diff --git a/docs/user/overview.md b/docs/user/overview.md
index a7c0655d..56fdf136 100644
--- a/docs/user/overview.md
+++ b/docs/user/overview.md
@@ -27,6 +27,6 @@ Learn more in [Understanding Reporting](../tutorials/reporting_tutorial.ipynb)
 
 ## High-level vs Low-Level
 
-Under the hood, TorchSim takes a modular functional approach to atomistic simulation. Each integrator or optimizer function, such as `nvt_langevin,` takes in a model and parameters and returns `init` and `update` functions that act on a unique `State.` The state inherits from `SimState` and tracks the fixed and fluctuating parameters of the simulation, such as the `momenta` for NVT or the timestep for FIRE. The runner functions take this basic structure and wrap it in a convenient interface with autobatching and reporting.
+Under the hood, TorchSim takes a modular functional approach to atomistic simulation. Each integrator or optimizer has associated `init` and `update` functions that initialize and update a unique `State.` The state inherits from `SimState` and tracks the fixed and fluctuating parameters of the simulation, such as the `momenta` for NVT or the timestep for FIRE. The runner functions take this basic structure and wrap it in a convenient interface with autobatching and reporting.
 
 Learn more in [Fundamentals of TorchSim](../tutorials/low_level_tutorial.ipynb) and [Implementing New Methods](../tutorials/hybrid_swap_tutorial.ipynb)
diff --git a/examples/tutorials/low_level_tutorial.py b/examples/tutorials/low_level_tutorial.py
index 7677e468..eb8d63ed 100644
--- a/examples/tutorials/low_level_tutorial.py
+++ b/examples/tutorials/low_level_tutorial.py
@@ -117,10 +117,10 @@
 """
 ## Optimizers and Integrators
 
-All optimizers and integrators share a similar interface. They accept a model and
-return two functions: `init_fn` and step_fn`. The `init_fn` function returns the
-initialized optimizer-specific state, while the step_fn` function updates the
-simulation state.
+All optimizers and integrators have an associated `init_fn` and a `step_fn`.
+The `init_fn` function returns the initialized optimizer-specific state,
+while the `step_fn` function updates the simulation state. The formal pairings
+are stored in the `ts.INTEGRATOR_REGISTRY` and `ts.OPTIM_REGISTRY` dictionaries.
 
 ### Unit Cell Fire
 
@@ -128,6 +128,10 @@
 """
 
 # %%
+state = ts.fire_init(state=state, model=model, cell_filter=ts.CellFilter.unit)
+
+# add a little noise so we have something to relax
+state.positions = state.positions + torch.randn_like(state.positions) * 0.05
 
 
 # %% [markdown]
@@ -139,10 +143,6 @@
 """
 
 # %%
-state = ts.fire_init(state=state, model=model, cell_filter=ts.CellFilter.unit)
-
-# add a little noise so we have something to relax
-state.positions = state.positions + torch.randn_like(state.positions) * 0.05
 
 for step in range(20):
     state = ts.fire_step(state=state, model=model)
@@ -151,10 +151,9 @@
 
 # %% [markdown]
 """
-You can set the optimizer-specific arguments in the `optimize` function
-optimizer=ts.Optimizer.fire, cell_filter=ts.CellFilter.unit. Fixed
-parameters can usually be passed to the `init_fn` and parameters that vary over
-the course of the simulation can be passed to the step_fn`.
+Fixed parameters can usually be passed to the `init_fn` and parameters that vary over
+the course of the simulation can be passed to the `step_fn`. In the `optimize`
+function, you set these with the `init_kwargs` and `optimizer_kwargs` arguments.
 """
 
 # %%
diff --git a/torch_sim/__init__.py b/torch_sim/__init__.py
index a5a8af76..3bc1bc92 100644
--- a/torch_sim/__init__.py
+++ b/torch_sim/__init__.py
@@ -66,6 +66,7 @@
 from torch_sim.quantities import (
     calc_kinetic_energy,
     calc_kT,
+    calc_temperature,
     get_pressure,
     system_wise_max_force,
 )
diff --git a/torch_sim/quantities.py b/torch_sim/quantities.py
index 8ffc61ed..35f7d6f0 100644
--- a/torch_sim/quantities.py
+++ b/torch_sim/quantities.py
@@ -88,7 +88,7 @@ def calc_temperature(
         units (object): Units to return the temperature in
 
     Returns:
-        torch.Tensor: Temperature value in specified units
+        torch.Tensor: Temperature value in specified units (default, K)
     """
     kT = calc_kT(
         masses=masses,
diff --git a/torch_sim/runners.py b/torch_sim/runners.py
index 6e956750..4ac6f3be 100644
--- a/torch_sim/runners.py
+++ b/torch_sim/runners.py
@@ -5,6 +5,7 @@
 converting between different atomistic representations and handling simulation state.
 """
 
+import copy
 import warnings
 from collections.abc import Callable
 from dataclasses import dataclass
@@ -29,7 +30,6 @@
 def _configure_reporter(
     trajectory_reporter: TrajectoryReporter | dict,
     *,
-    state_kwargs: dict | None = None,
     properties: list[str] | None = None,
     prop_frequency: int = 10,
     state_frequency: int = 100,
@@ -53,12 +53,12 @@ def _configure_reporter(
     }
 
     # ordering is important to ensure we can override defaults
+    trajectory_reporter = copy.deepcopy(trajectory_reporter)
     return TrajectoryReporter(
         prop_calculators=trajectory_reporter.pop(
             "prop_calculators", {prop_frequency: prop_calculators}
         ),
         state_frequency=trajectory_reporter.pop("state_frequency", state_frequency),
-        state_kwargs=state_kwargs or {},
         **trajectory_reporter,
     )
 
@@ -561,13 +561,15 @@ def static(
         properties.append("forces")
     if model.compute_stress:
         properties.append("stress")
-    trajectory_reporter = _configure_reporter(
-        trajectory_reporter or dict(filenames=None),
-        state_kwargs={
+    if isinstance(trajectory_reporter, dict):
+        trajectory_reporter = copy.deepcopy(trajectory_reporter)
+        trajectory_reporter["state_kwargs"] = {
             "variable_atomic_numbers": True,
             "variable_masses": True,
             "save_forces": model.compute_forces,
-        },
+        }
+    trajectory_reporter = _configure_reporter(
+        trajectory_reporter or dict(filenames=None),
         properties=properties,
     )
 
diff --git a/torch_sim/trajectory.py b/torch_sim/trajectory.py
index c9167d0f..3220b24b 100644
--- a/torch_sim/trajectory.py
+++ b/torch_sim/trajectory.py
@@ -76,7 +76,6 @@ class TrajectoryReporter:
         trajectories (list): TorchSimTrajectory instances
         filenames (list): Trajectory file paths
         array_registry (dict): Map of array names to (shape, dtype) tuples
-        shape_warned (bool): Whether a shape warning has been issued
 
     Examples:
         >>> reporter = TrajectoryReporter(
@@ -96,7 +95,6 @@ class TrajectoryReporter:
     prop_calculators: dict[int, dict[str, Callable]]
     state_kwargs: dict[str, Any]
     metadata: dict[str, str] | None
-    shape_warned: bool
     trajectories: list["TorchSimTrajectory"]
     filenames: list[str | pathlib.Path] | None
 
@@ -140,7 +138,6 @@ def __init__(
 
         self.prop_calculators = prop_calculators or {}
         self.state_kwargs = state_kwargs or {}
-        self.shape_warned = False
         self.metadata = metadata
 
         self.trajectories = []
@@ -258,9 +255,6 @@ def report(
         all_props: list[dict[str, torch.Tensor]] = []
         # Process each system separately
         for idx, substate in enumerate(split_states):
-            # Slice the state once to get only the data for this system
-            self.shape_warned = True
-
             # Write state to trajectory if it's time
             if (
                 self.state_frequency