Error: Index::write: Index is default initialized

closed

Hi,

I am not able to save a state using the WriteToFile function.
The code returns the following error:
Index::write: Index is default initialized

It's not clear to me why it's happening.
I have a bosonic system of size N with a certain cut-off to the Fock space.
The state is the following:
$$|\psi\rangle = |0 0 ...\rangle \otimes |\psi0\rangle \otimes |00..0\rangle$$
where @@|\psi
0\rangle@@ is a certain state. Since I am able to compute local quantites and perform a TEBD real time evolution I don't see any issue with the state itself (e.g. mismatch with indices).
Could you help me?