Files
Aura/fieldtests/cycle-0008-sum-combinators/c0008_3_lincomb_three_legs.rs
T
Brummel 90e298d3b4 fieldtest: cycle-0008 — 5 examples, 6 findings
First fieldtest of the sum combinators. A standalone downstream-consumer crate
(fieldtests/cycle-0008-sum-combinators/) path-depends on the engine crates and
exercises the post-0008 surface from the public interface only (rustdoc + ledger
+ glossary + project-layout, never crates/*/src).

Primary axis empirically met: the north-star two-signal combine move now uses the
shipped Add (Add::new() dropped in exactly where the 0007 fixture hand-authored
an Add2) — the 0007 boilerplate is retired, end to end through SimBroker to a
deterministic recorded pip curve.

Findings: 0 bugs, 1 friction, 2 spec_gaps, 3 working.
  - working ×3: Add2 retired; LinComb weighted/variadic sums exact (<1e-12);
    warm-up barrier + empty-weights panic as documented.
  - spec_gap: Add/LinComb per-input firing policy (Firing::Any / mode-A as-of
    join) absent from the public surface — same class as the 0007 SimBroker gap.
  - spec_gap: a fired combinator emits one row per *cycle*, so a heterogeneous
    same-timestamp multi-source trace can carry >1 row per timestamp (correct per
    C4/C5, undocumented at this surface).
  - friction: nested consumer crate still needs the empty [workspace] table
    (carried from 0006/0007; #9 closed the docs half; folds into aura new).

Spec feeds the next plan as reference.
2026-06-04 18:21:57 +02:00

103 lines
3.9 KiB
Rust

//! Example 3 — the variadic-arity case: `LinComb` over N>2 signal legs.
//!
//! Three moving averages combined with weights [0.5, 0.3, 0.2]. Verifies the
//! arity is fixed by `weights.len()` (3 input slots), and that the recorded
//! output equals the 3-leg weighted sum on every fired cycle. Also confirms
//! the firing barrier: LinComb withholds output until ALL THREE legs warm up
//! (i.e. until the slowest, Sma(4), produces a value).
mod recorder;
use std::cell::RefCell;
use std::rc::Rc;
use aura_core::ScalarKind;
use aura_core::{Scalar, Timestamp};
use aura_engine::{Edge, Harness, SourceSpec, Target};
use aura_std::{LinComb, Sma};
use recorder::{Recorder, Tape};
fn main() {
const SMA2: usize = 0;
const SMA3: usize = 1;
const SMA4: usize = 2;
const LINCOMB: usize = 3;
const REC2: usize = 4;
const REC3: usize = 5;
const REC4: usize = 6;
const REC_OUT: usize = 7;
let t2: Tape = Rc::new(RefCell::new(Vec::new()));
let t3: Tape = Rc::new(RefCell::new(Vec::new()));
let t4: Tape = Rc::new(RefCell::new(Vec::new()));
let tout: Tape = Rc::new(RefCell::new(Vec::new()));
let weights = vec![0.5, 0.3, 0.2];
let nodes: Vec<Box<dyn aura_core::Node>> = vec![
Box::new(Sma::new(2)),
Box::new(Sma::new(3)),
Box::new(Sma::new(4)),
Box::new(LinComb::new(weights.clone())),
Box::new(Recorder::new(t2.clone())),
Box::new(Recorder::new(t3.clone())),
Box::new(Recorder::new(t4.clone())),
Box::new(Recorder::new(tout.clone())),
];
let sources = vec![SourceSpec {
kind: ScalarKind::F64,
targets: vec![
Target { node: SMA2, slot: 0 },
Target { node: SMA3, slot: 0 },
Target { node: SMA4, slot: 0 },
],
}];
let edges = vec![
Edge { from: SMA2, to: LINCOMB, slot: 0, from_field: 0 },
Edge { from: SMA3, to: LINCOMB, slot: 1, from_field: 0 },
Edge { from: SMA4, to: LINCOMB, slot: 2, from_field: 0 },
Edge { from: SMA2, to: REC2, slot: 0, from_field: 0 },
Edge { from: SMA3, to: REC3, slot: 0, from_field: 0 },
Edge { from: SMA4, to: REC4, slot: 0, from_field: 0 },
Edge { from: LINCOMB, to: REC_OUT, slot: 0, from_field: 0 },
];
let mut harness = Harness::bootstrap(nodes, sources, edges).expect("bootstrap");
let prices: &[f64] = &[10.0, 12.0, 14.0, 16.0, 18.0, 20.0, 22.0];
let stream: Vec<(Timestamp, Scalar)> = prices
.iter()
.enumerate()
.map(|(i, &p)| (Timestamp(i as i64), Scalar::F64(p)))
.collect();
harness.run(vec![stream]);
let (a, b, c, out) = (t2.borrow(), t3.borrow(), t4.borrow(), tout.borrow());
println!("sma2 rows={}, sma3 rows={}, sma4 rows={}, lincomb rows={}", a.len(), b.len(), c.len(), out.len());
// Sma(4) warms up last (needs 4 samples -> first value at t=3), so the 3-leg
// barrier means LinComb's first output is at t=3.
let first_out_ts = out.first().map(|&(t, _)| t.0);
println!("LinComb first fires at t={:?} (expect t=3, the slowest leg's warm-up)", first_out_ts);
assert_eq!(first_out_ts, Some(3), "3-leg warm-up barrier");
println!("\n t sma2 sma3 sma4 lincomb expected(0.5,0.3,0.2)");
for &(ts, combined) in out.iter() {
let s2 = a.iter().find(|&&(t, _)| t == ts).map(|&(_, v)| v).unwrap();
let s3 = b.iter().find(|&&(t, _)| t == ts).map(|&(_, v)| v).unwrap();
let s4 = c.iter().find(|&&(t, _)| t == ts).map(|&(_, v)| v).unwrap();
let expected = 0.5 * s2 + 0.3 * s3 + 0.2 * s4;
let ok = (combined - expected).abs() < 1e-12;
println!(
" {:>2} {:>7.3} {:>7.3} {:>7.3} {:>8.4} {:>8.4} {}",
ts.0, s2, s3, s4, combined, expected, if ok { "OK" } else { "MISMATCH" }
);
assert!(ok, "3-leg weighted sum mismatch at t={}", ts.0);
}
println!("\nall 3-leg weighted sums match = OK");
}