Merge pull request #40 from amitjamadagni/expect

Function expectationvalue added.
JuliaAttic · Mar 14, 2016 · cc2c394 · cc2c394
2 parents c8fdb89 + 8dbcc76
commit cc2c394
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diff --git a/src/arrays/arraymath.jl b/src/arrays/arraymath.jl
@@ -198,8 +198,15 @@ tensor(bra::DualVector, ket::AbstractQuVector) = tensor(ket, bra)
 commute(a::AbstractQuMatrix, b::AbstractQuMatrix) = (a*b) - (b*a)
 anticommute(a::AbstractQuMatrix, b::AbstractQuMatrix) = (a*b) + (b*a)
 
+################
+#  Expectation #
+################
+expectationvalue(qarr::AbstractQuVector, op::AbstractQuMatrix) = qarr'*op*qarr
+expectationvalue(qarr::AbstractQuMatrix, op::AbstractQuMatrix) = trace(qarr*op)
+
 export normalize,
     normalize!,
     tensor,
     commute,
-    anticommute
+    anticommute,
+    expectationvalue
diff --git a/test/multest.jl b/test/multest.jl
@@ -55,3 +55,7 @@ qv1 = normalize!(QuArray(v1))
 
 # Vectorize
 @assert vec(qv) == vec(qv')
+
+# Expectation value
+@assert expectationvalue(qv1, sigmax) == qv1'*sigmax*qv1
+@assert expectationvalue(qm, lowerop(3)) == trace(qm*lowerop(3))