PennyLane QASM 使用示例

In [1]:

import pennylane as qml
print(qml.__version__)
# 预期输出：0.3x.x 或更高

import pennylane as qml print(qml.__version__) # 预期输出：0.3x.x 或更高

0.43.2

In [2]:

import pennylane as qml
from pennylane import numpy as np
import sys

# 1. 环境审计
print(f"System Version: {sys.version}")
print(f"PennyLane Version: {qml.__version__}")

# 确保版本匹配，防止 API 变动导致的误判
if "0.43" not in qml.__version__:
    print("⚠️ Warning: This audit script is optimized for PennyLane 0.43.x")

class PennyLaneAuditor:
    """
    PennyLane OpenQASM 导出能力审计器 (针对 v0.43.2 API)。
    """
    
    @staticmethod
    def inspect_export(qnode, args=(), kwargs={}, description=""):
        """
        审计 QNode 的 OpenQASM 导出行为。
        
        Args:
            qnode (QNode): 定义好的 PennyLane QNode。
            args (tuple): 传递给 QNode 的位置参数。
            kwargs (dict): 传递给 QNode 的关键字参数。
        """
        print(f"\n{'='*10} [Audit: {description}] {'='*10}")
        
        try:
            # API 引用: pennylane.to_openqasm(qnode, wires=None, measure_all=True)
            # PennyLane 的导出是基于"变换(Transform)"的。
            # qml.to_openqasm(qnode) 返回一个新的函数，该函数在被调用时返回 QASM 字符串。
            
            qasm_fn = qml.to_openqasm(qnode, measure_all=False)
            qasm_str = qasm_fn(*args, **kwargs)
            
            # 打印前 10 行以供检查
            print(">>> Export Snippet:")
            print('\n'.join(qasm_str.splitlines()[:15]))
            if len(qasm_str.splitlines()) > 15:
                print("... (truncated)")

            # 核心特征审计
            analysis = []
            
            # 1. 版本检查
            if "OPENQASM 2.0" in qasm_str:
                analysis.append("Format: OpenQASM 2.0 (Legacy)")
            elif "OPENQASM 3" in qasm_str:
                analysis.append("Format: OpenQASM 3.0 (Modern)")
            else:
                analysis.append("Format: Unknown")

            # 2. 参数绑定检查
            # 检查具体的数值是否出现在代码中 (硬编码)
            is_hardcoded = False
            for arg in args:
                if isinstance(arg, (int, float, np.ndarray)):
                    # 简单的启发式检查：看参数的字符串形式是否出现在 QASM 中
                    val_str = str(np.round(arg, 4)) if isinstance(arg, float) else str(arg)
                    # 去除 rx(0.5) 这种可能匹配的情况
                    if val_str in qasm_str:
                        is_hardcoded = True
                        break
            
            if is_hardcoded:
                analysis.append("Parameters: Hardcoded (Bound)")
            elif "input " in qasm_str:
                analysis.append("Parameters: Runtime Input (Unbound)")
            
            # 3. 控制流检查
            if "if (" in qasm_str and "c_if" not in qasm_str: # QASM 2 的 if 是 c_if 语法糖
                 analysis.append("Logic: Native 'if' (QASM 3)")
            elif "if(" in qasm_str or "if " in qasm_str:
                 analysis.append("Logic: Legacy 'if' (QASM 2 style)")
            else:
                 analysis.append("Logic: Linearized (No control flow)")

            print(f"\n[Analysis Result] -> {', '.join(analysis)}")
            
        except Exception as e:
            print(f"[Analysis] ❌ Export Failed: {e}")

print("Auditor Ready.")

import pennylane as qml from pennylane import numpy as np import sys # 1. 环境审计 print(f"System Version: {sys.version}") print(f"PennyLane Version: {qml.__version__}") # 确保版本匹配，防止 API 变动导致的误判 if "0.43" not in qml.__version__: print("⚠️ Warning: This audit script is optimized for PennyLane 0.43.x") class PennyLaneAuditor: """ PennyLane OpenQASM 导出能力审计器 (针对 v0.43.2 API)。 """ @staticmethod def inspect_export(qnode, args=(), kwargs={}, description=""): """ 审计 QNode 的 OpenQASM 导出行为。 Args: qnode (QNode): 定义好的 PennyLane QNode。 args (tuple): 传递给 QNode 的位置参数。 kwargs (dict): 传递给 QNode 的关键字参数。 """ print(f"\n{'='*10} [Audit: {description}] {'='*10}") try: # API 引用: pennylane.to_openqasm(qnode, wires=None, measure_all=True) # PennyLane 的导出是基于"变换(Transform)"的。 # qml.to_openqasm(qnode) 返回一个新的函数，该函数在被调用时返回 QASM 字符串。 qasm_fn = qml.to_openqasm(qnode, measure_all=False) qasm_str = qasm_fn(*args, **kwargs) # 打印前 10 行以供检查 print(">>> Export Snippet:") print('\n'.join(qasm_str.splitlines()[:15])) if len(qasm_str.splitlines()) > 15: print("... (truncated)") # 核心特征审计 analysis = [] # 1. 版本检查 if "OPENQASM 2.0" in qasm_str: analysis.append("Format: OpenQASM 2.0 (Legacy)") elif "OPENQASM 3" in qasm_str: analysis.append("Format: OpenQASM 3.0 (Modern)") else: analysis.append("Format: Unknown") # 2. 参数绑定检查 # 检查具体的数值是否出现在代码中 (硬编码) is_hardcoded = False for arg in args: if isinstance(arg, (int, float, np.ndarray)): # 简单的启发式检查：看参数的字符串形式是否出现在 QASM 中 val_str = str(np.round(arg, 4)) if isinstance(arg, float) else str(arg) # 去除 rx(0.5) 这种可能匹配的情况 if val_str in qasm_str: is_hardcoded = True break if is_hardcoded: analysis.append("Parameters: Hardcoded (Bound)") elif "input " in qasm_str: analysis.append("Parameters: Runtime Input (Unbound)") # 3. 控制流检查 if "if (" in qasm_str and "c_if" not in qasm_str: # QASM 2 的 if 是 c_if 语法糖 analysis.append("Logic: Native 'if' (QASM 3)") elif "if(" in qasm_str or "if " in qasm_str: analysis.append("Logic: Legacy 'if' (QASM 2 style)") else: analysis.append("Logic: Linearized (No control flow)") print(f"\n[Analysis Result] -> {', '.join(analysis)}") except Exception as e: print(f"[Analysis] ❌ Export Failed: {e}") print("Auditor Ready.")

System Version: 3.12.12 | packaged by Anaconda, Inc. | (main, Oct 21 2025, 20:05:38) [MSC v.1929 64 bit (AMD64)]
PennyLane Version: 0.43.2
Auditor Ready.

In [3]:

# 定义设备
dev = qml.device("default.qubit", wires=2)

@qml.qnode(dev)
def circuit_param(x, y):
    # 在 PennyLane 中，x 和 y 通常是具体的数值张量，而不是符号
    qml.RX(x, wires=0)
    qml.RY(y, wires=1)
    qml.CNOT(wires=[0, 1])
    return qml.expval(qml.Z(0))

def test_parameters():
    # 传入具体数值
    params = (0.543, 1.234)
    PennyLaneAuditor.inspect_export(
        circuit_param, 
        args=params, 
        description="Parameterized Circuit (Expect Hardcoding)"
    )

test_parameters()

# 定义设备 dev = qml.device("default.qubit", wires=2) @qml.qnode(dev) def circuit_param(x, y): # 在 PennyLane 中，x 和 y 通常是具体的数值张量，而不是符号 qml.RX(x, wires=0) qml.RY(y, wires=1) qml.CNOT(wires=[0, 1]) return qml.expval(qml.Z(0)) def test_parameters(): # 传入具体数值 params = (0.543, 1.234) PennyLaneAuditor.inspect_export( circuit_param, args=params, description="Parameterized Circuit (Expect Hardcoding)" ) test_parameters()

========== [Audit: Parameterized Circuit (Expect Hardcoding)] ==========
>>> Export Snippet:
OPENQASM 2.0;
include "qelib1.inc";
qreg q[2];
creg c[2];
rx(0.543) q[0];
ry(1.234) q[1];
cx q[0],q[1];
measure q[0] -> c[0];

[Analysis Result] -> Format: OpenQASM 2.0 (Legacy), Parameters: Hardcoded (Bound), Logic: Linearized (No control flow)

In [4]:

@qml.qnode(dev)
def circuit_cond(measure_val):
    qml.Hadamard(wires=0)
    
    # 定义受控逻辑: 如果 measure_val > 0 (即为 1)，则执行 X
    # 注意：PennyLane 0.43 支持将测量值传递给 qml.cond
    m = qml.measure(0)
    
    def true_branch():
        qml.X(1)

    # 这里的条件是基于“中途测量结果 m”
    qml.cond(m == 1, true_branch)()
    
    return qml.probs(wires=1)

def test_conditional():
    # 这里的参数其实不影响电路结构，因为条件是内部测量产生的
    PennyLaneAuditor.inspect_export(
        circuit_cond, 
        args=(0,), 
        description="Conditional Logic (qml.cond)"
    )

test_conditional()

@qml.qnode(dev) def circuit_cond(measure_val): qml.Hadamard(wires=0) # 定义受控逻辑: 如果 measure_val > 0 (即为 1)，则执行 X # 注意：PennyLane 0.43 支持将测量值传递给 qml.cond m = qml.measure(0) def true_branch(): qml.X(1) # 这里的条件是基于“中途测量结果 m” qml.cond(m == 1, true_branch)() return qml.probs(wires=1) def test_conditional(): # 这里的参数其实不影响电路结构，因为条件是内部测量产生的 PennyLaneAuditor.inspect_export( circuit_cond, args=(0,), description="Conditional Logic (qml.cond)" ) test_conditional()

========== [Audit: Conditional Logic (qml.cond)] ==========
[Analysis] ❌ Export Failed: to_openqasm does not support translating Conditionals with measurement postprocessing.

PennyLane 的原生 to_openqasm 功能极弱，不可用于导出含控制流的电路。它仅适用于简单的、线性的量子门序列导出。一旦涉及到基于测量的反馈（Feedback）或条件执行，导出器就会因无法处理中间测量值的逻辑映射而崩溃。