Report a bug of ITensorMPOConstruction

[mankai-chow]

I encounter the following error message when using ITensorMPOConstruction.

ERROR: LoadError: MethodError: no method matching set_scalar!(::OpIDSum{ComplexF64}, ::Int64, ::Float64)

Closest candidates are:
  set_scalar!(::OpIDSum{C}, ::Integer, ::C) where C
   @ ITensorMPOConstruction ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/OpIDSum.jl:84

Stacktrace:
 [1] macro expansion
   @ ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/OpIDSum.jl:158 [inlined]
 [2] merge_terms!(os::OpIDSum{ComplexF64})
   @ ITensorMPOConstruction ~/.julia/packages/TimerOutputs/Lw5SP/src/TimerOutput.jl:237
 [3] macro expansion
   @ ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/OpIDSum.jl:309 [inlined]
 [4] prepare_opID_sum!(os::OpIDSum{ComplexF64}, sites::Vector{Index{Int64}}, opCacheVec::Vector{Vector{OpInfo}}, basisOpCacheVec::Vector{Vector{OpInfo}})
   @ ITensorMPOConstruction ~/.julia/packages/TimerOutputs/Lw5SP/src/TimerOutput.jl:237
 [5] MPO_new(ValType::Type{Float64}, os::OpIDSum{ComplexF64}, sites::Vector{Index{Int64}}, opCacheVec::Vector{Vector{OpInfo}}; basisOpCacheVec::Vector{Vector{OpInfo}}, tol::Int64)
   @ ITensorMPOConstruction ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/MPOConstruction.jl:255
 [6] MPO_new
   @ ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/MPOConstruction.jl:245 [inlined]
 [7] MPO_new(os::OpIDSum{ComplexF64}, sites::Vector{Index{Int64}}, opCacheVec::Vector{Vector{OpInfo}}; basisOpCacheVec::Vector{Vector{OpInfo}}, tol::Int64)
   @ ITensorMPOConstruction ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/MPOConstruction.jl:264
 [8] MPO_new(os::Sum{Scaled{ComplexF64, Prod{Op}}}, sites::Vector{Index{Int64}}; basisOpCacheVec::Vector{Vector{OpInfo}}, tol::Int64)
   @ ITensorMPOConstruction ~/.julia/packages/ITensorMPOConstruction/VZH0Q/src/MPOConstruction.jl:284
 [9] top-level scope

The minimal example I have is

using ITensors
using ITensorMPOConstruction
os = OpSum()
os += "Cdag", 2, "C", 2, "Cdag", 1, "C", 1
os += "Cdag", 1, "C", 1, "Cdag", 2, "C", 2
sites = siteinds("Fermion", 2)
operatorNames = [ "I", "C", "Cdag", "N" ]
opCacheVec = [ [OpInfo(ITensors.Op(name, n), sites[n]) for name in operatorNames] for n in eachindex(sites)  ]
mpo = MPO_new(os, sites ; basisOpCacheVec = opCacheVec)

The error would not occur if either of the two terms were removed.

[corbett5]

Sorry for the delay, I was on vacation. Once #20 is merged it should be fixed.