Generators

Generators produce member values each tick. Miravo ships 18 generator types organized into three categories.

Source Generators

These produce values from their own configuration without requiring input from other members.

sine

Sinusoidal oscillation with optional noise.

generator:
  type: sine
  center: 1750        # Supports $param.X
  amplitude: 50
  period: 3600
  noise: 0.01

Formula: center + amplitude * sin(2 * pi * t / period) + N(0, noise * |center|)

noise

Gaussian noise around a center value.

generator:
  type: noise
  center: 22.0        # Supports $param.X
  stddev: 0.5

Formula: center + N(0, stddev)

random-walk

Bounded random walk. Stateful — remembers position between ticks.

generator:
  type: random-walk
  min: 0
  max: 100
  step: 0.5

step

Cycles through a list of values at fixed intervals. Fully deterministic, no RNG.

generator:
  type: step
  values: [0, 25, 50, 75, 100]
  interval: 60

ramp

Linear trajectory from a start value. Holds after duration.

generator:
  type: ramp
  start_value: 0
  rate: 10
  duration: 300

mean-reverting-noise

Ornstein-Uhlenbeck process. Bounded variance unlike random-walk.

generator:
  type: mean-reverting-noise
  mean: 50            # Supports $param.X
  tau: 10
  sigma: 2.0

Formula: value = mean + alpha * (prev - mean) + sigma * sqrt(1 - alpha^2) * N(0, 1) where alpha = exp(-dt / tau)

timetable

Piecewise interpolation over time-value waypoints. Supports linear and step interpolation.

generator:
  type: timetable
  repeat: true
  interpolation: step
  points:
    - { time: 0, value: 0 }
    - { time: 21600, value: 1200 }
    - { time: 64800, value: 900 }
    - { time: 86400, value: 0 }

state-machine

Probabilistic state transitions. Stateful.

generator:
  type: state-machine
  initial: "idle"
  transitions:
    - from: idle
      to: running
      probability: 0.1
    - from: running
      to: idle
      probability: 0.05
    - from: running
      to: faulted
      on: fault

The on: "fault" trigger fires only when the instance has active faults.

Dynamic Generators

These transform input from other members, parameters, or inline sub-generators.

Input Resolution

All dynamic generators accept an input field:

input: { member: "speed_feedback" }    # Read from an earlier member
input: { param: "rated_rpm" }          # Read from a parameter
input: { generator: { type: noise, center: 50, stddev: 1 } }  # Inline sub-generator

first-order-lag

PT1 low-pass filter. Models thermal lag, sensor response.

generator:
  type: first-order-lag
  tau: 30
  gain: 1.0             # Supports $param.X
  bias: 0               # Supports $param.X
  input: { member: "speed_feedback" }

integrator

Accumulator with clamp or wrap. Models runtime hours, tank levels, energy totals.

generator:
  type: integrator
  gain: 0.000278
  bias_rate: 0
  clamp: [0, 100000]
  input: { member: "power_draw" }

transport-delay

Delays input by a configurable time. Ring buffer with interpolation.

generator:
  type: transport-delay
  delay: 15              # Supports $param.X
  interpolation: linear
  input: { member: "entry_signal" }

slew-rate-limiter

Limits rate of change with asymmetric up/down rates.

generator:
  type: slew-rate-limiter
  rate_up: 100
  rate_down: 50
  input: { member: "speed_command" }

second-order

Second-order dynamic response. Models underdamped overshoot or overdamped settling.

generator:
  type: second-order
  omega_n: 0.5
  zeta: 0.3
  gain: 1.0              # Supports $param.X
  bias: 0                # Supports $param.X
  input: { member: "load_setpoint" }

hysteresis-relay

Two-threshold switching with dead band. String or numeric output.

generator:
  type: hysteresis-relay
  threshold_rising: 8.5    # Supports $param.X
  threshold_falling: 7.5   # Supports $param.X
  output_high: 1
  output_low: 0
  input: { member: "header_pressure" }

weighted-sum

Linear combination of multiple inputs.

generator:
  type: weighted-sum
  bias: 0                  # Supports $param.X
  terms:
    - input: { member: "inflow_rate" }
      weight: 1.0          # Supports $param.X
    - input: { member: "outflow_rate" }
      weight: -1.0

gate

Passes input through only when a Boolean member is true. Used for run/stop gating.

generator:
  type: gate
  enabled_member: running
  disabled_value: 0
  input: { member: "speed_command" }

Composite Generators

correlated

Derives a value from another member with a linear transform.

generator:
  type: correlated
  source: speed_feedback
  factor: 0.008          # Supports $param.X
  offset: 2.0            # Supports $param.X
  noise: 0.02

Formula: factor * source + offset + N(0, noise * |base|)

The source member must be declared earlier in the model’s members map.

health-dependent

Delegates to different sub-generators based on the current lifecycle stage.

generator:
  type: health-dependent
  stages:
    healthy:
      type: noise
      center: 2.5
      stddev: 0.3
    degraded:
      type: noise
      center: 4.0
      stddev: 0.8
    critical:
      type: noise
      center: 7.0
      stddev: 1.5

Parameter References

Many generator fields support $param.X references. These resolve to the instance’s parameter value at runtime:

parameters:
  rated_rpm:
    type: float
    default: 1750

members:
  speed:
    kind: variable
    data_type: Double
    generator:
      type: noise
      center: "$param.rated_rpm"
      stddev: 5

Supported fields: center (sine, noise), mean (mean-reverting-noise), factor/offset (correlated), gain/bias (first-order-lag, second-order), delay (transport-delay), thresholds (hysteresis-relay), bias/weight (weighted-sum).