Add DAGDependency

qiskit/converters/__init__.py

@@ -27,13 +27,21 @@
    circuit_to_instruction
    circuit_to_gate
    ast_to_dag
+   dagdependency_to_circuit
+   circuit_to_dagdependency
+   dag_to_dagdependency
+   dagdependency_to_dag
 """
 
 from .circuit_to_dag import circuit_to_dag
 from .dag_to_circuit import dag_to_circuit
 from .circuit_to_instruction import circuit_to_instruction
 from .circuit_to_gate import circuit_to_gate
 from .ast_to_dag import ast_to_dag
+from .circuit_to_dagdependency import circuit_to_dagdependency
+from .dagdependency_to_circuit import dagdependency_to_circuit
+from .dag_to_dagdependency import dag_to_dagdependency
+from .dagdependency_to_dag import dagdependency_to_dag
 
 
 def isinstanceint(obj):

qiskit/converters/circuit_to_dagdependency.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+'''Helper function for converting a circuit to a dag dependency'''
+
+from qiskit.dagcircuit.dagdependency import DAGDependency
+
+
+def circuit_to_dagdependency(circuit):
+    """Build a ``DAGDependency`` object from a ``QuantumCircuit``.
+
+    Args:
+        circuit (QuantumCircuit): the input circuits.
+
+    Return:
+        DAGDependency: the DAG representing the input circuit as a dag dependency.
+    """
+    dagdependency = DAGDependency()
+    dagdependency.name = circuit.name
+
+    for register in circuit.qregs:
+        dagdependency.add_qreg(register)
+
+    for register in circuit.cregs:
+        dagdependency.add_creg(register)
+
+    for operation, qargs, cargs in circuit.data:
+        dagdependency.add_op_node(operation, qargs, cargs)
+        dagdependency.add_edge()
+
+    dagdependency.add_successors()
+
+    return dagdependency

qiskit/converters/dag_to_dagdependency.py

@@ -0,0 +1,50 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Helper function for converting a dag circuit to a dag dependency"""
+from qiskit.dagcircuit.dagdependency import DAGDependency
+
+
+def dag_to_dagdependency(dag):
+    """Build a ``DAGDependency`` object from a ``DAGCircuit``.
+
+    Args:
+        dag (DAGCircuit): the input dag.
+
+    Return:
+        DAGDependency: the DAG representing the input circuit as a dag dependency.
+    """
+
+    dagdependency = DAGDependency()
+    DAGDependency.name = dag.name
+
+    qregs = list(dag.qregs.values())
+    cregs = list(dag.cregs.values())
+
+    for register in qregs:
+        dagdependency.add_qreg(register)
+
+    for register in cregs:
+        dagdependency.add_creg(register)
+
+    for node in dag.topological_op_nodes():
+        # Get arguments for classical control (if any)
+        inst = node.op.copy()
+        inst.condition = node.condition
+        dagdependency.add_op_node(inst, node.qargs, node.cargs)
+        dagdependency.add_edge()
+
+    dagdependency.add_successors()
+
+    return dagdependency

qiskit/converters/dagdependency_to_circuit.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Helper function for converting a dag dependency to a circuit"""
+from qiskit.circuit import QuantumCircuit
+
+
+def dagdependency_to_circuit(dagdependency):
+    """Build a ``QuantumCircuit`` object from a ``DAGDependency``.
+
+    Args:
+        dagdependency (DAGDependency): the input dag.
+
+    Return:
+        QuantumCircuit: the circuit representing the input dag dependency.
+    """
+
+    name = dagdependency.name or None
+    circuit = QuantumCircuit(*dagdependency.qregs.values(), *dagdependency.cregs.values(),
+                             name=name)
+
+    for node in dagdependency.get_nodes():
+        node_op = node['operation']
+        # Get arguments for classical control (if any)
+        inst = node_op.op.copy()
+        inst.condition = node_op.condition
+        circuit._append(inst, node_op.qargs, node_op.cargs)
+
+    return circuit

qiskit/converters/dagdependency_to_dag.py

@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Helper function for converting a dag dependency to a dag circuit"""
+from qiskit.dagcircuit.dagcircuit import DAGCircuit
+
+
+def dagdependency_to_dag(dagdependency):
+    """Build a ``DAGCircuit`` object from a ``DAGDependency``.
+
+    Args:
+        dag dependency (DAGDependency): the input dag.
+
+    Return:
+        DAGCircuit: the DAG representing the input circuit.
+    """
+
+    dagcircuit = DAGCircuit()
+    dagcircuit.name = dagdependency.name
+
+    qregs = list(dagdependency.qregs.values())
+    cregs = list(dagdependency.cregs.values())
+
+    for register in qregs:
+        dagcircuit.add_qreg(register)
+
+    for register in cregs:
+        dagcircuit.add_creg(register)
+
+    for node in dagdependency.get_nodes():
+        node_op = node['operation']
+        # Get arguments for classical control (if any)
+        inst = node_op.op.copy()
+        inst.condition = node_op.condition
+
+        dagcircuit.apply_operation_back(inst, node_op.qargs, node_op.cargs, inst.condition)
+
+    return dagcircuit

qiskit/dagcircuit/__init__.py

@@ -27,6 +27,7 @@
 
    DAGCircuit
    DAGNode
+   DAGDependency
 
 Exceptions
 ==========
@@ -39,3 +40,4 @@
 from .dagcircuit import DAGCircuit
 from .dagnode import DAGNode
 from .exceptions import DAGCircuitError
+from .dagdependency import DAGDependency