Struct IsStable 

pub struct IsStable {
    pub margin: f64,
    pub min_samples: u64,
    /* private fields */
}

The settled level and the steady-state signal of a window of samples.

Signature: is_stable(samples: vec_f64, margin: f64, min_samples: u64) -> (stable_value: f64, stable: u64)

• stable_value is the median of samples: a central estimate that one outlier, such as a trailing empty-window sample, barely moves. An empty window reports 0.0.
• stable is 1 when the window holds at least min_samples samples and their standard deviation is within margin · max(|median|, 1), a relative band with an absolute floor so a level near zero still settles; otherwise 0.

The host owns the window: it appends each new sample and drops the oldest, and writes the window as an input before it reads. The cost is linear in the window’s length and is paid only when the window changes, so it scales with how often the host updates the window, not with how often samples arrive. A host whose samples arrive much faster than it needs to decide should aggregate them into the window rather than pass every one.

Fields

margin: f64

The margin argument, as given at construction.

min_samples: u64

The min_samples argument, as given at construction.

Implementations

impl IsStable

pub fn new(margin: f64, min_samples: u64) -> Self

A is_stable node with the given constant arguments.

Trait Implementations

impl PolydatNode for IsStable

fn meta(&self) -> &NodeMeta

Return this node’s metadata (port names and types).

fn eval(&self, inputs: &[Value], outputs: &mut [Value])

Evaluate the node: read from inputs, write to outputs.

fn compiled_slot( &self, wire_types: &[PortType], _engine: Engine, ) -> Option<CompiledSlotKit>

Return a slot-compiled closure for nodes with typed-slice ports (§8.4 layer 3): slice inputs read (ptr, len) slot pairs; vector outputs write into kernel-owned scratch. Checked by the compiled-kernel builders AFTER Self::compiled_u64 — pure-scalar nodes never need it. Default None: the node stays on typed eval.

fn scratch_layout(&self) -> Vec<ScratchElem>

The scratch entries a state owns for this node’s evaluation (axiom S3), one per entry in the order the node expects them in Self::eval_in. Empty for a node that evaluates over Values alone, which is every node but a native cone.

fn eval_in( &self, scratch: &mut [ScratchBuf], inputs: &[Value], outputs: &mut [Value], )

Self::eval with the node’s scratch, which the evaluating state owns and hands in: storage belongs to the state, never to the node, which is shared by every state of the program.

fn commutativity(&self) -> Commutativity

Declare which inputs are interchangeable for this node.

fn accepts_none_inputs(&self) -> bool

True iff this node should receive Value::None inputs directly rather than have the kernel propagate None through it. Default: false — most nodes follow none_semantics.md Rule 1 (None in → None out, no eval invocation).

fn compiled_u64(&self) -> Option<Box<dyn Fn(&[u64], &mut [u64]) + Send + Sync>>

Return a compiled u64-only evaluation closure, if this node operates entirely in u64 space.

fn jit_constants(&self) -> Vec<u64>

Return assembly-time constants for JIT compilation.

fn purity(&self) -> Purity

Declare this node’s purity status per the runtime_model.md’s D2 axiom. Default: Purity::Pure. Override to declare an observable side channel (Purity::SideChannel) or eval-call-spanning state (Purity::Nondeterministic).

fn simd_variant(&self) -> Option<SimdVariant>

Explicit SIMD-native implementation of this scalar node, if one has been registered with a semantic contract.

fn fusion_subgraph(&self) -> Option<FusionSubgraph<'_>>

A synthetic fusion node’s view of the subgraph it stands in for (cone extraction, engines.md §2). Program-identity hashing (PolydatProgram::canonical_hash) walks THROUGH fusion nodes into this subgraph, so identity is invariant to the engine mix: jit=off and jit=auto compiles of the same source hash identically, and resume-skip matching survives mode changes. Default None: ordinary nodes hash as themselves.