Readme update for v0.3.3

README.md

@@ -23,28 +23,28 @@ julia> basis = symmetrized_basis(zbasis(9, 4), Flip(9), 0, Shift(9), 0);
 julia> state = normalize!(ones(2^9)); # initial state - all up in x direction
 
 julia> @btime symm_state = symmetrize_state(state, basis)
- 765.253 μs (7781 allocations: 727.29 KiB)
-14-element Vector{ComplexF64}:
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
- 0.18750000000000006 + 0.0im
+637.317 μs (4245 allocations: 646.05 KiB)
+14-element Vector{Float64}:
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
+ 0.18749999999999994
 
 julia> operator = kron([1 0; 0 -1], kron([1 0; 0 -1], I(2^7))); # operator Z ⊗ Z ⊗ 𝟙 ⊗ .. ⊗ 𝟙
 
 julia> @btime symm_op = symmetrize_operator(operator, basis)
- 41.828 ms (922891 allocations: 29.66 MiB)
-14×14 Matrix{ComplexF64}:
+ 1.096 ms (4248 allocations: 703.76 KiB)
+14×14 Matrix{Float64}:
 [...]
 ```
 
@@ -62,6 +62,8 @@ The symmetry operations supported are:
 
 where `N` denotes the number of spins in the system and their positions should be given as a Julian index, i.e. in the range `1:N`.
 
+To get the tranformation matrix to the symmetrized subspace just use `transformationmatrix(symmetrized_basis)`.
+
 **Note:** The projection on a specific magnetization block is applied first. Thus if you have spin flip symmetry and restrict to a magnetization block, your symmetrized basis states look like "|↑..↑⟩ ± |↓..↑⟩". So in this case you effectively specified S_z^2 and parity.
 
 ## User-defined symmetries

src/SpinSymmetry.jl

@@ -1,10 +1,10 @@
 module SpinSymmetry
 
-import SparseArrays
+using SparseArrays: sparse
 
 export Flip, Shift, Swap, SpatialReflection, GenericSymmetry
 export zbasis, FullZBasis, ZBlockBasis, basissize
-export SymmetrizedBasis, symmetrized_basis, symmetrize_state, symmetrize_operator
+export SymmetrizedBasis, symmetrized_basis, symmetrize_state, symmetrize_operator, transformationmatrix
 
 include("abstract.jl")
 include("basis.jl")

src/basis.jl

@@ -162,7 +162,7 @@ function symmetrize_state(state, basis::SymmetrizedBasis)
         throw(ArgumentError("""State has wrong size.
             Expected $(2^basis.basis.N), got: $(length(state))"""))
     end
-    return _transformationmatrix(basis) * state
+    return transformationmatrix(basis) * state
     # inds = _indices(basis.basis)
     # factors = _phase_factors(inds, basis.symmetries, basis.sectors)
     # use_real = all(d -> all(denominator.(values(d)) .<= 2), factors)
@@ -200,7 +200,7 @@ function symmetrize_operator(operator, basis::SymmetrizedBasis)
             Expected $(2^basis.basis.N)x$(2^basis.basis.N), got: $(size(operator))"""))
     end
 
-    trafo = _transformationmatrix(basis)
+    trafo = transformationmatrix(basis)
 
     return trafo * operator * trafo'
 
@@ -303,8 +303,7 @@ function _phase_factors(inds, symms, sectors)
     output
 end
 
-SparseArrays.sparse(symmbasis::SymmetrizedBasis) = _transformationmatrix(symmbasis)
-function _transformationmatrix(symmbasis)
+function transformationmatrix(symmbasis)
 	inds = SpinSymmetry._indices(symmbasis.basis)
 	phases = SpinSymmetry._phase_factors(inds, symmbasis.symmetries, symmbasis.sectors)
 
@@ -326,5 +325,5 @@ function _transformationmatrix(symmbasis)
 			index += 1
 		end
 	end
-	SparseArrays.sparse(I,J,V,length(phases), 2^(symmbasis.basis.N))
+	sparse(I,J,V,length(phases), 2^(symmbasis.basis.N))
 end