Refine time index of Flows

docs/whatsnew/v0-5-3.rst

@@ -35,6 +35,7 @@ Other changes
 
 * Unified (usage) documentation for `OffsetConverter`
 * Remove approach to model cellular systems (was more confusing than it helped)
+* Refine indexing of flows (period index was not needed).
 
 Known issues
 ############

examples/flexible_modelling/add_constraints.py

@@ -123,26 +123,26 @@ def run_add_constraints_example(solver="cbc", nologg=False):
     # add the sub-model to the oemof Model instance
     om.add_component("MyBlock", myblock)
 
-    def _inflow_share_rule(m, s, e, p, t):
+    def _inflow_share_rule(m, s, e, t):
         """pyomo rule definition: Here we can use all objects from the block or
         the om object, in this case we don't need anything from the block
         except the newly defined set MYFLOWS.
         """
-        expr = om.flow[s, e, p, t] >= om.flows[s, e].outflow_share[t] * sum(
-            om.flow[i, o, p, t] for (i, o) in om.FLOWS if o == e
+        expr = om.flow[s, e, t] >= om.flows[s, e].outflow_share[t] * sum(
+            om.flow[i, o, t] for (i, o) in om.FLOWS if o == e
         )
         return expr
 
     myblock.inflow_share = po.Constraint(
-        myblock.MYFLOWS, om.TIMEINDEX, rule=_inflow_share_rule
+        myblock.MYFLOWS, om.TIMESTEPS, rule=_inflow_share_rule
     )
     # add emission constraint
     myblock.emission_constr = po.Constraint(
         expr=(
             sum(
-                om.flow[i, o, p, t]
+                om.flow[i, o, t]
                 for (i, o) in myblock.COMMODITYFLOWS
-                for p, t in om.TIMEINDEX
+                for t in om.TIMESTEPS
             )
             <= emission_limit
         )

src/oemof/solph/_models.py

@@ -461,33 +461,33 @@ def _add_parent_block_sets(self):
     def _add_parent_block_variables(self):
         """Add the parent block variables, which is the `flow` variable,
         indexed by FLOWS and TIMEINDEX."""
-        self.flow = po.Var(self.FLOWS, self.TIMEINDEX, within=po.Reals)
+        self.flow = po.Var(self.FLOWS, self.TIMESTEPS, within=po.Reals)
 
         for o, i in self.FLOWS:
             if self.flows[o, i].nominal_value is not None:
                 if self.flows[o, i].fix[self.TIMESTEPS.at(1)] is not None:
-                    for p, t in self.TIMEINDEX:
-                        self.flow[o, i, p, t].value = (
+                    for t in self.TIMESTEPS:
+                        self.flow[o, i, t].value = (
                             self.flows[o, i].fix[t]
                             * self.flows[o, i].nominal_value
                         )
-                        self.flow[o, i, p, t].fix()
+                        self.flow[o, i, t].fix()
                 else:
-                    for p, t in self.TIMEINDEX:
-                        self.flow[o, i, p, t].setub(
+                    for t in self.TIMESTEPS:
+                        self.flow[o, i, t].setub(
                             self.flows[o, i].max[t]
                             * self.flows[o, i].nominal_value
                         )
                     if not self.flows[o, i].nonconvex:
-                        for p, t in self.TIMEINDEX:
-                            self.flow[o, i, p, t].setlb(
+                        for t in self.TIMESTEPS:
+                            self.flow[o, i, t].setlb(
                                 self.flows[o, i].min[t]
                                 * self.flows[o, i].nominal_value
                             )
                     elif (o, i) in self.UNIDIRECTIONAL_FLOWS:
-                        for p, t in self.TIMEINDEX:
-                            self.flow[o, i, p, t].setlb(0)
+                        for t in self.TIMESTEPS:
+                            self.flow[o, i, t].setlb(0)
             else:
                 if (o, i) in self.UNIDIRECTIONAL_FLOWS:
-                    for p, t in self.TIMEINDEX:
-                        self.flow[o, i, p, t].setlb(0)
+                    for t in self.TIMESTEPS:
+                        self.flow[o, i, t].setlb(0)

src/oemof/solph/buses/_bus.py

@@ -78,9 +78,9 @@ class BusBlock(ScalarBlock):
 
      Bus balance: `om.Bus.balance[i, o, t]`
        .. math::
-         \sum_{i \in INPUTS(n)} P_{i}(p, t) =
-         \sum_{o \in OUTPUTS(n)} P_{o}(p, t), \\
-         \forall p, t \in \textrm{TIMEINDEX}, \\
+         \sum_{i \in INPUTS(n)} P_{i}(t) =
+         \sum_{o \in OUTPUTS(n)} P_{o}(t), \\
+         \forall t \in \textrm{TIMESTEPS}, \\
          \forall i \in \textrm{INPUTS}, \\
          \forall o \in \textrm{OUTPUTS}
 
@@ -89,17 +89,17 @@ class BusBlock(ScalarBlock):
      output of the Bus object.
 
      The index :math:`n` is the index for the Bus node itself. Therefore,
-     a :math:`flow[i, n, p, t]` is a flow from the Component i to the Bus n at
+     a :math:`flow[i, n, t]` is a flow from the Component i to the Bus n at
      time index p, t.
 
-     ======================  ============================  ====================
-     symbol                  attribute                     explanation
-     ======================  ============================  ====================
-     :math:`P_{i}(p, t)`     `flow[i, n, p, t]`            Bus, inflow
+     ======================  =========================  ====================
+     symbol                  attribute                  explanation
+     ======================  =========================  ====================
+     :math:`P_{i}(p, t)`     `flow[i, n, t]`            Bus, inflow
 
-     :math:`P_{o}(p, t)`     `flow[n, o, p, t]`            Bus, outflow
+     :math:`P_{o}(p, t)`     `flow[n, o, t]`            Bus, outflow
 
-     ======================  ============================  ====================
+     ======================  =========================  ====================
      """
 
     def __init__(self, *args, **kwargs):
@@ -126,14 +126,14 @@ def _create(self, group=None):
             outs[n] = [o for o in n.outputs]
 
         def _busbalance_rule(block):
-            for p, t in m.TIMEINDEX:
+            for t in m.TIMESTEPS:
                 for g in group:
-                    lhs = sum(m.flow[i, g, p, t] for i in ins[g])
-                    rhs = sum(m.flow[g, o, p, t] for o in outs[g])
+                    lhs = sum(m.flow[i, g, t] for i in ins[g])
+                    rhs = sum(m.flow[g, o, t] for o in outs[g])
                     expr = lhs == rhs
                     # no inflows no outflows yield: 0 == 0 which is True
                     if expr is not True:
-                        block.balance.add((g, p, t), expr)
+                        block.balance.add((g, t), expr)
 
-        self.balance = Constraint(group, m.TIMEINDEX, noruleinit=True)
+        self.balance = Constraint(group, m.TIMESTEPS, noruleinit=True)
         self.balance_build = BuildAction(rule=_busbalance_rule)

src/oemof/solph/components/_converter.py

@@ -181,9 +181,9 @@ class ConverterBlock(ScalarBlock):
 
     Linear relation :attr:`om.ConverterBlock.relation[i,o,t]`
         .. math::
-            P_{i}(p, t) \cdot \eta_{o}(t) =
-            P_{o}(p, t) \cdot \eta_{i}(t), \\
-            \forall p, t \in \textrm{TIMEINDEX}, \\
+            P_{i}(t) \cdot \eta_{o}(t) =
+            P_{o}(t) \cdot \eta_{i}(t), \\
+            \forall t \in \textrm{TIMESTEPS}, \\
             \forall n \in \textrm{CONVERTERS}, \\
             \forall i \in \textrm{INPUTS}, \\
             \forall o \in \textrm{OUTPUTS}
@@ -196,15 +196,15 @@ class ConverterBlock(ScalarBlock):
     constraints.
 
     The index :math: n is the index for the Transformer node itself. Therefore,
-    a `flow[i, n, p, t]` is a flow from the Bus i to the Transformer n at
+    a `flow[i, n, t]` is a flow from the Bus i to the Transformer n at
     time index p, t.
 
     ======================  ============================  ====================
     symbol                  attribute                     explanation
     ======================  ============================  ====================
-    :math:`P_{i,n}(p, t)`   `flow[i, n, p, t]`            Converter, inflow
+    :math:`P_{i,n}(p, t)`   `flow[i, n, t]`               Converter, inflow
 
-    :math:`P_{n,o}(p, t)`   `flow[n, o, p, t]`            Converter, outflow
+    :math:`P_{n,o}(p, t)`   `flow[n, o, t]`               Converter, outflow
 
     :math:`\eta_{i}(t)`     `conversion_factor[i, n, t]`  Inflow, efficiency
 
@@ -243,8 +243,8 @@ def _create(self, group=None):
 
         self.relation = Constraint(
             [
-                (n, i, o, p, t)
-                for p, t in m.TIMEINDEX
+                (n, i, o, t)
+                for t in m.TIMESTEPS
                 for n in group
                 for o in out_flows[n]
                 for i in in_flows[n]
@@ -253,17 +253,17 @@ def _create(self, group=None):
         )
 
         def _input_output_relation(block):
-            for p, t in m.TIMEINDEX:
+            for t in m.TIMESTEPS:
                 for n in group:
                     for o in out_flows[n]:
                         for i in in_flows[n]:
                             try:
                                 lhs = (
-                                    m.flow[i, n, p, t]
+                                    m.flow[i, n, t]
                                     * n.conversion_factors[o][t]
                                 )
                                 rhs = (
-                                    m.flow[n, o, p, t]
+                                    m.flow[n, o, t]
                                     * n.conversion_factors[i][t]
                                 )
                             except ValueError:
@@ -273,6 +273,6 @@ def _input_output_relation(block):
                                         n.label, o.label
                                     ),
                                 )
-                            block.relation.add((n, i, o, p, t), (lhs == rhs))
+                            block.relation.add((n, i, o, t), (lhs == rhs))
 
         self.relation_build = BuildAction(rule=_input_output_relation)

src/oemof/solph/components/_extraction_turbine_chp.py

@@ -105,17 +105,17 @@ class ExtractionTurbineCHPBlock(ScalarBlock):
 
     * :math:`\dot H_{Fuel}`
 
-        Fuel input flow, represented in code as `flow[i, n, p, t]`
+        Fuel input flow, represented in code as `flow[i, n, t]`
 
     * :math:`P_{el}`
 
         Electric power outflow, represented in code as
-        `flow[n, main_output, p, t]`
+        `flow[n, main_output, t]`
 
     * :math:`\dot Q_{th}`
 
         Thermal output flow, represented in code as
-        `flow[n, tapped_output, p, t]`
+        `flow[n, tapped_output, t]`
 
     **Parameters**
 
@@ -242,36 +242,36 @@ def _create(self, group=None):
 
         def _input_output_relation_rule(block):
             """Connection between input, main output and tapped output."""
-            for p, t in m.TIMEINDEX:
+            for t in m.TIMESTEPS:
                 for g in group:
-                    lhs = m.flow[g.inflow, g, p, t]
+                    lhs = m.flow[g.inflow, g, t]
                     rhs = (
-                        m.flow[g, g.main_output, p, t]
-                        + m.flow[g, g.tapped_output, p, t]
+                        m.flow[g, g.main_output, t]
+                        + m.flow[g, g.tapped_output, t]
                         * g.main_flow_loss_index[t]
                     ) / g.conversion_factor_full_condensation_sq[t]
-                    block.input_output_relation.add((g, p, t), (lhs == rhs))
+                    block.input_output_relation.add((g, t), (lhs == rhs))
 
         self.input_output_relation = Constraint(
-            group, m.TIMEINDEX, noruleinit=True
+            group, m.TIMESTEPS, noruleinit=True
         )
         self.input_output_relation_build = BuildAction(
             rule=_input_output_relation_rule
         )
 
         def _out_flow_relation_rule(block):
             """Relation between main and tapped output in full chp mode."""
-            for p, t in m.TIMEINDEX:
+            for t in m.TIMESTEPS:
                 for g in group:
-                    lhs = m.flow[g, g.main_output, p, t]
+                    lhs = m.flow[g, g.main_output, t]
                     rhs = (
-                        m.flow[g, g.tapped_output, p, t]
+                        m.flow[g, g.tapped_output, t]
                         * g.flow_relation_index[t]
                     )
-                    block.out_flow_relation.add((g, p, t), (lhs >= rhs))
+                    block.out_flow_relation.add((g, t), (lhs >= rhs))
 
         self.out_flow_relation = Constraint(
-            group, m.TIMEINDEX, noruleinit=True
+            group, m.TIMESTEPS, noruleinit=True
         )
         self.out_flow_relation_build = BuildAction(
             rule=_out_flow_relation_rule

src/oemof/solph/components/_generic_chp.py

@@ -338,37 +338,37 @@ def _create(self, group=None):
         self.Y = Var(self.GENERICCHPS, m.TIMESTEPS, within=Binary)
 
         # constraint rules
-        def _H_flow_rule(block, n, p, t):
+        def _H_flow_rule(block, n, t):
             """Link fuel consumption to component inflow."""
             expr = 0
             expr += self.H_F[n, t]
-            expr += -m.flow[list(n.fuel_input.keys())[0], n, p, t]
+            expr += -m.flow[list(n.fuel_input.keys())[0], n, t]
             return expr == 0
 
         self.H_flow = Constraint(
-            self.GENERICCHPS, m.TIMEINDEX, rule=_H_flow_rule
+            self.GENERICCHPS, m.TIMESTEPS, rule=_H_flow_rule
         )
 
-        def _Q_flow_rule(block, n, p, t):
+        def _Q_flow_rule(block, n, t):
             """Link heat flow to component outflow."""
             expr = 0
             expr += self.Q[n, t]
-            expr += -m.flow[n, list(n.heat_output.keys())[0], p, t]
+            expr += -m.flow[n, list(n.heat_output.keys())[0], t]
             return expr == 0
 
         self.Q_flow = Constraint(
-            self.GENERICCHPS, m.TIMEINDEX, rule=_Q_flow_rule
+            self.GENERICCHPS, m.TIMESTEPS, rule=_Q_flow_rule
         )
 
-        def _P_flow_rule(block, n, p, t):
+        def _P_flow_rule(block, n, t):
             """Link power flow to component outflow."""
             expr = 0
             expr += self.P[n, t]
-            expr += -m.flow[n, list(n.electrical_output.keys())[0], p, t]
+            expr += -m.flow[n, list(n.electrical_output.keys())[0], t]
             return expr == 0
 
         self.P_flow = Constraint(
-            self.GENERICCHPS, m.TIMEINDEX, rule=_P_flow_rule
+            self.GENERICCHPS, m.TIMESTEPS, rule=_P_flow_rule
         )
 
         def _H_F_1_rule(block, n, t):