powsybl · geofjamg · Dec 17, 2022 · Dec 16, 2022
diff --git a/src/main/java/com/powsybl/openloadflow/OpenLoadFlowParameters.java b/src/main/java/com/powsybl/openloadflow/OpenLoadFlowParameters.java
@@ -746,8 +746,8 @@ public static AcLoadFlowParameters createAcParameters(LoadFlowParameters paramet
 
     public static DcLoadFlowParameters createDcParameters(Network network, LoadFlowParameters parameters, OpenLoadFlowParameters parametersExt,
                                                           MatrixFactory matrixFactory, GraphConnectivityFactory<LfBus, LfBranch> connectivityFactory,
-                                                          boolean forcePhaseControlOffAndAddAngle1Var, boolean indexTerms) {
-        var dcParameters = createDcParameters(parameters, parametersExt, matrixFactory, connectivityFactory, forcePhaseControlOffAndAddAngle1Var, indexTerms);
+                                                          boolean forcePhaseControlOffAndAddAngle1Var) {
+        var dcParameters = createDcParameters(parameters, parametersExt, matrixFactory, connectivityFactory, forcePhaseControlOffAndAddAngle1Var);
         if (parameters.isReadSlackBus()) {
             dcParameters.getNetworkParameters().setSlackBusSelector(new NetworkSlackBusSelector(network, dcParameters.getNetworkParameters().getSlackBusSelector()));
         }
@@ -756,7 +756,7 @@ public static DcLoadFlowParameters createDcParameters(Network network, LoadFlowP
 
     public static DcLoadFlowParameters createDcParameters(LoadFlowParameters parameters, OpenLoadFlowParameters parametersExt,
                                                           MatrixFactory matrixFactory, GraphConnectivityFactory<LfBus, LfBranch> connectivityFactory,
-                                                          boolean forcePhaseControlOffAndAddAngle1Var, boolean indexTerms) {
+                                                          boolean forcePhaseControlOffAndAddAngle1Var) {
         SlackBusSelector slackBusSelector = SlackBusSelector.fromMode(parametersExt.getSlackBusSelectionMode(), parametersExt.getSlackBusesIds(), parametersExt.getPlausibleActivePowerLimit());
 
         var networkParameters = new LfNetworkParameters()
@@ -785,7 +785,6 @@ public static DcLoadFlowParameters createDcParameters(LoadFlowParameters paramet
                 .setSvcVoltageMonitoring(false);
 
         var equationSystemCreationParameters = new DcEquationSystemCreationParameters(true,
-                                                                                      indexTerms,
                                                                                       forcePhaseControlOffAndAddAngle1Var,
                                                                                       parameters.isDcUseTransformerRatio());
 

diff --git a/src/main/java/com/powsybl/openloadflow/OpenLoadFlowProvider.java b/src/main/java/com/powsybl/openloadflow/OpenLoadFlowProvider.java
@@ -169,7 +169,7 @@ private LoadFlowResult runDc(Network network, LoadFlowParameters parameters, Rep
         OpenLoadFlowParameters parametersExt = OpenLoadFlowParameters.get(parameters);
         OpenLoadFlowParameters.logDc(parameters, parametersExt);
 
-        var dcParameters = OpenLoadFlowParameters.createDcParameters(network, parameters, parametersExt, matrixFactory, connectivityFactory, forcePhaseControlOffAndAddAngle1Var, false);
+        var dcParameters = OpenLoadFlowParameters.createDcParameters(network, parameters, parametersExt, matrixFactory, connectivityFactory, forcePhaseControlOffAndAddAngle1Var);
 
         List<DcLoadFlowResult> results = DcLoadFlowEngine.run(network, new LfNetworkLoaderImpl(), dcParameters, reporter);
 

diff --git a/src/main/java/com/powsybl/openloadflow/ac/equations/AcEquationSystem.java b/src/main/java/com/powsybl/openloadflow/ac/equations/AcEquationSystem.java
@@ -763,7 +763,7 @@ public static EquationSystem<AcVariableType, AcEquationType> create(LfNetwork ne
         Objects.requireNonNull(network);
         Objects.requireNonNull(creationParameters);
 
-        EquationSystem<AcVariableType, AcEquationType> equationSystem = new EquationSystem<>(true);
+        EquationSystem<AcVariableType, AcEquationType> equationSystem = new EquationSystem<>();
 
         createBusesEquations(network, equationSystem, creationParameters);
         createBranchesEquations(network, equationSystem, creationParameters);

diff --git a/src/main/java/com/powsybl/openloadflow/dc/DcValueVoltageInitializer.java b/src/main/java/com/powsybl/openloadflow/dc/DcValueVoltageInitializer.java
@@ -47,7 +47,7 @@ public void prepare(LfNetwork network) {
         List<BusDcState> busStates = distributedSlack ? ElementState.save(network.getBuses(), BusDcState::save) : null;
 
         DcLoadFlowParameters parameters = new DcLoadFlowParameters(networkParameters,
-                                                                   new DcEquationSystemCreationParameters(false, false, false, useTransformerRatio),
+                                                                   new DcEquationSystemCreationParameters(false, false, useTransformerRatio),
                                                                    matrixFactory,
                                                                    distributedSlack,
                                                                    balanceType,

diff --git a/src/main/java/com/powsybl/openloadflow/dc/equations/DcEquationSystem.java b/src/main/java/com/powsybl/openloadflow/dc/equations/DcEquationSystem.java
@@ -120,7 +120,7 @@ private static void createBranches(LfNetwork network, EquationSystem<DcVariableT
 
     public static EquationSystem<DcVariableType, DcEquationType> create(LfNetwork network, DcEquationSystemCreationParameters creationParameters,
                                                                         boolean withListener) {
-        EquationSystem<DcVariableType, DcEquationType> equationSystem = new EquationSystem<>(creationParameters.isIndexTerms());
+        EquationSystem<DcVariableType, DcEquationType> equationSystem = new EquationSystem<>();
 
         createBuses(network, equationSystem);
         createBranches(network, equationSystem, creationParameters);

diff --git a/src/main/java/com/powsybl/openloadflow/dc/equations/DcEquationSystemCreationParameters.java b/src/main/java/com/powsybl/openloadflow/dc/equations/DcEquationSystemCreationParameters.java
@@ -13,8 +13,6 @@ public class DcEquationSystemCreationParameters {
 
     private final boolean updateFlows;
 
-    private final boolean indexTerms;
-
     /**
      * The purpose of this option is to add a constant a1 var to the equation system, to calculate sensitivity regarding
      * phase.
@@ -23,10 +21,9 @@ public class DcEquationSystemCreationParameters {
 
     private final boolean useTransformerRatio;
 
-    public DcEquationSystemCreationParameters(boolean updateFlows, boolean indexTerms, boolean forcePhaseControlOffAndAddAngle1Var,
+    public DcEquationSystemCreationParameters(boolean updateFlows, boolean forcePhaseControlOffAndAddAngle1Var,
                                               boolean useTransformerRatio) {
         this.updateFlows = updateFlows;
-        this.indexTerms = indexTerms;
         this.forcePhaseControlOffAndAddAngle1Var = forcePhaseControlOffAndAddAngle1Var;
         this.useTransformerRatio = useTransformerRatio;
     }
@@ -35,10 +32,6 @@ public boolean isUpdateFlows() {
         return updateFlows;
     }
 
-    public boolean isIndexTerms() {
-        return indexTerms;
-    }
-
     public boolean isForcePhaseControlOffAndAddAngle1Var() {
         return forcePhaseControlOffAndAddAngle1Var;
     }
@@ -51,7 +44,6 @@ public boolean isUseTransformerRatio() {
     public String toString() {
         return "DcEquationSystemCreationParameters(" +
                 "updateFlows=" + updateFlows +
-                ", indexTerms=" + indexTerms +
                 ", forcePhaseControlOffAndAddAngle1Var=" + forcePhaseControlOffAndAddAngle1Var +
                 ", useTransformerRatio=" + useTransformerRatio +
                 ')';

diff --git a/src/main/java/com/powsybl/openloadflow/equations/AbstractEquationTerm.java b/src/main/java/com/powsybl/openloadflow/equations/AbstractEquationTerm.java
@@ -8,6 +8,8 @@
 
 import com.powsybl.math.matrix.DenseMatrix;
 
+import java.util.Collections;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -36,6 +38,11 @@ public void setStateVector(StateVector sv) {
         this.sv = Objects.requireNonNull(sv);
     }
 
+    @Override
+    public List<EquationTerm<V, E>> getChildren() {
+        return Collections.emptyList();
+    }
+
     @Override
     public Equation<V, E> getEquation() {
         return equation;

diff --git a/src/main/java/com/powsybl/openloadflow/equations/EquationSystem.java b/src/main/java/com/powsybl/openloadflow/equations/EquationSystem.java
@@ -24,13 +24,11 @@
  */
 public class EquationSystem<V extends Enum<V> & Quantity, E extends Enum<E> & Quantity> {
 
-    private final boolean indexTerms;
-
     private final Map<Pair<Integer, E>, Equation<V, E>> equations = new HashMap<>();
 
     private final Map<Pair<ElementType, Integer>, List<Equation<V, E>>> equationsByElement = new HashMap<>();
 
-    private final Map<Pair<ElementType, Integer>, List<EquationTerm<V, E>>> equationTermsByElement = new HashMap<>();
+    private Map<Pair<ElementType, Integer>, List<EquationTerm<V, E>>> equationTermsByElement;
 
     private final List<EquationSystemListener<V, E>> listeners = new ArrayList<>();
 
@@ -41,16 +39,11 @@ public class EquationSystem<V extends Enum<V> & Quantity, E extends Enum<E> & Qu
     private final EquationSystemIndex<V, E> index;
 
     public EquationSystem() {
-        this(false);
-    }
-
-    public EquationSystem(boolean indexTerms) {
-        this(new VariableSet<>(), indexTerms);
+        this(new VariableSet<>());
     }
 
-    public EquationSystem(VariableSet<V> variableSet, boolean indexTerms) {
+    public EquationSystem(VariableSet<V> variableSet) {
         this.variableSet = Objects.requireNonNull(variableSet);
-        this.indexTerms = indexTerms;
         index = new EquationSystemIndex<>(this);
     }
 
@@ -74,21 +67,38 @@ public Collection<Equation<V, E>> getEquations() {
         return equations.values();
     }
 
-    void addEquationTerm(EquationTerm<V, E> equationTerm) {
-        if (indexTerms) {
-            Objects.requireNonNull(equationTerm);
-            Pair<ElementType, Integer> element = Pair.of(equationTerm.getElementType(), equationTerm.getElementNum());
-            equationTermsByElement.computeIfAbsent(element, k -> new ArrayList<>())
-                    .add(equationTerm);
+    private void indexTerm(EquationTerm<V, E> equationTerm) {
+        if (equationTermsByElement != null) {
+            if (equationTerm.getElementType() != null && equationTerm.getElementNum() != -1) {
+                Pair<ElementType, Integer> element = Pair.of(equationTerm.getElementType(), equationTerm.getElementNum());
+                equationTermsByElement.computeIfAbsent(element, k -> new ArrayList<>())
+                        .add(equationTerm);
+            }
+            for (EquationTerm<V, E> child : equationTerm.getChildren()) {
+                indexTerm(child);
+            }
         }
+    }
+
+    private void indexAllTerms() {
+        if (equationTermsByElement == null) {
+            equationTermsByElement = new HashMap<>();
+            for (var equation : equations.values()) {
+                for (var term : equation.getTerms()) {
+                    indexTerm(term);
+                }
+            }
+        }
+    }
+
+    void addEquationTerm(EquationTerm<V, E> equationTerm) {
+        indexTerm(equationTerm);
         attach(equationTerm);
     }
 
     public List<EquationTerm<V, E>> getEquationTerms(ElementType elementType, int elementNum) {
-        if (!indexTerms) {
-            throw new PowsyblException("Equations terms have not been indexed");
-        }
         Objects.requireNonNull(elementType);
+        indexAllTerms();
         Pair<ElementType, Integer> element = Pair.of(elementType, elementNum);
         return equationTermsByElement.getOrDefault(element, Collections.emptyList());
     }

diff --git a/src/main/java/com/powsybl/openloadflow/equations/EquationTerm.java b/src/main/java/com/powsybl/openloadflow/equations/EquationTerm.java
@@ -12,6 +12,7 @@
 
 import java.io.IOException;
 import java.io.Writer;
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.DoubleSupplier;
@@ -39,6 +40,11 @@ class MultiplyByScalarEquationTerm<V extends Enum<V> & Quantity, E extends Enum<
             term.setSelf(this);
         }
 
+        @Override
+        public List<EquationTerm<V, E>> getChildren() {
+            return Collections.singletonList(term);
+        }
+
         @Override
         public Equation<V, E> getEquation() {
             return term.getEquation();
@@ -66,12 +72,12 @@ public void setSelf(EquationTerm<V, E> self) {
 
         @Override
         public ElementType getElementType() {
-            return term.getElementType();
+            return null;
         }
 
         @Override
         public int getElementNum() {
-            return term.getElementNum();
+            return -1;
         }
 
         @Override
@@ -125,53 +131,7 @@ static <V extends Enum<V> & Quantity, E extends Enum<E> & Quantity> EquationTerm
         return new MultiplyByScalarEquationTerm<>(term, scalar);
     }
 
-    class VariableEquationTerm<V extends Enum<V> & Quantity, E extends Enum<E> & Quantity> extends AbstractEquationTerm<V, E> {
-
-        private final List<Variable<V>> variables;
-
-        VariableEquationTerm(Variable<V> variable) {
-            this.variables = List.of(Objects.requireNonNull(variable));
-        }
-
-        private Variable<V> getVariable() {
-            return variables.get(0);
-        }
-
-        @Override
-        public ElementType getElementType() {
-            return getVariable().getType().getElementType();
-        }
-
-        @Override
-        public int getElementNum() {
-            return getVariable().getElementNum();
-        }
-
-        @Override
-        public List<Variable<V>> getVariables() {
-            return variables;
-        }
-
-        @Override
-        public double eval() {
-            return sv.get(getVariable().getRow());
-        }
-
-        @Override
-        public double der(Variable<V> variable) {
-            return 1;
-        }
-
-        @Override
-        public double calculateSensi(DenseMatrix dx, int column) {
-            return dx.get(getVariable().getRow(), column);
-        }
-
-        @Override
-        public void write(Writer writer) throws IOException {
-            getVariable().write(writer);
-        }
-    }
+    List<EquationTerm<V, E>> getChildren();
 
     Equation<V, E> getEquation();
 

diff --git a/src/main/java/com/powsybl/openloadflow/equations/Variable.java b/src/main/java/com/powsybl/openloadflow/equations/Variable.java
@@ -76,7 +76,7 @@ public void write(Writer writer) throws IOException {
     }
 
     public <E extends Enum<E> & Quantity> EquationTerm<V, E> createTerm() {
-        return new EquationTerm.VariableEquationTerm<>(this);
+        return new VariableEquationTerm<>(this);
     }
 
     @Override

diff --git a/src/main/java/com/powsybl/openloadflow/equations/VariableEquationTerm.java b/src/main/java/com/powsybl/openloadflow/equations/VariableEquationTerm.java
@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) 2022, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package com.powsybl.openloadflow.equations;
+
+import com.powsybl.math.matrix.DenseMatrix;
+import com.powsybl.openloadflow.network.ElementType;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * @author Geoffroy Jamgotchian <geoffroy.jamgotchian at rte-france.com>
+ */
+public class VariableEquationTerm<V extends Enum<V> & Quantity, E extends Enum<E> & Quantity> extends AbstractEquationTerm<V, E> {
+
+    private final List<Variable<V>> variables;
+
+    public VariableEquationTerm(Variable<V> variable) {
+        this.variables = List.of(Objects.requireNonNull(variable));
+    }
+
+    private Variable<V> getVariable() {
+        return variables.get(0);
+    }
+
+    @Override
+    public ElementType getElementType() {
+        return getVariable().getType().getElementType();
+    }
+
+    @Override
+    public int getElementNum() {
+        return getVariable().getElementNum();
+    }
+
+    @Override
+    public List<Variable<V>> getVariables() {
+        return variables;
+    }
+
+    @Override
+    public double eval() {
+        return sv.get(getVariable().getRow());
+    }
+
+    @Override
+    public double der(Variable<V> variable) {
+        return 1;
+    }
+
+    @Override
+    public double calculateSensi(DenseMatrix dx, int column) {
+        return dx.get(getVariable().getRow(), column);
+    }
+
+    @Override
+    public void write(Writer writer) throws IOException {
+        getVariable().write(writer);
+    }
+}
diff --git a/src/main/java/com/powsybl/openloadflow/sa/DcSecurityAnalysis.java b/src/main/java/com/powsybl/openloadflow/sa/DcSecurityAnalysis.java
@@ -228,7 +228,7 @@ private List<OperatorStrategyResult> createOperatorStrategyResults(DcSecurityAna
         boolean breakers = !(allSwitchesToOpen.isEmpty() && allSwitchesToClose.isEmpty());
 
         var dcParameters = OpenLoadFlowParameters.createDcParameters(network, context.getParameters().getLoadFlowParameters(),
-                parametersExt, matrixFactory, connectivityFactory, false, true);
+                parametersExt, matrixFactory, connectivityFactory, false);
         dcParameters.getNetworkParameters().setBreakers(breakers);
 
         try (LfNetworkList lfNetworks = Networks.load(network, dcParameters.getNetworkParameters(), allSwitchesToOpen, allSwitchesToClose, Reporter.NO_OP)) {

diff --git a/src/main/java/com/powsybl/openloadflow/sensi/DcSensitivityAnalysis.java b/src/main/java/com/powsybl/openloadflow/sensi/DcSensitivityAnalysis.java
@@ -215,7 +215,6 @@ private JacobianMatrix<DcVariableType, DcEquationType> createJacobianMatrix(LfNe
     private static DcLoadFlowParameters createDcLoadFlowParameters(LfNetworkParameters networkParameters, MatrixFactory matrixFactory,
                                                                    LoadFlowParameters lfParameters) {
         var equationSystemCreationParameters = new DcEquationSystemCreationParameters(true,
-                true,
                 true,
                 lfParameters.isDcUseTransformerRatio());