Fix minor things (#20)

* Fix showcoeff for non-numeric coefficients

* Convenience constructor for NBodyMatrixElement from one NBodyTerm

* Allow rectangular energy expressions

* Bump version

Project.toml

@@ -1,7 +1,7 @@
 name = "EnergyExpressions"
 uuid = "f4b57a2e-27c7-11e9-0cb0-edd185b706f6"
 authors = ["Stefanos Carlström <[email protected]>"]
-version = "0.1.1"
+version = "0.1.2"
 
 [deps]
 AtomicLevels = "10933b4c-d60f-11e8-1fc6-bd9035a249a1"

src/bit_configurations.jl

@@ -536,9 +536,9 @@ function Base.Matrix(bcs::BitConfigurations, rows, op::QuantumOperator, cols; ve
            reduce(vcat, V), m, n)
 end
 
-function Base.Matrix(bcs::BitConfigurations, op::QuantumOperator; kwargs...)
-    m = length(bcs)
-    Matrix(bcs, 1:m, op, 1:m; kwargs...)
+function Base.Matrix(bcs::BitConfigurations, op::QuantumOperator; left=Colon(), right=Colon(), kwargs...)
+    ms = 1:length(bcs)
+    Matrix(bcs, ms[left], op, ms[right]; kwargs...)
 end
 
 export BitConfigurations

src/nbody_matrix_elements.jl

@@ -294,6 +294,8 @@ struct NBodyMatrixElement
     terms::Vector{NBodyTerm}
 end
 
+NBodyMatrixElement(term::NBodyTerm) = NBodyMatrixElement([term])
+
 Base.zero(::Type{NBodyMatrixElement}) =
     NBodyMatrixElement(NBodyTerm[])
 
@@ -830,7 +832,7 @@ Base.Matrix(op::QuantumOperator, cfgs::CFGs,
             overlaps::Vector{<:OrbitalOverlap}=OrbitalOverlap[]; kwargs...) where {CFGs<:AbstractVector} =
                 Matrix(cfgs, op, cfgs, overlaps; kwargs...)
 
-function transform(fun::Function, E::EnergyExpression; verbosity=0)
+function transform(fun::Function, E::EnergyExpression; verbosity=0, kwargs...)
     m,n = size(E)
 
     I = Int[]

src/show_coefficients.jl

@@ -25,3 +25,8 @@ function showcoeff(io::IO, n::Number, show_sign::Bool, show_one::Bool=false)
         write(io, "1")
     end
 end
+
+function showcoeff(io::IO, n, show_sign::Bool, _)
+    show_sign && write(io, "+ ")
+    print(io, n)
+end

test/bit_configurations.jl

@@ -602,5 +602,8 @@ end
         @test val ==  [ome(1, h, 1) + ome(2, h, 2) + ome(3, h, 3) ome(3, h, 6)*s
                        ome(6, h, 3)*s' ome(1, h, 1) + ome(5, h, 5) + ome(6, h, 6)]
         @test occursin("[ Info: Generating energy expression\n", err)
+
+        @test Matrix(bcs, h, left=1, right=2) == reshape([ome(3, h, 6)*s],1,1)
+        @test Matrix(bcs, h, left=1, right=1:2) == reshape([ome(1, h, 1) + ome(2, h, 2) + ome(3, h, 3),ome(3, h, 6)*s],1,2)
     end
 end

test/nbody_matrix_elements.jl

@@ -80,6 +80,10 @@
         n = nbt(m, s)
         @test n == nbt(m, s)
         @test n == convert(NBodyTerm, m)*convert(NBodyTerm, s)
+
+        # This is rather contrived, but just to make sure the printing
+        # does not crash if NBodyTerm::coeff is not a number.
+        @test string(NBodyTerm(Vector{EnergyExpressions.NBodyTermFactor}(),OrbitalOverlap(:a,:b))) == "⟨a|b⟩"
     end
 
     @testset "NBodyMatrixElement" begin
@@ -90,6 +94,7 @@
 
         @test o == one(z)
         @test isone(o)
+        @test o == NBodyMatrixElement(one(NBodyTerm))
 
         @test z == zero(o)
         @test iszero(z)