Files
Aura/crates/aura-std/src/max.rs
T
claude a32dc38d18 feat(std): meaning lines for all 27 shipped node schemas
C29 compile/unit seam, task 3 of the self-description plan: every
aura-std NodeSchema literal threads its one-line doc. Four texts were
corrected against the actual eval/finalize semantics rather than taken
from the plan table verbatim: Delay is a lag-N register (not one-step),
GatedRecorder flushes an ungated final row at finalize, Latch is a
level-sensitive set/reset register (captures no input), SeriesReducer
emits its single summary row at finalize (not per cycle).

Gate: cargo build -p aura-std --lib clean; full std test run follows at
the all-crates gate once strategy/backtest/engine thread their sites
(the earlier per-crate test gate was unsatisfiable in isolation --
std's dev-deps pull crates whose sites belong to later tasks).

refs #316
2026-07-23 15:25:16 +02:00

90 lines
2.6 KiB
Rust

//! `Max` — two-input f64 pairwise maximum (input 0 vs input 1), e.g. the
//! positive-part split of a price change: `gain = Max(delta, 0)`. Distinct
//! from `RollingMax`, which reduces a *window* of one input; `Max` combines
//! two co-present inputs, mirroring `Add`/`Sub`.
use aura_core::{Cell, Ctx, FieldSpec, Firing, Node, NodeSchema, PortSpec, PrimitiveBuilder, ScalarKind};
/// Two-input f64 pairwise maximum: `input 0 .max(input 1)`. Emits `None` until
/// both inputs have a value.
pub struct Max {
out: [Cell; 1],
}
impl Max {
pub fn new() -> Self {
Self { out: [Cell::from_f64(0.0)] }
}
pub fn builder() -> PrimitiveBuilder {
PrimitiveBuilder::new(
"Max",
NodeSchema {
inputs: vec![
PortSpec { kind: ScalarKind::F64, firing: Firing::Any, name: "lhs".into() },
PortSpec { kind: ScalarKind::F64, firing: Firing::Any, name: "rhs".into() },
],
output: vec![FieldSpec { name: "value".into(), kind: ScalarKind::F64 }],
params: vec![],
doc: "elementwise maximum of two input series",
},
|_| Box::new(Max::new()),
)
}
}
impl Default for Max {
fn default() -> Self {
Self::new()
}
}
impl Node for Max {
fn lookbacks(&self) -> Vec<usize> {
vec![1, 1]
}
fn eval(&mut self, ctx: Ctx<'_>) -> Option<&[Cell]> {
let a = ctx.f64_in(0);
let b = ctx.f64_in(1);
if a.is_empty() || b.is_empty() {
return None;
}
self.out[0] = Cell::from_f64(a[0].max(b[0]));
Some(&self.out)
}
fn label(&self) -> String {
"Max".to_string()
}
}
#[cfg(test)]
mod tests {
use super::*;
use aura_core::{AnyColumn, Scalar, Timestamp};
#[test]
fn max_is_the_pairwise_larger_once_both_inputs_present() {
let mut m = Max::new();
let mut inputs = vec![
AnyColumn::with_capacity(ScalarKind::F64, 1),
AnyColumn::with_capacity(ScalarKind::F64, 1),
];
// only input 0 present -> None
inputs[0].push(Scalar::f64(2.0)).unwrap();
assert_eq!(m.eval(Ctx::new(&inputs, Timestamp(0))), None);
// both present -> max(a, b), either order
inputs[1].push(Scalar::f64(-1.0)).unwrap();
assert_eq!(m.eval(Ctx::new(&inputs, Timestamp(0))), Some([Cell::from_f64(2.0)].as_slice()));
}
#[test]
fn input_slots_are_named_lhs_rhs() {
let names: Vec<String> = Max::builder().schema().inputs.iter().map(|p| p.name.clone()).collect();
assert_eq!(names, ["lhs", "rhs"]);
}
}