I’m trying to simulate a projection measurement of quantum system, here is the code involving error

‘’’

# Calculate eigenvalues and eigenvectors

eigen = eigs(X1.data)

eigenvalues = eigen.values

eigenvectors = eigen.vectors

‘’’

X1 is a four-mode operator, the error happens at the “eigenvalues=eigen.values”, and here is the error message:

ERROR: type Tuple has no field values

Stacktrace:

[1] getproperty(x::Tuple{Vector{ComplexF64}, Matrix{ComplexF64}, Int64, Int64, Int64, Vector{ComplexF64}}, f::Symbol)

I don’t understand what caused this error and how could I fix this?