Implement IRuleSubject for current and voltage sources

SpiceSharpBehavioral/Components/BehavioralSources/BehavioralCurrentSource/BehavioralCurrentSource.cs

@@ -1,14 +1,16 @@
 using SpiceSharp.Components.BehavioralComponents;
 using SpiceSharp.Attributes;
+using SpiceSharp.Validation;
+using System.Linq;
 
 namespace SpiceSharp.Components
 {
     /// <summary>
     /// A behavioral current source.
     /// </summary>
     /// <seealso cref="BehavioralComponent" />
-    [Pin(0, "I+"), Pin(1, "I-"), Connected]
-    public class BehavioralCurrentSource : BehavioralComponent
+    [Pin(0, "I+"), Pin(1, "I-"), IndependentSource, Connected]
+    public class BehavioralCurrentSource : BehavioralComponent, IRuleSubject
     {
         /// <summary>
         /// The behavioral current source base pin count
@@ -37,5 +39,14 @@ public BehavioralCurrentSource(string name, string pos, string neg, string expre
             Connect(pos, neg);
             Parameters.Expression = expression;
         }
+
+        /// <inheritdoc/>
+        void IRuleSubject.Apply(IRules rules)
+        {
+            var p = rules.GetParameterSet<ComponentRuleParameters>();
+            var nodes = Nodes.Select(name => p.Factory.GetSharedVariable(name)).ToArray();
+            foreach (var rule in rules.GetRules<IConductiveRule>())
+                rule.AddPath(this, ConductionTypes.None, nodes[0], nodes[1]);
+        }
     }
 }

SpiceSharpBehavioral/Components/BehavioralSources/BehavioralVoltageSource/BehavioralVoltageSource.cs

@@ -1,12 +1,16 @@
-using SpiceSharp.Components.BehavioralComponents;
+using SpiceSharp.Attributes;
+using SpiceSharp.Components.BehavioralComponents;
+using SpiceSharp.Validation;
+using System.Linq;
 
 namespace SpiceSharp.Components
 {
     /// <summary>
     /// A behavioral voltage source.
     /// </summary>
     /// <seealso cref="BehavioralComponent" />
-    public class BehavioralVoltageSource : BehavioralComponent
+    [Pin(0, "V+"), Pin(1, "V-"), VoltageDriver(0, 1), IndependentSource]
+    public class BehavioralVoltageSource : BehavioralComponent, IRuleSubject
     {
         /// <summary>
         /// The behavioral voltage source base pin count
@@ -35,5 +39,16 @@ public BehavioralVoltageSource(string name, string pos, string neg, string expre
             Connect(pos, neg);
             Parameters.Expression = expression;
         }
+
+        /// <inheritdoc/>
+        void IRuleSubject.Apply(IRules rules)
+        {
+            var p = rules.GetParameterSet<ComponentRuleParameters>();
+            var nodes = Nodes.Select(name => p.Factory.GetSharedVariable(name)).ToArray();
+            foreach (var rule in rules.GetRules<IConductiveRule>())
+                rule.AddPath(this, nodes[0], nodes[1]);
+            foreach (var rule in rules.GetRules<IAppliedVoltageRule>())
+                rule.Fix(this, nodes[0], nodes[1]);
+        }
     }
 }

SpiceSharpBehavioralTest/Components/BehavioralCurrentSourceTests.cs

@@ -66,6 +66,23 @@ public void When_UsedAsImpedanceOp_Expect_Reference(string expression, double dc
             op.Run(ckt);
         }
 
+        [Test]
+        public void When_DifferentialVoltage_Expect_Reference()
+        {
+            var ckt = new Circuit(
+                new VoltageSource("V1", "a", "0", new Sine(0, 1, 100)),
+                new VoltageSource("V2", "b", "0", new Sine(0, 2, 65)),
+                new BehavioralCurrentSource("I1", "0", "out", "V(a,b)/2"),
+                new Resistor("R1", "out", "0", 1));
+
+            var tran = new Transient("tran", 1e-6, 1e-3);
+            tran.ExportSimulationData += (sender, args) =>
+            {
+                Assert.AreEqual(0.5 * (args.GetVoltage("a") - args.GetVoltage("b")), args.GetVoltage("out"), 1e-12);
+            };
+            tran.Run(ckt);
+        }
+
         [Test]
         public void When_CapacitorTransient_Expect_Reference()
         {