General Multirate EMT Tasks

AIMORA's general task platform provides exact deterministic logical-time execution for protection, carrier, converter-control, mechanical, source, thermal, interface, and user-defined task families. It schedules task-owned equations inside fixed-step instantaneous EMT; it does not supply or qualify those equations.

Public declaration and private execution

AIMORAProject.ControlTaskDeclaration is the callback-free project owner. Each declaration carries a stable identity, one family, exact rational epoch/period/phase/computational delay in SI seconds, integer priority, declared read and write resources, explicit predecessors, and power-history/topology/interface/output invalidations. The versioned aimora-control-schedule format round-trips these declarations exactly and refuses unknown major versions.

The public Engine maps a declaration to EMTTaskSpec, validates a complete horizon with emt_task_plan, and exposes typed family, effect, logical-time, occurrence, checkpoint, result, and failure contracts. The separately distributed licensed numerical backend privately owns due-set selection, queues, callbacks, transaction integration, and state restoration. Public project inspection and package loading never require or reveal the private dispatcher.

using AIMORA
using AIMORA.EMTTaskPlatform

specification = EMTTaskSpec(
    "sampled_source",
    SourceEMTTask,
    emt_logical_time(0),
    emt_logical_time(25 // 1_000_000),
    emt_logical_time(5 // 1_000_000),
    emt_logical_time(2 // 1_000_000);
    priority = 0,
    read_resources = ["measured_voltage"],
    write_resources = ["source_command"],
)

plan = emt_task_plan(
    [specification];
    start = emt_logical_time(0),
    stop = emt_logical_time(1 // 1_000),
)

Floating calendar inputs are deliberately refused. Rational values are normalized into one exact quantum, and every activation/release boundary becomes a checked integer tick. The admitted domain is 1 ns through 1,000 s per period, phase in [0, period), delay from zero through 100 periods, at most 1,024 tasks, 4,096 explicit dependency edges, one million activations per task, one billion horizon ticks, and 1,000 pending delayed values per task.

Ordering, delay, and hold

At every exact instant, AIMORA applies localized physical events first and then due tasks. Task order is a stable topological order; simultaneously ready tasks break ties by (priority, family, name, registration index). Two same-instant tasks with conflicting declared resources require a predecessor path. Cycles, missing predecessors, duplicate identities, and unordered read/write or write/write conflicts fail before accepted execution.

Each activation runs read → compute → enqueue. A due queued result runs write, after which the output remains held until another release. A zero-delay result can therefore write at its activation instant; a nonzero-delay result retains its originating sample index and exact release instant. Declared invalidations are applied only after a successful write.

State, rollback, restart, and results

The scheduler checkpoints the exact plan identity, current and last accepted tick, occurrence history, invalidation flags, and every task's state, next activation, counts, last sample/write tick, held output, pending queue and queue cursor. At a same-instant failure, AIMORA restores the EMT transaction, event state, shared owner, task state, queue, counts, occurrences, and output to the last accepted boundary. A corrupt or stale checkpoint is a typed refusal, never a partial restore.

EMTTaskResult reports acceptance or a typed EMTTaskPlatformFailure, plan and deterministic SHA-256 signatures, exact occurrences, activation counts, maximum pending depth, invalidations, and a final checkpoint. Failure diagnostics identify the task, family, exact instant, stage, code, message, and exact last accepted instant.

The public general_multirate_task_platform example executes sixteen period/phase combinations across all eight families. A 75 microsecond physical event collides with task activations and delayed releases; the final held output drives an existing EMT-controlled source. The example proves dependency order, event-first reads, delayed hold, exact split continuation, deterministic results, and full rollback after an injected callback failure.

Validity and exclusions

The scheduler's calendar and ordering are exact; task-owned numerical and physical uncertainty remains with each task. S210 supports deterministic serial Julia callbacks embedded in fixed-step instantaneous EMT. The example recurrences are synthetic and do not qualify protection, carrier/device, converter-control, machine, source, thermal, interface, or user equations.

This boundary does not provide parallel/preemptive dispatch, stochastic tasks, adaptive global stepping, partition coupling, portable cross-process snapshots, FMI, HELICS, IEC 61850, ATP, or PSCAD compatibility, asynchronous wall-clock callbacks, hard-real-time deadlines, HIL, network-protocol timing, GPU dispatch, safety properties, standard conformance, or certification. Later capabilities must preserve S210's exact logical order while qualifying those separate domains independently.