Steady-State Simulation

Steady-state simulation solves the graph once and returns a single value for every output port. Use it to answer questions like “at this supply voltage and load current, what does the system do?”

Basic run

from hardwave.simulation import SimulationEngine, SimulationConfig
from hardwave.solvers import SimulationDomain

engine = SimulationEngine(graph)

result = engine.run(
    inputs={
        "ldo": {"load_current": 0.05},   # 50 mA load
    },
    config=SimulationConfig(domain=SimulationDomain.STEADY_STATE),
)

print(result.get_output("ldo",  "v_out"))        # 5.0
print(result.get_output("ldo",  "power_loss"))   # 0.35 W
print(result.get_output("load", "current"))      # 0.05

SimulationDomain.STEADY_STATE is the default domain. You can omit config for simple runs:

result = engine.run(inputs={"ctrl": {"temperature": 28.0}})

Parameter sweeps

Run the engine repeatedly with different external inputs to sweep parameters:

print(f"{'Temp':>6}  {'Openness':>10}  {'Vent Angle':>12}")
print("-" * 34)
for T in [18.0, 22.0, 25.0, 27.5, 30.0, 35.0, 40.0]:
    r = engine.run(inputs={"ctrl": {"temperature": T}, "servo": {"load_torque": 0.0}})
    openness = r.get_output("ctrl",       "vent_state")
    angle    = r.get_output("pos_sensor", "vent_angle_deg")
    print(f"{T:>5.1f}°C  {openness:>10.0%}  {angle:>11.1f}°")

Reading results

# Single scalar output
value = result.get_output("instance_id", "port_name")

# JSON-serializable dict
snapshot = result.to_dict()

# Diagnostics and warnings
for diag in result.diagnostics():
    print(diag)

warnings = result.get_warnings()
faults = result.get_faults()

To attach this snapshot to a cloud-saved graph for the dashboard RESULTS tab, see Saving Graphs.

Fault-aware components

DCMotor and LiPoCell emit runtime diagnostics when limits are exceeded. Check health and fault_code output ports, or filter result.get_faults().

from hardwave.simulation import SimulationConfig, FaultMode

# Default: continue with degraded outputs after a fault
result = engine.run(inputs={...})

# Stop simulation on first FAULT (raises SimulationError)
result = engine.run(
    inputs={...},
    config=SimulationConfig(fault_mode=FaultMode.STOP),
)

How execution works

engine.run() calls graph.topological_order() to get a safe evaluation sequence, then for each component:

Collects input values from upstream outputs, the inputs dict, or port defaults
Calls the component solver and runs post_solve_diagnostics()
Applies fault output degradation if the component is faulted
Stores outputs for downstream components

ODE components in steady-state use their algebraic solve() fallback (not the frozen ODE integrator state). The result object wraps this output dict so you can query by (instance_id, port_name).

Next steps

Component Faults

Runtime warnings, faults, and health output ports

Transient Simulation

Step through time and collect time-series data

Solvers

Formula, ODE, lookup table, and ML solvers

Getting Started

Guides

Simulation

Reference

Steady-State Simulation

Basic run

Parameter sweeps

Reading results

Fault-aware components

How execution works

Next steps

Component Faults

Transient Simulation

Solvers

​Basic run

​Parameter sweeps

​Reading results

​Fault-aware components

​How execution works

​Next steps

Component Faults

Transient Simulation

Solvers

Basic run

Parameter sweeps

Reading results

Fault-aware components

How execution works

Next steps