Enable avoiding Python operation creation in transpiler (Qiskit#12692)

* Avoid Python operation creation in transpiler

Since Qiskit#12459 accessing `node.op` in the transpiler eagerly creates a
Python object on access. This is because we now are no longer storing a
Python object internally and we need to rebuild the object to return the
python object as expected by the api. This is causing a significant
performance regression because of the extra overhead. The longer term
goal is to move as much of the performance critical passes to operate in
rust which will eliminate this overhead. But in the meantime we can
mitigate the performance overhead by changing the Python access patterns
to avoid the operation object creation. This commit adds some new getter
methods to DAGOpNode to give access to the inner rust data so that we
can avoid the extra overhead. As a proof of concept this updates the
unitary synthesis pass in isolation. Doing this fixes the regression
caused by Qiskit#12459 for that pass. We can continue this migration for
everything else in follow up PRs. This commit is mostly to establish the
pattern and add the python space access methods.

* Remove unused import

* Add path to avoid StandardGate conversion in circuit_to_dag

* Add fast path through dag_to_circuit

crates/circuit/src/circuit_data.rs

@@ -18,7 +18,7 @@ use crate::circuit_instruction::{
     convert_py_to_operation_type, CircuitInstruction, ExtraInstructionAttributes, OperationInput,
     PackedInstruction,
 };
-use crate::imports::{BUILTIN_LIST, QUBIT};
+use crate::imports::{BUILTIN_LIST, DEEPCOPY, QUBIT};
 use crate::interner::{IndexedInterner, Interner, InternerKey};
 use crate::operations::{Operation, OperationType, Param, StandardGate};
 use crate::parameter_table::{ParamEntry, ParamTable, GLOBAL_PHASE_INDEX};
@@ -488,20 +488,17 @@ impl CircuitData {
         res.param_table.clone_from(&self.param_table);
 
         if deepcopy {
-            let deepcopy = py
-                .import_bound(intern!(py, "copy"))?
-                .getattr(intern!(py, "deepcopy"))?;
             for inst in &mut res.data {
                 match &mut inst.op {
                     OperationType::Standard(_) => {}
                     OperationType::Gate(ref mut op) => {
-                        op.gate = deepcopy.call1((&op.gate,))?.unbind();
+                        op.gate = DEEPCOPY.get_bound(py).call1((&op.gate,))?.unbind();
                     }
                     OperationType::Instruction(ref mut op) => {
-                        op.instruction = deepcopy.call1((&op.instruction,))?.unbind();
+                        op.instruction = DEEPCOPY.get_bound(py).call1((&op.instruction,))?.unbind();
                     }
                     OperationType::Operation(ref mut op) => {
-                        op.operation = deepcopy.call1((&op.operation,))?.unbind();
+                        op.operation = DEEPCOPY.get_bound(py).call1((&op.operation,))?.unbind();
                     }
                 };
                 #[cfg(feature = "cache_pygates")]

crates/circuit/src/circuit_instruction.rs

@@ -13,6 +13,7 @@
 #[cfg(feature = "cache_pygates")]
 use std::cell::RefCell;
 
+use numpy::IntoPyArray;
 use pyo3::basic::CompareOp;
 use pyo3::exceptions::{PyDeprecationWarning, PyValueError};
 use pyo3::prelude::*;
@@ -25,7 +26,9 @@ use crate::imports::{
     SINGLETON_CONTROLLED_GATE, SINGLETON_GATE, WARNINGS_WARN,
 };
 use crate::interner::Index;
-use crate::operations::{OperationType, Param, PyGate, PyInstruction, PyOperation, StandardGate};
+use crate::operations::{
+    Operation, OperationType, Param, PyGate, PyInstruction, PyOperation, StandardGate,
+};
 
 /// These are extra mutable attributes for a circuit instruction's state. In general we don't
 /// typically deal with this in rust space and the majority of the time they're not used in Python
@@ -407,6 +410,56 @@ impl CircuitInstruction {
         })
     }
 
+    #[getter]
+    fn _raw_op(&self, py: Python) -> PyObject {
+        self.operation.clone().into_py(py)
+    }
+
+    /// Returns the Instruction name corresponding to the op for this node
+    #[getter]
+    fn get_name(&self, py: Python) -> PyObject {
+        self.operation.name().to_object(py)
+    }
+
+    #[getter]
+    fn get_params(&self, py: Python) -> PyObject {
+        self.params.to_object(py)
+    }
+
+    #[getter]
+    fn matrix(&self, py: Python) -> Option<PyObject> {
+        let matrix = self.operation.matrix(&self.params);
+        matrix.map(|mat| mat.into_pyarray_bound(py).into())
+    }
+
+    #[getter]
+    fn label(&self) -> Option<&str> {
+        self.extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.label.as_deref())
+    }
+
+    #[getter]
+    fn condition(&self, py: Python) -> Option<PyObject> {
+        self.extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.condition.as_ref().map(|x| x.clone_ref(py)))
+    }
+
+    #[getter]
+    fn duration(&self, py: Python) -> Option<PyObject> {
+        self.extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.duration.as_ref().map(|x| x.clone_ref(py)))
+    }
+
+    #[getter]
+    fn unit(&self) -> Option<&str> {
+        self.extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.unit.as_deref())
+    }
+
     /// Creates a shallow copy with the given fields replaced.
     ///
     /// Returns:

crates/circuit/src/dag_node.rs

@@ -15,9 +15,11 @@ use crate::circuit_instruction::{
     ExtraInstructionAttributes,
 };
 use crate::operations::Operation;
+use numpy::IntoPyArray;
 use pyo3::prelude::*;
 use pyo3::types::{PyDict, PyList, PySequence, PyString, PyTuple};
-use pyo3::{intern, PyObject, PyResult};
+use pyo3::{intern, IntoPy, PyObject, PyResult};
+use smallvec::smallvec;
 
 /// Parent class for DAGOpNode, DAGInNode, and DAGOutNode.
 #[pyclass(module = "qiskit._accelerate.circuit", subclass)]
@@ -70,12 +72,19 @@ pub struct DAGOpNode {
 
 #[pymethods]
 impl DAGOpNode {
+    #[allow(clippy::too_many_arguments)]
     #[new]
+    #[pyo3(signature = (op, qargs=None, cargs=None, params=smallvec![], label=None, duration=None, unit=None, condition=None, dag=None))]
     fn new(
         py: Python,
-        op: PyObject,
+        op: crate::circuit_instruction::OperationInput,
         qargs: Option<&Bound<PySequence>>,
         cargs: Option<&Bound<PySequence>>,
+        params: smallvec::SmallVec<[crate::operations::Param; 3]>,
+        label: Option<String>,
+        duration: Option<PyObject>,
+        unit: Option<String>,
+        condition: Option<PyObject>,
         dag: Option<&Bound<PyAny>>,
     ) -> PyResult<(Self, DAGNode)> {
         let qargs =
@@ -110,34 +119,16 @@ impl DAGOpNode {
             }
             None => qargs.str()?.into_any(),
         };
-        let res = convert_py_to_operation_type(py, op.clone_ref(py))?;
 
-        let extra_attrs = if res.label.is_some()
-            || res.duration.is_some()
-            || res.unit.is_some()
-            || res.condition.is_some()
-        {
-            Some(Box::new(ExtraInstructionAttributes {
-                label: res.label,
-                duration: res.duration,
-                unit: res.unit,
-                condition: res.condition,
-            }))
-        } else {
-            None
-        };
+        let mut instruction = CircuitInstruction::py_new(
+            py, op, None, None, params, label, duration, unit, condition,
+        )?;
+        instruction.qubits = qargs.into();
+        instruction.clbits = cargs.into();
 
         Ok((
             DAGOpNode {
-                instruction: CircuitInstruction {
-                    operation: res.operation,
-                    qubits: qargs.unbind(),
-                    clbits: cargs.unbind(),
-                    params: res.params,
-                    extra_attrs,
-                    #[cfg(feature = "cache_pygates")]
-                    py_op: Some(op),
-                },
+                instruction,
                 sort_key: sort_key.unbind(),
             },
             DAGNode { _node_id: -1 },
@@ -219,6 +210,77 @@ impl DAGOpNode {
         self.instruction.operation.name().to_object(py)
     }
 
+    #[getter]
+    fn get_params(&self, py: Python) -> PyObject {
+        self.instruction.params.to_object(py)
+    }
+
+    #[getter]
+    fn matrix(&self, py: Python) -> Option<PyObject> {
+        let matrix = self.instruction.operation.matrix(&self.instruction.params);
+        matrix.map(|mat| mat.into_pyarray_bound(py).into())
+    }
+
+    #[getter]
+    fn label(&self) -> Option<&str> {
+        self.instruction
+            .extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.label.as_deref())
+    }
+
+    #[getter]
+    fn condition(&self, py: Python) -> Option<PyObject> {
+        self.instruction
+            .extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.condition.as_ref().map(|x| x.clone_ref(py)))
+    }
+
+    #[getter]
+    fn duration(&self, py: Python) -> Option<PyObject> {
+        self.instruction
+            .extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.duration.as_ref().map(|x| x.clone_ref(py)))
+    }
+
+    #[getter]
+    fn unit(&self) -> Option<&str> {
+        self.instruction
+            .extra_attrs
+            .as_ref()
+            .and_then(|attrs| attrs.unit.as_deref())
+    }
+
+    #[setter]
+    fn set_label(&mut self, val: Option<String>) {
+        match self.instruction.extra_attrs.as_mut() {
+            Some(attrs) => attrs.label = val,
+            None => {
+                if val.is_some() {
+                    self.instruction.extra_attrs = Some(Box::new(
+                        crate::circuit_instruction::ExtraInstructionAttributes {
+                            label: val,
+                            duration: None,
+                            unit: None,
+                            condition: None,
+                        },
+                    ))
+                }
+            }
+        };
+        if let Some(attrs) = &self.instruction.extra_attrs {
+            if attrs.label.is_none()
+                && attrs.duration.is_none()
+                && attrs.unit.is_none()
+                && attrs.condition.is_none()
+            {
+                self.instruction.extra_attrs = None;
+            }
+        }
+    }
+
     /// Sets the Instruction name corresponding to the op for this node
     #[setter]
     fn set_name(&mut self, py: Python, new_name: PyObject) -> PyResult<()> {
@@ -229,6 +291,11 @@ impl DAGOpNode {
         Ok(())
     }
 
+    #[getter]
+    fn _raw_op(&self, py: Python) -> PyObject {
+        self.instruction.operation.clone().into_py(py)
+    }
+
     /// Returns a representation of the DAGOpNode
     fn __repr__(&self, py: Python) -> PyResult<String> {
         Ok(format!(

crates/circuit/src/imports.rs

@@ -71,6 +71,7 @@ pub static SINGLETON_GATE: ImportOnceCell =
     ImportOnceCell::new("qiskit.circuit.singleton", "SingletonGate");
 pub static SINGLETON_CONTROLLED_GATE: ImportOnceCell =
     ImportOnceCell::new("qiskit.circuit.singleton", "SingletonControlledGate");
+pub static DEEPCOPY: ImportOnceCell = ImportOnceCell::new("copy", "deepcopy");
 
 pub static WARNINGS_WARN: ImportOnceCell = ImportOnceCell::new("warnings", "warn");
 

crates/circuit/src/operations.rs

@@ -13,7 +13,7 @@
 use std::f64::consts::PI;
 
 use crate::circuit_data::CircuitData;
-use crate::imports::{PARAMETER_EXPRESSION, QUANTUM_CIRCUIT};
+use crate::imports::{DEEPCOPY, PARAMETER_EXPRESSION, QUANTUM_CIRCUIT};
 use crate::{gate_matrix, Qubit};
 
 use ndarray::{aview2, Array2};
@@ -35,6 +35,17 @@ pub enum OperationType {
     Operation(PyOperation),
 }
 
+impl IntoPy<PyObject> for OperationType {
+    fn into_py(self, py: Python) -> PyObject {
+        match self {
+            Self::Standard(gate) => gate.into_py(py),
+            Self::Instruction(inst) => inst.into_py(py),
+            Self::Gate(gate) => gate.into_py(py),
+            Self::Operation(op) => op.into_py(py),
+        }
+    }
+}
+
 impl Operation for OperationType {
     fn name(&self) -> &str {
         match self {
@@ -1418,6 +1429,16 @@ impl PyInstruction {
             instruction,
         }
     }
+
+    fn __deepcopy__(&self, py: Python, _memo: PyObject) -> PyResult<Self> {
+        Ok(PyInstruction {
+            qubits: self.qubits,
+            clbits: self.clbits,
+            params: self.params,
+            op_name: self.op_name.clone(),
+            instruction: DEEPCOPY.get_bound(py).call1((&self.instruction,))?.unbind(),
+        })
+    }
 }
 
 impl Operation for PyInstruction {
@@ -1497,6 +1518,16 @@ impl PyGate {
             gate,
         }
     }
+
+    fn __deepcopy__(&self, py: Python, _memo: PyObject) -> PyResult<Self> {
+        Ok(PyGate {
+            qubits: self.qubits,
+            clbits: self.clbits,
+            params: self.params,
+            op_name: self.op_name.clone(),
+            gate: DEEPCOPY.get_bound(py).call1((&self.gate,))?.unbind(),
+        })
+    }
 }
 
 impl Operation for PyGate {
@@ -1589,6 +1620,16 @@ impl PyOperation {
             operation,
         }
     }
+
+    fn __deepcopy__(&self, py: Python, _memo: PyObject) -> PyResult<Self> {
+        Ok(PyOperation {
+            qubits: self.qubits,
+            clbits: self.clbits,
+            params: self.params,
+            op_name: self.op_name.clone(),
+            operation: DEEPCOPY.get_bound(py).call1((&self.operation,))?.unbind(),
+        })
+    }
 }
 
 impl Operation for PyOperation {

qiskit/converters/circuit_to_dag.py

@@ -13,7 +13,8 @@
 """Helper function for converting a circuit to a dag"""
 import copy
 
-from qiskit.dagcircuit.dagcircuit import DAGCircuit
+from qiskit.dagcircuit.dagcircuit import DAGCircuit, DAGOpNode
+from qiskit._accelerate.circuit import StandardGate
 
 
 def circuit_to_dag(circuit, copy_operations=True, *, qubit_order=None, clbit_order=None):
@@ -93,10 +94,24 @@ def circuit_to_dag(circuit, copy_operations=True, *, qubit_order=None, clbit_ord
         dagcircuit.add_creg(register)
 
     for instruction in circuit.data:
-        op = instruction.operation
-        if copy_operations:
-            op = copy.deepcopy(op)
-        dagcircuit.apply_operation_back(op, instruction.qubits, instruction.clbits, check=False)
+        if not isinstance(instruction._raw_op, StandardGate):
+            op = instruction.operation
+            if copy_operations:
+                op = copy.deepcopy(op)
+            dagcircuit.apply_operation_back(op, instruction.qubits, instruction.clbits, check=False)
+        else:
+            node = DAGOpNode(
+                instruction._raw_op,
+                qargs=instruction.qubits,
+                cargs=instruction.clbits,
+                params=instruction.params,
+                label=instruction.label,
+                duration=instruction.duration,
+                unit=instruction.unit,
+                condition=instruction.condition,
+                dag=dagcircuit,
+            )
+            dagcircuit._apply_op_node_back(node)
 
     dagcircuit.duration = circuit.duration
     dagcircuit.unit = circuit.unit