Krylov dimension vs. number of Trotter steps

[neumannrf]

URL to the relevant course

https://quantum.cloud.ibm.com/learning/en/courses/quantum-diagonalization-algorithms/krylov#41-step-1-map-problem-to-quantum-circuits-and-operators

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• new content request
• typo
• code bug
• out-of-date content
• broken link
• other

Describe the fix or the content request.

The text says

Let us specify the maximum Krylov dimension we wish to use, though we will check for convergence at smaller dimensions. We also specify the number of Trotter steps to use in the time evolution. In this case, we set the Krylov dimension to be equal to the number of Trotter steps plus one. This is consistent with generating an additional Krylov vector with each application of U, plus the initial vector.

but then we define

krylov_dim = 5
num_trotter_steps = 6

which is inconsistent with the text.

My suggested fix would be to swap the numbers.

krylov_dim = 6
num_trotter_steps = 5

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I will write (or already have written) a draft of the proposed content