Make N a named argument to spin_matrices

src/Integrators.jl

@@ -146,7 +146,7 @@ end
 
 # Returns (Λ + B⋅S) Z
 @generated function mul_spin_matrices(Λ, B::Sunny.Vec3, Z::Sunny.CVec{N}) where N
-    S = Sunny.spin_matrices(N)
+    S = spin_matrices(; N)
     out = map(1:N) do i
         out_i = map(1:N) do j
             terms = Any[:(Λ[$i,$j])]

src/Operators/Rotation.jl

@@ -61,7 +61,7 @@ end
 function unitary_for_rotation(R::Mat3; N::Int)
     !(R'*R ≈ I)   && error("Not an orthogonal matrix, R = $R.")
     !(det(R) ≈ 1) && error("Matrix includes a reflection, R = $R.")
-    S = spin_matrices(N)
+    S = spin_matrices(; N)
     n, θ = axis_angle(R)
     return exp(-im*θ*(n'*S))
 end

src/Operators/Spin.jl

@@ -1,11 +1,11 @@
 """
-    spin_matrices(N)
+    spin_matrices(; N)
 
 Constructs the three spin operators, i.e. the generators of SU(2), in the
 `N`-dimensional irrep. See also [`spin_operators`](@ref), which determines the
 appropriate value of `N` for a given site index.
 """
-function spin_matrices(N::Int)
+function spin_matrices(; N::Int)
     if N == 0
         return fill(zeros(ComplexF64,0,0), 3)
     end
@@ -23,7 +23,7 @@ end
 
 # Returns ⟨Z|Sᵅ|Z⟩
 @generated function expected_spin(Z::CVec{N}) where N
-    S = spin_matrices(N)
+    S = spin_matrices(; N)
     elems_x = SVector{N-1}(diag(S[1], 1))
     elems_z = SVector{N}(diag(S[3], 0))
     lo_ind = SVector{N-1}(1:N-1)
@@ -45,7 +45,7 @@ end
 # http://www.emis.de/journals/SIGMA/2014/084/
 ket_from_dipole(_::Vec3, ::Val{0}) :: CVec{0} = zero(CVec{0})
 function ket_from_dipole(dip::Vec3, ::Val{N}) :: CVec{N} where N
-    S = spin_matrices(N) 
+    S = spin_matrices(; N)
     λs, vs = eigen(dip' * S)
     return CVec{N}(vs[:, argmax(real.(λs))])
 end

src/Operators/Stevens.jl

@@ -77,7 +77,7 @@ function stevens_matrices(k::Int; N::Int)
     if k >= N
         return fill(zeros(ComplexF64, N, N), 2k+1)
     else
-        return stevens_abstract_polynomials(; J=spin_matrices(N), k)
+        return stevens_abstract_polynomials(; J=spin_matrices(; N), k)
     end
 end
 
@@ -202,7 +202,7 @@ in the large-``S`` classical limit is
 # Examples
 
 ```julia
-S = spin_matrices(5)
+S = spin_matrices(N=5)
 print_stevens_expansion(S[1]^4 + S[2]^4 + S[3]^4)
 # Prints: (1/20)𝒪₄₀ + (1/4)𝒪₄₄ + 102/5
 ```

src/Operators/Symbolic.jl

@@ -63,7 +63,7 @@ const 𝒮 = spin_operator_symbols
 # Construct explicit N-dimensional matrix representation of operator
 function operator_to_matrix(p::DP.AbstractPolynomialLike; N) 
     rep = p(
-        𝒮 => spin_matrices(N),
+        𝒮 => spin_matrices(; N),
         [stevens_operator_symbols[k] => stevens_matrices(k; N) for k=1:6]... 
     )
     if !(rep ≈ rep')

src/Operators/TensorOperators.jl

@@ -97,8 +97,8 @@ end
 # Returns the spin operators for two sites, with Hilbert space dimensions N₁ and
 # N₂, respectively.
 function spin_pair(N1, N2)
-    S1 = Sunny.spin_matrices(N1)
-    S2 = Sunny.spin_matrices(N2)
+    S1 = spin_matrices(N=N1)
+    S2 = spin_matrices(N=N2)
     return local_quantum_operators(S1, S2)
 end
 

src/SpinWaveTheory/SpinWaveTheory.jl

@@ -64,7 +64,7 @@ function generate_local_sun_gens(sys :: System)
     Nₘ, N = length(sys.dipoles), sys.Ns[1] # number of magnetic atoms and dimension of Hilbert 
     S = (N-1)/2
 
-    s_mat_N = spin_matrices(N)
+    s_mat_N = spin_matrices(; N)
 
     # we support the biquad interactions now in the :dipole mode
     # we choose a particular basis of the nematic operators listed in Appendix B of *Phys. Rev. B 104, 104409*
@@ -76,7 +76,7 @@ function generate_local_sun_gens(sys :: System)
     Q_mat_N[5] = √3 * s_mat_N[3] * s_mat_N[3] - 1/√3 * S * (S+1) * I
 
     if sys.mode == :SUN
-        s_mat_N = spin_matrices(N)
+        s_mat_N = spin_matrices(; N)
 
         s̃_mat = Array{ComplexF64, 4}(undef, N, N, 3, Nₘ)
         T̃_mat = Array{ComplexF64, 3}(undef, N, N, Nₘ)
@@ -98,7 +98,7 @@ function generate_local_sun_gens(sys :: System)
         end
 
     elseif sys.mode == :dipole
-        s_mat_2 = spin_matrices(2)
+        s_mat_2 = spin_matrices(N=2)
 
         s̃_mat = Array{ComplexF64, 4}(undef, 2, 2, 3, Nₘ)
 

src/System/System.jl

@@ -429,8 +429,8 @@ Each is an ``N×N`` matrix of appropriate dimension ``N``.
 
 See also [`print_stevens_expansion`](@ref).
 """
-spin_operators(sys::System{N}, i::Int) where N = spin_matrices(sys.Ns[i])
-spin_operators(sys::System{N}, site::Site) where N = spin_matrices(sys.Ns[to_atom(site)])
+spin_operators(sys::System{N}, i::Int) where N = spin_matrices(N=sys.Ns[i])
+spin_operators(sys::System{N}, site::Site) where N = spin_matrices(N=sys.Ns[to_atom(site)])
 
 """
     stevens_operators(sys, i::Int)
@@ -446,7 +446,7 @@ stevens_operators(sys::System{N}, site::Site) where N = StevensMatrices(sys.Ns[t
 
 
 function spin_operators(sys::System{N}, b::Bond) where N
-    Si = spin_matrices(sys.Ns[b.i])
-    Sj = spin_matrices(sys.Ns[b.j])
+    Si = spin_matrices(N=sys.Ns[b.i])
+    Sj = spin_matrices(N=sys.Ns[b.j])
     return local_quantum_operators(Si, Sj)
 end

test/test_operators.jl

@@ -4,7 +4,7 @@
     ### Verify 𝔰𝔲(2) irreps
     for N = 2:5
         S₀ = (N-1)/2
-        S = Sunny.spin_matrices(N)
+        S = spin_matrices(; N)
 
         for i in 1:3, j in 1:3
             # Test commutation relations
@@ -32,7 +32,7 @@
         Λ = randn(ComplexF64, N, N)
         B = randn(Sunny.Vec3)
         Z = randn(Sunny.CVec{N})
-        @test Sunny.mul_spin_matrices(Λ, B, Z) ≈ (Λ + B'*Sunny.spin_matrices(N)) * Z
+        @test Sunny.mul_spin_matrices(Λ, B, Z) ≈ (Λ + B'*spin_matrices(; N)) * Z
     end    
 end
 
@@ -94,7 +94,7 @@ end
 
     # Check transformation properties of spherical tensors
     for N in 2:7
-        S = Sunny.spin_matrices(N)
+        S = spin_matrices(; N)
         Sp = S[1] + im*S[2]
         Sm = S[1] - im*S[2]
 
@@ -103,7 +103,7 @@ end
             T = spherical_tensors(k; N)
 
             # Generators of rotations in the spin-k representation
-            K = Sunny.spin_matrices(2k+1)
+            K = spin_matrices(N=2k+1)
 
             # The selected basis is q ∈ [|k⟩, |k-1⟩, ... |-k⟩]. This function
             # converts from a q value to a 1-based index.
@@ -186,7 +186,7 @@ end
 
     # Test that spin matrices rotate as vectors
     let
-        S = Sunny.spin_matrices(N)
+        S = spin_matrices(; N)
         @test R * S ≈ rotate_operator.(S, Ref(R))
     end
 
@@ -258,7 +258,7 @@ end
     @test capt.output == "(1/20)𝒪₄₀ + (1/4)𝒪₄₄ + (3/5)X²\n"
 
     capt = IOCapture.capture() do
-        S = spin_matrices(5)
+        S = spin_matrices(N=5)
         print_stevens_expansion(S[1]^4 + S[2]^4 + S[3]^4)
     end
     @test capt.output == "(1/20)𝒪₄₀ + (1/4)𝒪₄₄ + 102/5\n"

test/test_structure_factors.jl

@@ -26,7 +26,7 @@
     # Test sum rule with custom observables 
     sys = simple_model_sf(; mode=:SUN)
     thermalize_simple_model!(sys; kT=0.1)
-    S = Sunny.spin_matrices(2)
+    S = spin_matrices(N=2)
     observables = cat(S...; dims=3)
     sf = DynamicStructureFactor(sys; nω=100, ωmax=10.0, Δt=0.1, apply_g=false, observables)
     qgrid = all_exact_wave_vectors(sf)