Add utility isfinite(::AbstractLattice) (#31)

Author: lkdvos

src/lattices/chains.jl

@@ -10,6 +10,7 @@ struct InfiniteChain <: AbstractLattice{1}
     end
 end
 Base.axes(::InfiniteChain) = ((-typemax(Int)):typemax(Int),)
+Base.isfinite(::Type{InfiniteChain}) = false
 
 """
     FiniteChain(length::Integer=1)
@@ -23,6 +24,7 @@ struct FiniteChain <: AbstractLattice{1}
     end
 end
 Base.axes(chain::FiniteChain) = (1:(chain.L),)
+Base.isfinite(::Type{FiniteChain}) = true
 
 const Chain = Union{InfiniteChain,FiniteChain}
 

src/lattices/squarelattice.jl

@@ -15,6 +15,7 @@ struct InfiniteStrip <: AbstractLattice{2}
 end
 InfiniteLadder(N::Integer) = InfiniteStrip(2, N)
 Base.axes(strip::InfiniteStrip) = (1:(strip.L), (-typemax(Int)):typemax(Int))
+Base.isfinite(::Type{InfiniteStrip}) = false
 
 """
     InfiniteCylinder(L::Int, N::Int)
@@ -33,6 +34,7 @@ struct InfiniteCylinder <: AbstractLattice{2}
 end
 
 Base.axes(::InfiniteCylinder) = ((-typemax(Int)):typemax(Int), (-typemax(Int)):typemax(Int))
+Base.isfinite(::Type{InfiniteCylinder}) = false
 
 """
     InfiniteHelix(L::Integer, N::Integer)
@@ -51,6 +53,7 @@ end
 function Base.axes(::InfiniteHelix)
     return ((-typemax(Int)):typemax(Int), (-typemax(Int)):typemax(Int))
 end
+Base.isfinite(::Type{InfiniteHelix}) = false
 
 ############################################################################################
 

src/lattices/triangularlattice.jl

@@ -17,6 +17,8 @@ struct HoneycombYC <: AbstractLattice{2}
     end
 end
 
+Base.isfinite(::Type{HoneycombYC}) = false
+
 # TODO: do proper boundscheck
 function Base.checkbounds(::Type{Bool}, lattice::HoneycombYC, inds::Vararg{Int,2})
     return true