Module flight_metrics 

What a flight metric measures, tool by tool and version by version, and what becomes of a metric whose event never happened (M2.2d1).

A reference names a quantity with a word: maxvelocity, deploymentvelocity, groundhitvelocity, optimumdelay. The same word can mean a different quantity in another tool, or in another version of the same tool (Loft lesson L80). So a metric is compared only through its Definition, looked up by definition for the Tool and version that produced the reference. A version whose meaning has not been measured has no definition, and its value is withheld rather than compared as if it meant what the newest version means.

OpenRocket 24.12’s definitions are measured, not read from its source (which is GPL): validation/oracles/openrocket/flights.py flies every configuration of the public designs and records each summary word beside the quantities of OpenRocket’s own time series it could mean. The record is validation/fixtures/ork/openrocket-flights.json, and a test holds each definition below to it on every complete flight (ADR-068).

A metric taken at an event that did not happen, such as the deployment speed of a flight whose parachute never opened, has no value. OpenRocket writes NaN for it. Loft scored it as 0 (Loft lesson L81). compare withholds it when neither flight had the event, and fails it when only one did; it is never scored.

use hpr_validate::flight_metrics::{
    Event, Failure, FlightMetric, MetricOutcome, ReferenceReading, Side, Tool, Withheld, compare,
};

let openrocket = Tool::OpenRocket { version: "24.12".to_owned() };
// OpenRocket's Chute release example with a G40W-7: its last parachute opens at 14.2306 m/s.
let reading = ReferenceReading::Complete(Some(14.2306));
let outcome = compare(&openrocket, FlightMetric::DeploymentSpeed, reading, Some(14.0));
assert!((outcome.difference().unwrap() + 0.2306).abs() < 1e-9);

// No parachute opened in OpenRocket's flight (it wrote `NaN`), nor in hpr's: withheld.
let none = ReferenceReading::Complete(Some(f64::NAN));
assert_eq!(
    compare(&openrocket, FlightMetric::DeploymentSpeed, none, None),
    MetricOutcome::Withheld(Withheld::NoEventInEither { event: Event::Deployment })
);
// Only hpr's opened: a disagreement, which fails rather than being scored against 0.
assert_eq!(
    compare(&openrocket, FlightMetric::DeploymentSpeed, none, Some(9.0)),
    MetricOutcome::Failed(Failure::EventOnlyIn { event: Event::Deployment, side: Side::Measured })
);

Enums

Definition

What a metric measures, precisely enough to take it from a flight’s time series.

Event

An event in a flight that a metric is taken at.

Failure

Why a metric fails without being scored: the two flights disagree about what happened, or a value is broken.

FlightMetric

A summary quantity of one flight.

MetricOutcome

A metric compared, withheld, or failed. Never a zero standing in for a missing value.

Occurrence

Which occurrence of an event that can happen more than once.

Point

The point on the rocket whose height or speed a metric takes.

ReferenceReading

A reference flight’s value for one metric.

Side

One of the two flights compared.

Tool

A tool that produced a reference flight, with its version as the tool writes it.

Withheld

Why a metric was not compared, when that is no fault of either flight.

Constants

OPENROCKET_MEASURED

The OpenRocket version whose summary words flights.py measured.

ROCKETPY_MEASURED

The RocketPy version whose metrics hpr’s whole-flight cases compare against. Its definitions come from ADR-021, which read what RocketPy computes, not from a probe like flights.py.

Functions

compare

Compares hpr’s measured value of metric with a reference reading from tool.

definition

What metric measures in a reference from tool, or None where that has not been measured for the tool’s version.