (baseline_1 + baseline_2)
         if array:
             return baseline, values_lb, values_ub

biosteam/facilities/hxn/_heat_exchanger_network.py

@@ -215,7 +215,7 @@ def _cost(self):
                         unit = i.unit
                         if s_out: unit.ins[i.index] = s_out
                         s_out = unit.outs[i.index]
-                self.HXN_sys = sys = bst.System.from_units(None, all_units)
+                self.HXN_sys = sys = bst.System(ID=None, path=all_units)
                 sys.set_tolerance(method='fixedpoint', subsystems=True)
 
             original_purchase_costs = [hx.purchase_cost for hx in hxs]

tests/test_autogenerated_system.py

@@ -395,12 +395,10 @@ def test_two_recycle_loops_with_complete_overlap():
          P3,
          Network(
             [M1,
-             Network(
-                 [M2,
-                  S2],
-                 recycle=inner_recycle),
+             M2,
+             S2,
              S1],
-            recycle=recycle)])
+            recycle={recycle, inner_recycle})])
     assert network == actual_network
     recycle_loop_sys.simulate()
     x_nested_solution = np.vstack([recycle.mol, inner_recycle.mol])
@@ -438,31 +436,16 @@ def test_two_recycle_loops_with_partial_overlap():
          P3,
          Network(
             [M1,
-             Network(
-                 [M2,
-                  S2,
-                  S3],
-                 recycle=inner_recycle),
-             S1],
-            recycle=recycle)])
-    actual_network_alternative = Network(
-        [P1,
-         P2,
-         P3,
-         Network(
-            [Network(
-                [M1,
-                 M2,
-                 S2,
-                 S1],
-                recycle=S1-1),
+             M2,
+             S2,
+             S1,
              S3],
-            recycle=S3-1)])
-    assert network == actual_network or network == actual_network_alternative
+            recycle={recycle, inner_recycle})])
+    assert network == actual_network
     recycle_loop_sys.simulate()
     x_nested_solution = np.vstack([recycle.mol, inner_recycle.mol])
     recycle_loop_sys.flatten()
-    assert recycle_loop_sys.path == (P1, P2, P3, M1, M2, S2, S3, S1)
+    assert recycle_loop_sys.path == (P1, P2, P3, M1, M2, S2, S1, S3)
     recycle_loop_sys.empty_recycles()
     recycle_loop_sys.simulate()
     x_flat_solution = np.vstack([recycle.mol, inner_recycle.mol])
@@ -607,30 +590,25 @@ def test_nested_recycle_loops():
          Network(
             [M1,
              P2,
-             Network(
-                [H1,
-                 M3],
-                recycle=M3-0),
+             H1,
+             M3,
+             H1,
              P4,
-             Network(
-                [M4,
-                 M5,
-                 Network(
-                    [H2,
-                     M6,
-                     S1],
-                    recycle=S1-0),
-                 S2,
-                 P8,
-                 S3,
-                 Network(
-                    [M7,
-                     S4,
-                     H3],
-                    recycle=H3-0)],
-                recycle=H3-1),
+             M4,
+             M5,
+             H2,
+             M6,
+             S1,
+             H2,
+             S2,
+             H3,
+             P8,
+             S3,
+             M7,
+             S4,
+             H3,
              S5],
-            recycle=S5-1),
+            recycle={S5-1, S4-1}),
          M8])
     assert network == actual_network 
     x_nested_solution = np.vstack([i.mol for i in recycles])