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Help us to help you! Below are some guidelines for writing a question that will help us to help you more quickly, and reduce the amount of extra work you might need to do:

• If you are using the new Julia version of ITensor or C++ version 2, please mention this: otherwise we will assume you are using C++ version 3 of ITensor.
• If you are unsure what a line of code does, or whether a tensor has a certain property, try printing it out! Almost everything in ITensor is printable, using either the function println or the Print or PrintData functions (or the @show macro in Julia). The printouts can show you what indices an ITensor has, and you can also print the norm of an ITensor, etc.
• If you are reporting a bug or something is not working as expected, please provide some minimal code to reproduce your issue. Please refrain from posting very long, complicated codes with many functions etc.
• For physics-related questions involves a Hamiltonian, please state clearly and precisely what this Hamiltonian is, either by writing it out in Latex notation, or by providing a link to a paper (with the equation number)
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• If your question is about convergence of DMRG, please note that it is controlled mainly by two things: the choice of initial state and the accuracy/sweep parameters. Choosing a good initial state is an art, and very system dependent but nonetheless important. Also, turning on the "noise term" to a small value can often help convergence. For more about noise see this page: http://itensor.org/docs.cgi?vers=cppv3&page=tutorials/dmrg_params