Small fixes and improvements

src/operators/spinoperators.jl

@@ -19,7 +19,7 @@ function spinmatrices(s::Union{Rational{Int},Int}, elt=ComplexF64)
     N = Int(2 * s)
 
     Sx = zeros(elt, N + 1, N + 1)
-    Sy = zeros(elt, N + 1, N + 1)
+    Sy = zeros(complex(elt), N + 1, N + 1)
     Sz = zeros(elt, N + 1, N + 1)
 
     for row in 1:(N + 1)
@@ -417,13 +417,13 @@ S_exchange(elt::Type{<:Number}; kwargs...) = S_exchange(elt, Trivial; kwargs...)
 function S_exchange(symmetry::Type{<:Sector}; kwargs...)
     return S_exchange(ComplexF64, symmetry; kwargs...)
 end
-
-function S_exchange(elt::Type{<:Number}, ::Type{Trivial}; spin=1 // 2)
-    return S_xx(elt, Trivial; spin=spin) +
-           S_yy(elt, Trivial; spin=spin) +
-           S_zz(elt, Trivial; spin=spin)
+function S_exchange(elt::Type{<:Number}, symmetry::Type{<:Sector}; spin=1 // 2)
+    elt_complex = complex(elt)
+    SS = (S_plusmin(elt_complex, symmetry; spin=spin) +
+          S_minplus(elt_complex, symmetry; spin=spin)) / 2 +
+         S_zz(elt_complex, symmetry; spin=spin)
+    return elt <: Real ? real(SS) : SS
 end
-
 function S_exchange(elt::Type{<:Number}, ::Type{SU2Irrep}; spin=1 // 2)
     pspace = SU2Space(spin => 1)
     aspace = SU2Space(1 => 1)
@@ -435,11 +435,6 @@ function S_exchange(elt::Type{<:Number}, ::Type{SU2Irrep}; spin=1 // 2)
     return SS
 end
 
-function S_exchange(elt::Type{<:Number}, symmetry::Type{<:Sector}; spin=1 // 2)
-    return (S_plusmin(elt, symmetry; spin=spin) + S_minplus(elt, symmetry; spin=spin)) / 2 +
-           S_zz(elt, symmetry; spin=spin)
-end
-
 const SS = S_exchange
 
 """Pauli exchange operator."""

test/hubbardoperators.jl

@@ -41,7 +41,7 @@ implemented_symmetries = [(Trivial, Trivial), (U1Irrep, U1Irrep), (U1Irrep, SU2I
     end
 end
 
-function hamiltonian(particle_symmetry, spin_symmetry; t, U, mu, L)
+function hubbard_hamiltonian(particle_symmetry, spin_symmetry; t, U, mu, L)
     hopping = t * (e_plusmin(particle_symmetry, spin_symmetry) +
                    e_minplus(particle_symmetry, spin_symmetry))
     interaction = U * e_number_updown(particle_symmetry, spin_symmetry)
@@ -65,7 +65,7 @@ end
     U = randn()
     mu = randn()
 
-    H_triv = hamiltonian(Trivial, Trivial; t, U, mu, L)
+    H_triv = hubbard_hamiltonian(Trivial, Trivial; t, U, mu, L)
     vals_triv = mapreduce(vcat, eigvals(H_triv)) do (c, v)
         return repeat(real.(v), dim(c))
     end
@@ -75,7 +75,7 @@ end
         if (particle_symmetry, spin_symmetry) == (Trivial, Trivial)
             continue
         end
-        H_symm = hamiltonian(particle_symmetry, spin_symmetry; t, U, mu, L)
+        H_symm = hubbard_hamiltonian(particle_symmetry, spin_symmetry; t, U, mu, L)
         vals_symm = mapreduce(vcat, eigvals(H_symm)) do (c, v)
             return repeat(real.(v), dim(c))
         end

test/spinoperators.jl

@@ -133,6 +133,15 @@ end
           S_xx(U1Irrep; spin=spin) + S_yy(U1Irrep; spin=spin) + S_zz(U1Irrep; spin=spin) rtol = 1e-3
 end
 
+@testset "Real eltype" begin
+    for operator in (S_x, S_z, S_xx, S_zz, S_plusmin, S_minplus, S_exchange),
+        symmetry in (Trivial, Z2Irrep, U1Irrep)
+
+        @test real(operator(ComplexF64, symmetry)) ≈ operator(Float64, symmetry)
+    end
+    @test real(S_exchange(ComplexF64, SU2Irrep)) ≈ S_exchange(Float64, SU2Irrep)
+end
+
 # potts_ZZ test?
 @testset "non-symmetric Q-state potts operators" for Q in 3:5
     # inferrability

test/tjoperators.jl

@@ -74,7 +74,7 @@ implemented_symmetries = [(Trivial, Trivial),
     end
 end
 
-function hamiltonian(particle_symmetry, spin_symmetry; t, J, mu, L, slave_fermion)
+function tjhamiltonian(particle_symmetry, spin_symmetry; t, J, mu, L, slave_fermion)
     num = tJ.e_number(particle_symmetry, spin_symmetry; slave_fermion)
     hop_heis = (-t) * (tJ.e_plusmin(particle_symmetry, spin_symmetry; slave_fermion) +
                        tJ.e_minplus(particle_symmetry, spin_symmetry; slave_fermion)) +
@@ -98,7 +98,7 @@ end
     mu = randn()
 
     for slave_fermion in (false, true)
-        H_triv = hamiltonian(Trivial, Trivial; t, J, mu, L, slave_fermion)
+        H_triv = tjhamiltonian(Trivial, Trivial; t, J, mu, L, slave_fermion)
         vals_triv = mapreduce(vcat, eigvals(H_triv)) do (c, v)
             return repeat(real.(v), dim(c))
         end
@@ -108,8 +108,8 @@ end
             if (particle_symmetry, spin_symmetry) == (Trivial, Trivial)
                 continue
             end
-            H_symm = hamiltonian(particle_symmetry, spin_symmetry; t, J, mu, L,
-                                 slave_fermion)
+            H_symm = tjhamiltonian(particle_symmetry, spin_symmetry; t, J, mu, L,
+                                   slave_fermion)
             vals_symm = mapreduce(vcat, eigvals(H_symm)) do (c, v)
                 return repeat(real.(v), dim(c))
             end