Fix LocalOperator constructor for indices of type Tuple{Int,Int} (#176)

* Remove unnecessary type restriction on _safe_pow

* Fix optimizer verbosity in `fixedpoint` algorithm selector

* Fix tuple indices in LocalOperator constructor

Author: pbrehmer

src/algorithms/select_algorithm.jl

@@ -43,7 +43,7 @@ function select_algorithm(
 
     # adjust optimizer tol and verbosity
     if optimizer_alg isa NamedTuple
-        defaults = (; tol, verbosity=verbosity ≤ 1 ? -1 : 3)
+        defaults = (; tol, verbosity=verbosity < 1 ? -1 : 3)
         optimizer_alg = merge(defaults, optimizer_alg)
     end
 

src/operators/localoperator.jl

@@ -14,7 +14,7 @@ and the terms are stored as a tuple of pairs of indices and operators.
 # Constructors
 
     LocalOperator(lattice::Matrix{S}, terms::Pair...)
-    LocalOperator{T,S}(lattice::Matrix{S}, terms::T) where {T,S} # expert mode
+    LocalOperator{T,S}(lattice::Matrix{S}, terms::T) where {T,S}
 
 # Examples
 
@@ -31,6 +31,7 @@ struct LocalOperator{T<:Tuple,S}
         # Check if the indices of the operator are valid with themselves and the lattice
         for (inds, operator) in terms
             @assert operator isa AbstractTensorMap
+            @assert eltype(inds) <: CartesianIndex
             @assert numout(operator) == numin(operator) == length(inds)
             @assert spacetype(operator) == S
 
@@ -52,7 +53,12 @@ function LocalOperator(
     relevant_terms = []
     for inds in unique(allinds)
         operator = sum(alloperators[findall(==(inds), allinds)])
-        norm(operator) > atol && push!(relevant_terms, inds => operator)
+        cinds = if !(eltype(inds) <: CartesianIndex) # force indices to be CartesianIndices
+            map(CartesianIndex, inds)
+        else
+            inds
+        end
+        norm(operator) > atol && push!(relevant_terms, cinds => operator)
     end
 
     terms_tuple = Tuple(relevant_terms)