Put the pecos-neo composite noise DSL behind a composite-noise feature and delete the compiled-primitive prototype

.github/workflows/rust-test.yml

@@ -168,6 +168,7 @@ jobs:
             echo "Testing $crate..."
             cd "crates/$crate" && cargo clippy --locked --all-targets -- -D warnings && cd ../..
           done
+          cargo clippy --locked -p pecos-neo --lib -- -D warnings
           echo "Testing pecos without default features..."
           cd crates/pecos && cargo clippy --locked --all-targets --no-default-features -- -D warnings && cd ../..
 

docs/experimental/composable-noise.md

@@ -1,5 +1,7 @@
 # Composable Noise Models (pecos-neo)
 
+Enable the `composite-noise` Cargo feature on `pecos-neo` to use composite noise primitives and patterns.
+
 > This covers the Rust composable noise API in `pecos-neo`. For the Python noise builder API, see [Noise Model Builders](../user-guide/noise-model-builders.md).
 >
 > Source: `exp/pecos-neo/src/noise/`

exp/pecos-neo/Cargo.toml

@@ -39,14 +39,15 @@ pecos-qasm.workspace = true
 criterion.workspace = true
 proptest = "1.4"
 # Enable our own features for doctests and integration tests
-pecos-neo = { path = ".", features = ["qasm"] }
+pecos-neo = { path = ".", features = ["qasm", "composite-noise"] }
 
 [[bench]]
 name = "hot_path"
 harness = false
 
 [features]
 default = []
+composite-noise = []
 qasm = ["dep:pecos-qasm"]
 
 [lints]

exp/pecos-neo/README.md

@@ -42,3 +42,10 @@ for outcome in &results.outcomes {
 ## Documentation
 
 See the [full documentation](docs/README.md) for examples, guides, and reference material.
+
+## Cargo features
+
+Both features are off by default.
+
+- `qasm`: QASM program support.
+- `composite-noise`: Composite noise decision-tree primitives, builders, and patterns.

exp/pecos-neo/benches/hot_path.rs

@@ -1227,87 +1227,6 @@ fn bench_batch_processor(c: &mut Criterion) {
     group.finish();
 }
 
-/// Compare trait object dispatch vs compiled enum dispatch for composite primitives
-fn bench_dispatch_comparison(c: &mut Criterion) {
-    use pecos_neo::noise::NoiseContext;
-    use pecos_neo::noise::composite::prelude::*;
-    use pecos_neo::noise::composite::{CompiledAction, CompiledCondition, CompiledPrimitive};
-
-    let mut group = c.benchmark_group("dispatch_comparison");
-
-    // Create equivalent noise trees: trait-object and compiled versions
-
-    // Simple probability + pauli
-    let trait_simple: Box<dyn Primitive> = Box::new(prob(0.01, pauli()));
-    let compiled_simple = CompiledPrimitive::prob(
-        0.01,
-        CompiledPrimitive::action(CompiledAction::Pauli(PauliWeights::uniform())),
-    );
-
-    // More complex tree with conditions
-    let trait_complex = seq![skip_if_leaked(), prob(0.01, when_leaked(seep(), pauli())),];
-    let compiled_complex = CompiledPrimitive::seq(vec![
-        CompiledPrimitive::skip_if(CompiledCondition::Leaked),
-        CompiledPrimitive::prob(
-            0.01,
-            CompiledPrimitive::when(
-                CompiledCondition::Leaked,
-                CompiledPrimitive::action(CompiledAction::Seep(PauliWeights::uniform())),
-                CompiledPrimitive::action(CompiledAction::Pauli(PauliWeights::uniform())),
-            ),
-        ),
-    ]);
-
-    // Benchmark simple tree
-    group.bench_function("trait_simple_pauli", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| black_box(trait_simple.apply(QubitId(0), &mut ctx, &mut rng)));
-    });
-
-    group.bench_function("compiled_simple_pauli", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| black_box(compiled_simple.apply(QubitId(0), &mut ctx, &mut rng)));
-    });
-
-    // Benchmark complex tree
-    group.bench_function("trait_complex_tree", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| black_box(trait_complex.apply(QubitId(0), &mut ctx, &mut rng)));
-    });
-
-    group.bench_function("compiled_complex_tree", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| black_box(compiled_complex.apply(QubitId(0), &mut ctx, &mut rng)));
-    });
-
-    // Benchmark many iterations to amortize setup
-    group.bench_function("trait_1000_iterations", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| {
-            for _ in 0..1000 {
-                black_box(trait_complex.apply(QubitId(0), &mut ctx, &mut rng));
-            }
-        });
-    });
-
-    group.bench_function("compiled_1000_iterations", |b| {
-        let mut ctx = NoiseContext::new();
-        let mut rng = PecosRng::seed_from_u64(42);
-        b.iter(|| {
-            for _ in 0..1000 {
-                black_box(compiled_complex.apply(QubitId(0), &mut ctx, &mut rng));
-            }
-        });
-    });
-
-    group.finish();
-}
-
 criterion_group!(
     benches,
     bench_noise_emission,
@@ -1322,7 +1241,6 @@ criterion_group!(
     bench_composite_vs_channel_noise,
     bench_batch_filtering,
     bench_batch_processor,
-    bench_dispatch_comparison,
 );
 
 criterion_main!(benches);

exp/pecos-neo/docs/design/noise-composite.md

@@ -16,7 +16,6 @@
 | CompositeChannel integration | Complete | `composite/channel.rs` |
 | CompositeNoiseModelBuilder | Complete | `composite/builder.rs` |
 | Geometric sampling optimization | Complete | `composite/batch.rs` |
-| Compiled primitives | Complete | `composite/compiled.rs` |
 | Crosstalk channel | Complete | `composite/channel.rs` |
 | Two-stage primitives | Complete | `composite/primitive.rs` |
 
@@ -399,13 +398,6 @@ for i in fault_mask.iter_ones() {
 }
 ```
 
-### Compilation
-
-Primitive trees can compile to optimized code:
-- Eliminate virtual dispatch
-- Inline small actions
-- Optimal branch ordering
-
 ## Visualization
 
 Multiple views for different needs:
@@ -470,7 +462,7 @@ This design relates to existing pecos-neo infrastructure:
 | `GeneralNoiseModelBuilder` | A preset that builds primitive trees |
 
 Options:
-1. **Internal implementation**: Primitives compile to existing channel interface
+1. **Internal implementation**: Primitives integrate through the existing channel interface
 2. **Alternative API**: New way to build models, coexists with channels
 3. **Replacement**: Migrate to primitives, deprecate channels
 
@@ -489,7 +481,7 @@ Recommendation: Start with option 1 (internal), validate the design works.
 |------|----------|
 | **Constrained** | Small fixed primitive set |
 | **Grounded** | Primitives map to physical processes |
-| **Fast** | Early exit, RNG batching, compilation |
+| **Fast** | Early exit, RNG batching |
 | **Flexible** | Primitives compose freely |
 | **Understandable** | Trees visualize as flowcharts |
 | **Tricky cases** | Outcome primitives + Crosstalk special construct |
@@ -562,7 +554,6 @@ crates/pecos-neo/src/noise/
 
 **Deliverables:**
 - Geometric sampling for batch processing: Complete (`composite/batch.rs`)
-- Tree compilation: Complete (`composite/compiled.rs`)
 - RNG batching: Complete (`GeometricSampler`)
 - Benchmarks: Available in `benches/hot_path.rs`
 

exp/pecos-neo/docs/dev/noise.md

@@ -1,5 +1,7 @@
 # Noise System Usage Guide
 
+Composite decision-tree APIs require the `composite-noise` Cargo feature on `pecos-neo`.
+
 This guide covers practical usage of the pecos-neo noise modeling system.
 
 ## Overview
@@ -310,17 +312,6 @@ let channel = CompositeChannel::new("fast_depol", prob(0.001, depolarize()))
     .with_filter(CompositeEventFilter::SingleQubitGate);
 ```
 
-### Compiled Primitives
-
-Complex primitive trees can be compiled for better performance:
-
-```rust
-use pecos_neo::noise::composite::compiled::CompiledPrimitive;
-
-let primitive = seq(vec![...]);
-let compiled = CompiledPrimitive::compile(&primitive);
-```
-
 ## Debugging Noise Models
 
 ### Introspection

exp/pecos-neo/docs/user-guides/noise.md

@@ -1,5 +1,7 @@
 # Adding Noise
 
+Enable the `composite-noise` Cargo feature on `pecos-neo` to use composite noise primitives and patterns.
+
 ## Quickest Option
 
 One-liner on `sim_neo`:

exp/pecos-neo/src/noise.rs

@@ -19,6 +19,8 @@
 //! - **Composed**: Build decision trees using primitives (prob, when, seq, etc.)
 //! - **Custom**: Implement your own channels for complete control
 //!
+//! Decision-tree primitives are available with the `composite-noise` Cargo feature.
+//!
 //! # Quick Start
 //!
 //! Import everything with the prelude:
@@ -32,13 +34,6 @@
 //!     .with_measurement_error(0.02)
 //!     .build();
 //!
-//! // Composed: build custom decision trees
-//! let composed = NoiseModelBuilder::new()
-//!     .with_single_qubit_noise(seq![
-//!         skip_if_leaked(),
-//!         prob(0.001, when_leaked(seep(), pauli())),
-//!     ])
-//!     .build();
 //! ```
 //!
 //! Mixed approach (combine builder with custom channels):
@@ -99,6 +94,7 @@
 pub mod builder;
 pub mod category_channel;
 pub mod composer;
+#[cfg(feature = "composite-noise")]
 pub mod composite;
 pub mod context;
 pub mod correlated;

exp/pecos-neo/src/noise/builder.rs

@@ -15,6 +15,8 @@
 //! This module provides [`NoiseModelBuilder`], the primary way to construct noise models.
 //! It unifies simple parameter-based configuration with composable channel construction.
 //!
+//! Decision-tree construction requires the `composite-noise` Cargo feature.
+//!
 //! # Philosophy
 //!
 //! The noise system is built on a few key concepts:
@@ -34,26 +36,16 @@
 //!     .with_measurement_error(0.02)
 //!     .build();
 //!
-//! // Composed: build custom decision trees
-//! let composed = NoiseModelBuilder::new()
-//!     .with_single_qubit_noise(seq![
-//!         skip_if_leaked(),
-//!         prob(0.001, when_leaked(seep(), pauli())),
-//!     ])
-//!     .with_two_qubit_noise(seq![
-//!         skip_if_leaked(),
-//!         prob(0.01, two_qubit_pauli()),
-//!     ])
-//!     .build();
-//!
 //! // Mixed: combine both approaches
 //! let mixed = NoiseModelBuilder::new()
 //!     .with_depolarizing(0.001, 0.01)  // Simple base rates
 //!     .with_channel(LeakageChannel::new())  // Add custom channel
 //!     .build();
 //! ```
 
+#[cfg(feature = "composite-noise")]
 use super::composite::Primitive;
+#[cfg(feature = "composite-noise")]
 use super::composite::channel::{CompositeChannel, CompositeChannelBuilder};
 use super::crosstalk::CrosstalkChannel;
 use super::idle::IdleChannel;
@@ -90,19 +82,6 @@ use pecos_core::TimeScale;
 ///     .build();
 /// ```
 ///
-/// ## Custom composed noise
-///
-/// ```
-/// use pecos_neo::noise::prelude::*;
-///
-/// let model = NoiseModelBuilder::new()
-///     .with_single_qubit_noise(seq![
-///         skip_if_leaked(),
-///         prob(0.001, pauli()),
-///     ])
-///     .build();
-/// ```
-///
 /// ## Adding existing channels
 ///
 /// ```
@@ -413,7 +392,21 @@ impl NoiseModelBuilder {
     ///     ])
     ///     .build();
     /// ```
+    ///
+    /// ## Custom composed noise
+    ///
+    /// ```
+    /// use pecos_neo::noise::prelude::*;
+    ///
+    /// let model = NoiseModelBuilder::new()
+    ///     .with_single_qubit_noise(seq![
+    ///         skip_if_leaked(),
+    ///         prob(0.001, pauli()),
+    ///     ])
+    ///     .build();
+    /// ```
     #[must_use]
+    #[cfg(feature = "composite-noise")]
     pub fn with_single_qubit_noise<P: Primitive + Clone + 'static>(mut self, primitive: P) -> Self {
         let channel = CompositeChannelBuilder::single_qubit("single_qubit", primitive);
         self.custom_channels.push(Box::new(channel));
@@ -425,6 +418,7 @@ impl NoiseModelBuilder {
     ///
     /// This overrides the simple p2-based configuration.
     #[must_use]
+    #[cfg(feature = "composite-noise")]
     pub fn with_two_qubit_noise<P: Primitive + Clone + 'static>(mut self, primitive: P) -> Self {
         let channel = CompositeChannelBuilder::two_qubit("two_qubit", primitive);
         self.custom_channels.push(Box::new(channel));
@@ -436,6 +430,7 @@ impl NoiseModelBuilder {
     ///
     /// This overrides the simple p_meas-based configuration.
     #[must_use]
+    #[cfg(feature = "composite-noise")]
     pub fn with_measurement_noise<P: Primitive + Clone + 'static>(mut self, primitive: P) -> Self {
         let channel = CompositeChannelBuilder::after_measurement("measurement", primitive);
         self.custom_channels.push(Box::new(channel));
@@ -447,6 +442,7 @@ impl NoiseModelBuilder {
     ///
     /// This overrides the simple p_prep-based configuration.
     #[must_use]
+    #[cfg(feature = "composite-noise")]
     pub fn with_preparation_noise<P: Primitive + Clone + 'static>(mut self, primitive: P) -> Self {
         let channel = CompositeChannelBuilder::preparation("preparation", primitive);
         self.custom_channels.push(Box::new(channel));
@@ -471,6 +467,7 @@ impl NoiseModelBuilder {
     ///     .build();
     /// ```
     #[must_use]
+    #[cfg(feature = "composite-noise")]
     pub fn with_custom_channel<P: Primitive + Clone + 'static>(
         mut self,
         channel: CompositeChannel<P>,

exp/pecos-neo/src/noise/composite.rs

@@ -159,7 +159,6 @@ pub mod batch;
 pub mod batch_composite;
 mod builder;
 pub mod channel;
-mod compiled;
 mod condition;
 mod primitive;
 mod response;
@@ -176,7 +175,6 @@ pub use channel::{
     BatchCompositeChannel, CompositeChannel, CompositeChannelBuilder, CompositeCrosstalkChannel,
     CompositeEventFilter,
 };
-pub use compiled::{CompiledAction, CompiledCondition, CompiledPrimitive};
 pub use condition::{
     Active, Always, AnyQubitLeaked, Condition, FnCondition, GateTypeIs, Leaked, Never, NotLeaked,
     OutcomeIs, PartnerLeaked,