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Migrate from cadCAD

radCAD already uses the cadCAD generalised dynamical-systems model structure, so your existing state update blocks, policies, and state update functions work as-is. You have two migration paths: rewrite the configuration using radCAD's API, or keep your cadCAD configuration and use compatibility mode.

Option 1: Rewrite using the radCAD API

radCAD replaces cadCAD's multi-step configuration (config_sim, append_configs, ExecutionContext, Executor, the global configs list) with three classes.

from cadCAD.configuration.utils import config_sim
from cadCAD.configuration import Experiment
from cadCAD.engine import ExecutionMode, ExecutionContext, Executor
from cadCAD import configs

del configs[:]  # clear any prior configs

sim_config = config_sim({
    "N": 1,            # Monte Carlo runs
    "T": range(100),   # timesteps
    "M": system_params,
})

experiment.append_configs(
    initial_state=initial_state,
    partial_state_update_blocks=partial_state_update_blocks,
    sim_configs=sim_config,
)

exec_context = ExecutionContext()
simulation = Executor(exec_context=exec_context, configs=configs)
result, _tensor_field, _sessions = simulation.execute()

df = pd.DataFrame(result)

from radcad import Model, Simulation, Experiment

model = Model(
    initial_state=initial_state,
    state_update_blocks=state_update_blocks,
    params=params,
)
simulation = Simulation(
    model=model,
    timesteps=100,   # Number of timesteps
    runs=1,          # Number of Monte Carlo runs
)

result = simulation.run()
df = pd.DataFrame(result)

Note the rename: cadCAD's partial_state_update_blocks is state_update_blocks in radCAD.

Option 2: Compatibility mode

Compatibility mode translates the cadCAD configuration and execution process into radCAD, so you can run an existing cadCAD model with minimal changes. It does not handle every cadCAD option, but works for most models.

1. Install the compat extra:

pip install -e ".[compat]"

poetry install -E compat

uv sync --extra compat

2. Repoint your cadCAD imports from cadCAD.* to radcad.compat.cadCAD.*:

from radcad.compat.cadCAD.configuration import Experiment
from radcad.compat.cadCAD.engine import Executor, ExecutionMode, ExecutionContext
from radcad.compat.cadCAD.configuration.utils import config_sim
from radcad.compat.cadCAD import configs

Your existing cadCAD model now runs on radCAD.

See also