Error codes¶

Every problem is reported as an issue with a code, a location in the config, a reason and a suggested fix, and several issues are reported together when possible:

[E_TARGET_REGULATED] interventions[0]: 'TIC-101.cv' is the regulated variable of loop TIC-101; nobody can set it directly. Fix: Change its reference instead: target 'TIC-101.sp'.

In Python, catch homeostat.HomeostatError (or ScenarioError, CompileError, SimulationError); its issues list holds the issues and to_dicts() gives them as dictionaries.

Code	Stage	Meaning
`E_YAML`	loading	The file is not valid YAML.
`E_FILE`	loading	The scenario file does not exist.
`E_SCHEMA`	validation	A key is unknown, missing or has the wrong type or value.
`E_BAD_DISTRIBUTION`	drawing	A distribution is malformed (for example a non-positive standard deviation).
`E_BAD_GENERATOR`	drawing	A plan or fault generator cannot make a plan (a missing key, a non-positive campaign or rate, invalid weights).
`E_DRAW_REJECTED`	drawing	Every draw of a plant failed validation; narrow the distributions.
`E_UNKNOWN_LIBRARY`	building	No domain library with that name is installed.
`E_LIBRARY_VERSION`	building	The pinned library version is not the installed one, or is not an integer.
`E_UNKNOWN_TEMPLATE`	building	The library has no template with that name.
`E_UNKNOWN_PARAM`	building	A template has no parameter with that name.
`E_BAD_PARAM`	building	A parameter value is invalid: the wrong type, outside its range, or not finite.
`E_UNKNOWN_OP`	building	There is no core operator with that name.
`E_UNKNOWN_PORT`	building	An operator has no input port with that name.
`E_DUPLICATE_OPERATOR`	building	Two operators have the same name.
`E_DUPLICATE_WRITER`	building	Two operators write the same signal; every signal has exactly one writer.
`E_UNKNOWN_FAULT`	building	The library has no fault with that name.
`E_FAULT_NOT_APPLICABLE`	building	The fault does not apply to the unit's template.
`E_UNKNOWN_DEGRADATION`	building	The library has no degradation with that name.
`E_DEGRADATION_NOT_APPLICABLE`	building	The degradation does not apply to the unit's template.
`E_UNKNOWN_TASK`	building	The library has no maintenance task with that name.
`E_TASK_NOT_APPLICABLE`	building	The task does not apply to the unit, for example cleaning a unit without fouling.
`E_UNKNOWN_REGIME`	building	A plan names a regime that is not defined under `regimes`.
`E_FAMILY`	building	A family setting is invalid, or plants in one batch disagree (for example on their starting regimes).
`E_BAD_STEP`	compiling	The base step `dt` is not positive.
`E_UNKNOWN_SIGNAL`	compiling	An input names a signal that nothing writes.
`E_MISSING_INPUT`	compiling	A required input of an operator is not connected.
`E_ALGEBRAIC_LOOP`	compiling	A cycle of signals has no operator without direct feedthrough; the error lists the cycle.
`E_BAD_FEEDBACK_INPUT`	compiling	A feedback operator reads a true value or an intermediate observation stage instead of a final measured signal.
`E_BAD_PERIOD`	compiling	An update period or phase is not a whole number of steps, not finite, or a phase is not smaller than its period.
`E_BAD_LANES`	compiling	Per-lane values have the wrong count, are out of range, or target a parameter that must be equal on every lane.
`E_BAD_MODULATION`	compiling	A parameter modulation is neither `scale` nor `shift`.
`E_NAME_COLLISION`	compiling	A name is both an operator and a parameter path.
`E_PARAM_NOT_PROMOTABLE`	compiling	A structural parameter (a buffer size, a dead time, a list) cannot change during a run.
`E_UNSTABLE_SOURCE`	compiling	AR coefficients do not give a stationary process.
`E_UNKNOWN_TARGET`	events	An event targets a signal or parameter that does not exist; the fix suggests the closest name.
`E_TARGET_REGULATED`	events	An event targets a loop's regulated variable; change its setpoint instead.
`E_TARGET_CONTROLLER_OUTPUT`	events	An event targets a controller output or the valve it drives; use manual mode and `man_out` instead.
`E_TARGET_NOT_SCHEDULABLE`	events	An event targets a signal written by a dynamic operator; target one of its parameters instead.
`E_TARGET_NOT_PROMOTED`	events	An event targets a parameter that was not promoted when the graph was compiled.
`E_BAD_EVENT`	events	An event is invalid: a bad action or profile, a mode that is not a step, a value outside the parameter's range, or no value to shift or scale yet.
`E_BAD_INIT`	running	`init` is not `steady`, `none` or `{burn_in: ...}`.
`E_INIT_NO_STEADY_STATE`	running	The plant did not settle before the step limit; the error names the states still moving.
`E_ALREADY_STARTED`	running	The engine was initialized or run already.
`E_BAD_RUN`	running	`run(until)` is not finite, not on the step grid, or before the current time.
`E_BAD_RECORDING`	running	The recording interval is not a positive whole number of steps.
`E_DELAY_EXCEEDED`	running	A variable transport delay needed longer than its `max_delay`; raise `max_delay` (or the template's maximum transit time).
`E_LABELER`	labelling	A labeler cannot label this scenario, for example visibility on a multi-lane scenario.