fix: Write correct values at step 0

[gmertes]

Description

When writing the initial state the multistep input, a 2D array containing t0 and t-6, is written to step 0. Only the 1D array of t0 should be written to step 0.

Thanks for @frazane for finding the bug and proposing the solution.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

[HCookie]

Why not use the reduce method?

anemoi-inference/src/anemoi/inference/output.py

Lines 91 to 109 in c645fb2

	@classmethod
	def reduce(cls, state: State) -> State:
	"""Create a new state which is a projection of the original state on the last step in the multi-steps dimension.
	Parameters
	----------
	state : State
	The original state.
	Returns
	-------
	State
	The reduced state.
	"""
	reduced_state = state.copy()
	reduced_state["fields"] = {}
	for field, values in state["fields"].items():
	reduced_state["fields"][field] = values[-1, :]
	return reduced_state

[gmertes]

I forgor 💀

Using reduce now.