Propgage symmetry when adding otbital integral terms to Hamiltonian.

Chemistry.sln

@@ -26,6 +26,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "BroombridgeExamples", "Broo
 	ProjectSection(SolutionItems) = preProject
 		Chemistry\tests\TestData\Broombridge\broombridge_v0.1.yaml = Chemistry\tests\TestData\Broombridge\broombridge_v0.1.yaml
 		Chemistry\tests\TestData\Broombridge\broombridge_v0.2.yaml = Chemistry\tests\TestData\Broombridge\broombridge_v0.2.yaml
+		Chemistry\tests\TestData\Broombridge\H2O-6_fourfold_v0.3.yaml = Chemistry\tests\TestData\Broombridge\H2O-6_fourfold_v0.3.yaml
+		Chemistry\tests\TestData\Broombridge\H2O-6_trivial_v0.3.yaml = Chemistry\tests\TestData\Broombridge\H2O-6_trivial_v0.3.yaml
 		Chemistry\tests\TestData\Broombridge\hydrogen_0.1.yaml = Chemistry\tests\TestData\Broombridge\hydrogen_0.1.yaml
 		Chemistry\tests\TestData\Broombridge\hydrogen_0.2.yaml = Chemistry\tests\TestData\Broombridge\hydrogen_0.2.yaml
 		Chemistry\tests\TestData\Broombridge\LiH_0.1.yaml = Chemistry\tests\TestData\Broombridge\LiH_0.1.yaml

Chemistry/src/DataModel/OrbitalIntegral/OrbitalIntegralExtensions.cs

@@ -48,7 +48,6 @@ namespace Microsoft.Quantum.Chemistry.OrbitalIntegrals
             return hamiltonian;
         }
 
-
         /// <summary>
         /// Creates all fermion terms generated by all symmetries of an orbital integral.
         /// </summary>

Chemistry/src/DataModel/OrbitalIntegral/OrbitalIntegralHamiltonian.cs

@@ -32,7 +32,7 @@ namespace Microsoft.Quantum.Chemistry.OrbitalIntegrals
         /// <param name="orbitalIntegral">Orbital integral to add to Hamiltonian.</param>
         public void Add(OrbitalIntegral orbitalIntegral)
         {
-            Add(new OrbitalIntegral(orbitalIntegral.OrbitalIndices), orbitalIntegral.Coefficient);
+            Add(new OrbitalIntegral(orbitalIntegral.OrbitalIndices, symmetry: orbitalIntegral.Symmetry), orbitalIntegral.Coefficient);
         }
 
         /// <summary>

Chemistry/tests/DataModelTests/DataModelTests.csproj

@@ -42,7 +42,7 @@
 
   <!-- Serialization test data -->
   <ItemGroup>
-    <!-- Broombridge v0.1 and v0.2 examples -->
+    <!-- Broombridge v0.1, v0.2, and v0.3 examples -->
     <None Include="..\TestData\Broombridge\broombridge_v0.1.yaml" Link="Broombridge\broombridge_v0.1.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
@@ -52,6 +52,12 @@
     <None Include="..\TestData\Broombridge\LiH_0.1.yaml" Link="Broombridge\LiH_0.1.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Include="..\TestData\Broombridge\H2O-6_trivial_v0.3.yaml" Link="Broombridge\H2O-6_trivial_v0.3.yaml">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Include="..\TestData\Broombridge\H2O-6_fourfold_v0.3.yaml" Link="Broombridge\H2O-6_fourfold_v0.3.yaml">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     
     <!-- FCIDUMP examples -->
     <None Include="..\TestData\FciDump\h2_anorccmb.fcidump" Link="FciDump\h2_anorccmb.fcidump">

Chemistry/tests/DataModelTests/OrbitalIntegralTests/OrbitalIntegralTests.cs

@@ -63,5 +63,43 @@ namespace Microsoft.Quantum.Chemistry.Tests
             Assert.True(orb0 == orb1);
             Assert.False(orb0 == orb2);
         }
+
+        // Test fourfold symmetry
+        [Theory]
+        [InlineData(0, 0, 0, 0, 1)]
+        [InlineData(0, 0, 0, 1, 4)]
+        [InlineData(0, 0, 1, 0, 4)]
+        [InlineData(0, 1, 0, 0, 4)]
+        [InlineData(1, 0, 0, 0, 4)]
+        [InlineData(1, 1, 0, 0, 2)]
+        [InlineData(0, 1, 1, 0, 2)]
+        [InlineData(0, 0, 1, 2, 4)]
+        [InlineData(0, 1, 2, 0, 4)]
+        [InlineData(0, 1, 2, 3, 4)]
+        public void OrbitalIntegralEnumerateOrbitalSymmetriesFourfoldTest(int i, int j, int k, int l, int elements)
+        {
+            OrbitalIntegral orbitalIntegral = new OrbitalIntegral(new int[] { i, j, k, l }, 0.0, OrbitalIntegral.PermutationSymmetry.Fourfold);
+            var orbitalIntegrals = orbitalIntegral.EnumerateOrbitalSymmetries();
+            Assert.Equal(elements, orbitalIntegrals.Length);
+        }
+
+        // Test trivial symmetry
+        [Theory]
+        [InlineData(0, 0, 0, 0, 1)]
+        [InlineData(0, 0, 0, 1, 1)]
+        [InlineData(0, 0, 1, 0, 1)]
+        [InlineData(0, 1, 0, 0, 1)]
+        [InlineData(1, 0, 0, 0, 1)]
+        [InlineData(1, 1, 0, 0, 1)]
+        [InlineData(0, 1, 1, 0, 1)]
+        [InlineData(0, 0, 1, 2, 1)]
+        [InlineData(0, 1, 2, 0, 1)]
+        [InlineData(0, 1, 2, 3, 1)]
+        public void OrbitalIntegralEnumerateOrbitalSymmetriesTrivialTest(int i, int j, int k, int l, int elements)
+        {
+            OrbitalIntegral orbitalIntegral = new OrbitalIntegral(new int[] { i, j, k, l }, 0.0, OrbitalIntegral.PermutationSymmetry.Trivial);
+            var orbitalIntegrals = orbitalIntegral.EnumerateOrbitalSymmetries();
+            Assert.Equal(elements, orbitalIntegrals.Length);
+        }
     }
 }

Chemistry/tests/DataModelTests/SerializationTests/BroombridgeTests.cs

@@ -8,10 +8,13 @@ using System.IO;
 using System.Linq;
 
 using Microsoft.Quantum.Chemistry.Broombridge;
+using Microsoft.Quantum.Chemistry.Fermion;
+using Microsoft.Quantum.Chemistry.OrbitalIntegrals;
 
 using Newtonsoft.Json;
 
 using Xunit;
+using YamlDotNet.Core.Tokens;
 
 namespace Microsoft.Quantum.Chemistry.Tests
 {
@@ -139,4 +142,37 @@ namespace Microsoft.Quantum.Chemistry.Tests
             Assert.Equal(original.Schema, serialized.Schema);
         }
     }
+
+
+    public class Broombridgev0_3Tests
+    {
+        public string Filename_trivial_symmetry = "Broombridge/H2O-6_trivial_v0.3.yaml";
+        public string Filename_fourfold_symmetry = "Broombridge/H2O-6_fourfold_v0.3.yaml";
+
+       
+        // Check that fully expanded trivial and fourfold symmetries lead to the same Hamiltonian. 
+        [Fact]
+        public void DeserializeVersionNumbers()
+        {
+            var broombridge_trivial = Deserializers.Deserialize<V0_3.Data>(Filename_trivial_symmetry);
+            var broombridge_fourfold = Deserializers.Deserialize<V0_3.Data>(Filename_fourfold_symmetry);
+
+            var trivial_Hamiltonian = V0_3.ToOrbitalIntegralHamiltonian(broombridge_trivial.ProblemDescriptions.Single());
+            var fourfold_Hamiltonian = V0_3.ToOrbitalIntegralHamiltonian(broombridge_fourfold.ProblemDescriptions.Single());
+
+            FermionHamiltonian x = trivial_Hamiltonian.ToFermionHamiltonian();
+            FermionHamiltonian y = fourfold_Hamiltonian.ToFermionHamiltonian();
+            foreach(var termType in y.Terms)
+            {
+                foreach (var term in termType.Value)
+                {
+                    y.Terms[termType.Key][term.Key] = -term.Value;
+                }
+            }
+
+            x.AddHamiltonian(y);
+
+            Assert.Equal(x.Norm(), 0.0);
+        }
+    }
 }