[Refactor] Rename "DAG" to "CircuitSeq" (#61)

* [Refactor] Rename "DAG" to "CircuitSeq"

* fix compilation error

CODE_STRUCTURE.md

@@ -21,44 +21,44 @@ In `src/quartz/context/rule_parser.h`
 * `class RuleParser`: define the rules to write 3-qubit gates in each of the gate sets
 
 In `src/quartz/parser/qasm_parser.h`
-* `class QASMParser`: parse an input QASM file to Quartz's DAG representation
+* `class QASMParser`: parse an input QASM file to Quartz's CircuitSeq representation
 
-In `src/dag/dag.h`
-* `class DAG`: a circuit represented in a DAG with all gates stored in an `std::vector` (which is a sequence representation)
+In `src/quartz/circuitseq/circuitseq.h`
+* `class CircuitSeq`: a circuit sequence with all gates stored in an `std::vector`
 
-In `src/dag/dagnode.h`
-* `class DAGNode`: a node in DAG corresponds to a wire in the circuit
+In `src/quartz/circuitseq/circuitwire.h`
+* `class CircuitWire`: a wire in the circuit sequence
 
-In `src/dag/daghyperedge.h`
-* `class DAGHyperEdge`: a hyperedge in DAG corresponds to a gate (or parameter expression) in the circuit
+In `src/quartz/circuitseq/circuitgate.h`
+* `class CircuitGate`: a gate (or parameter expression) in the circuit sequence
 
-In `src/dataset/dataset.h`
+In `src/quartz/dataset/dataset.h`
 * `class Dataset`: a collection of circuits grouped by fingerprints
 
-In `src/dataset/equivalence_set.h`
+In `src/quartz/dataset/equivalence_set.h`
 * `class EquivalenceClass`: an ECC
 * `class EquivalenceSet`: an ECC set
 
-In `src/generator/generator.h`
+In `src/quartz/generator/generator.h`
 * `class Generator`: the circuit generator
 * `Generator::generate`: generate circuits for an unverified ECC set (then use `src/python/verify_equivalences.py` to get the ECC set)
 
-In `src/math/matrix.h`
+In `src/quartz/math/matrix.h`
 * `class Matrix`: a complex square matrix
 
-In `src/math/vector.h`
+In `src/quartz/math/vector.h`
 * `class Vector`: a complex vector
 
-In `src/verifier/verifier.h`
+In `src/quartz/verifier/verifier.h`
 * `Verifier::redundant`: check if the circuit generated is redundant, i.e., having some slices not in the representative set
 
-In `src/tasograph/tasograph.h`
+In `src/quartz/tasograph/tasograph.h`
 * `class Graph`: the circuit to be optimized
 * `Graph::optimize`: use the search algorithm to optimize the circuit
 * `Graph::context_shift`: shift the context of the circuit, e.g., changing the gate set
 
-In `src/tasograph/substitution.h`
+In `src/quartz/tasograph/substitution.h`
 * `class GraphXfer`: a circuit transformation
 
-In `src/test/gen_ecc_set.cpp`
+In `src/quartz/test/gen_ecc_set.cpp`
 * `gen_ecc_set`: a function to generate ECC sets with given gate set and hyperparameters

README.md

@@ -70,26 +70,26 @@ After that, you need a `QASMParser` object to parse the input `qasm` file. You c
 QASMParser qasm_parser(&src_ctx);
 ```
 
-Now you can use the `QASMParser` object to load the circuit from the `qasm` file to a `DAG` object, as below:
+Now you can use the `QASMParser` object to load the circuit from the `qasm` file to a `CircuitSeq` object, as below:
 
 ``` cpp
-DAG *dag = nullptr;
-if (!qasm_parser.load_qasm(input_fn, dag)) {
+CircuitSeq *seq = nullptr;
+if (!qasm_parser.load_qasm(input_fn, seq)) {
     std::cout << "Parser failed" << std::endl;
 }
 ```
 
-After you have the circuit loaded into the `DAG` object, you can construct a `Graph` object from it. The `Graph` object is the final circuit representation used in our optimizer. You can construct it as below:
+After you have the circuit loaded into the `CircuitSeq` object, you can construct a `Graph` object from it. The `Graph` object is the final circuit representation used in our optimizer. You can construct it as below:
 
 ``` cpp
-Graph graph(&src_ctx, dag);
+Graph graph(&src_ctx, seq);
 ```
 
 #### Context shift
 
 If the input gate set is different from your target gate set, you should consider using the `context_shift` APIs to shift the context constructed with the gate sets to a context constructed with the target gate set.
 
-To shift the context, you should create three `Contxt` objects, one for input, one for target, and one for their union as below:
+To shift the context, you should create three `Context` objects, one for input, one for target, and one for their union as below:
 
 ``` cpp
 Context src_ctx({GateType::h, GateType::ccz, GateType::x, GateType::cx,

python/quartz/_cython/CCore.pxd

@@ -69,22 +69,22 @@ cdef extern from "context/context.h" namespace "quartz":
 
 ctypedef Context* Context_ptr
 
-cdef extern from "dag/dag.h" namespace "quartz":
-    cdef cppclass DAG:
-        DAG(int, int) except +
+cdef extern from "circuitseq/circuitseq.h" namespace "quartz":
+    cdef cppclass CircuitSeq:
+        CircuitSeq(int, int) except +
         int get_num_qubits() const
         int get_num_input_parameters() const
         int get_num_total_parameters() const
         int get_num_internal_parameters() const
         int get_num_gates() const
 
-ctypedef DAG* DAG_ptr
+ctypedef CircuitSeq* CircuitSeq_ptr
 
 cdef extern from "tasograph/substitution.h" namespace "quartz":
     cdef cppclass GraphXfer:
-        GraphXfer(Context_ptr, const DAG_ptr, const DAG_ptr) except +
+        GraphXfer(Context_ptr, const CircuitSeq_ptr, const CircuitSeq_ptr) except +
         @staticmethod
-        GraphXfer* create_GraphXfer(Context_ptr,const DAG_ptr ,const DAG_ptr, bool no_increase)
+        GraphXfer* create_GraphXfer(Context_ptr,const CircuitSeq_ptr ,const CircuitSeq_ptr, bool no_increase)
         int num_src_op()
         int num_dst_op()
         string src_str()
@@ -106,7 +106,7 @@ cdef extern from "tasograph/tasograph.h" namespace "quartz":
 cdef extern from "tasograph/tasograph.h" namespace "quartz":
     cdef cppclass Graph:
         Graph(Context *) except +
-        Graph(Context *, const DAG *) except +
+        Graph(Context *, const CircuitSeq *) except +
         bool xfer_appliable(GraphXfer *, Op) except +
         shared_ptr[Graph] apply_xfer(GraphXfer *, Op, bool) except +
         pair[shared_ptr[Graph], vector[int]] apply_xfer_and_track_node(GraphXfer *, Op, bool) except +
@@ -137,11 +137,11 @@ cdef extern from "dataset/equivalence_set.h" namespace "quartz":
         EquivalenceSet() except +
         int num_equivalence_classes() const
         bool load_json(Context *, const string)
-        vector[vector[DAG_ptr]] get_all_equivalence_sets() except +
+        vector[vector[CircuitSeq_ptr]] get_all_equivalence_sets() except +
 
 
 cdef extern from "parser/qasm_parser.h" namespace "quartz":
     cdef cppclass QASMParser:
         QASMParser(Context *)
-        bool load_qasm(const string &, DAG *&) except +
-        bool load_qasm_str(const string &, DAG *&) except +
+        bool load_qasm(const string &, CircuitSeq *&) except +
+        bool load_qasm_str(const string &, CircuitSeq *&) except +

python/quartz/_cython/core.pyx

@@ -1,9 +1,9 @@
 # distutils: language = c++
 
 from CCore cimport (
-    DAG,
+    CircuitSeq,
+    CircuitSeq_ptr,
     Context,
-    DAG_ptr,
     Edge,
     EquivalenceSet,
     Gate,
@@ -147,18 +147,18 @@ cdef class PyGate:
 
 
 cdef class PyDAG:
-    cdef DAG_ptr dag
+    cdef CircuitSeq_ptr dag
 
     def __cinit__(self, *, int num_qubits=-1, int num_input_params=-1):
         if num_qubits >= 0 and num_input_params >= 0:
-            self.dag = new DAG(num_qubits, num_input_params)
+            self.dag = new CircuitSeq(num_qubits, num_input_params)
         else:
             self.dag = NULL
 
     def __dealloc__(self):
         pass
 
-    cdef set_this(self, DAG_ptr dag_):
+    cdef set_this(self, CircuitSeq_ptr dag_):
         self.dag = dag_
         return self
 

src/benchmark/nam_middle_circuits.cpp

@@ -27,7 +27,7 @@ void benchmark_nam(const std::string &circuit_name) {
   auto xfer_pair = GraphXfer::ccz_cx_rz_xfer(&union_ctx);
   // Load qasm file
   QASMParser qasm_parser(&src_ctx);
-  DAG *dag = nullptr;
+  CircuitSeq *dag = nullptr;
   if (!qasm_parser.load_qasm(circuit_path, dag)) {
     std::cout << "Parser failed" << std::endl;
     return;

src/benchmark/nam_small_circuits.cpp

@@ -27,7 +27,7 @@ void benchmark_nam(const std::string &circuit_name) {
   auto xfer_pair = GraphXfer::ccz_cx_rz_xfer(&union_ctx);
   // Load qasm file
   QASMParser qasm_parser(&src_ctx);
-  DAG *dag = nullptr;
+  CircuitSeq *dag = nullptr;
   if (!qasm_parser.load_qasm(circuit_path, dag)) {
     std::cout << "Parser failed" << std::endl;
     return;

src/python/verifier/verifier.py

@@ -214,7 +214,7 @@ def phase_shift(vec, lam):
 
 
 def phase_shift_by_id(vec, dag, phase_shift_id, all_parameters):
-    # Warning: If DAG::hash() is modified, this function should be modified correspondingly.
+    # Warning: If CircuitSeq::hash() is modified, this function should be modified correspondingly.
     dag_meta = dag[0]
     num_total_params = dag_meta[meta_index_num_total_parameters]
     if (
@@ -680,13 +680,13 @@ def find_equivalences(
         num_hashtags = len(data)
         num_dags = sum(len(dags) for dags in data.values())
         num_potential_equivalences = num_dags - num_hashtags
-        # first process hashtags with only 1 DAG
+        # first process hashtags with only 1 CircuitSeq
         for hashtag, dags in data.items():
             if len(dags) == 1:
                 output_dict[hashtag + "_0"] = [dags[0]]
                 num_different_dags_with_same_hash[hashtag] = 1
         print(
-            f"Processed {len(output_dict)} hash values that had only 1 DAG, now processing the remaining {len(data) - len(output_dict)} ones with 2 or more DAGs..."
+            f"Processed {len(output_dict)} hash values that had only 1 circuit sequence, now processing the remaining {len(data) - len(output_dict)} ones with 2 or more circuit sequences..."
         )
         # now process hashtags with >1 DAGs
         with mp.Pool() as pool:
@@ -727,10 +727,10 @@ def find_equivalences(
 
             # A map from other hashtags to corresponding phase shifts.
             other_hashtags = defaultdict(dict)
-            # |other_hashtags[other_hash][None]| indicates that if it's possible that a DAG with |other_hash|
-            #    is equivalent with a DAG with |hashtag| without phase shifts.
+            # |other_hashtags[other_hash][None]| indicates that if it's possible that a CircuitSeq with |other_hash|
+            #    is equivalent with a CircuitSeq with |hashtag| without phase shifts.
             # |other_hashtags[other_hash][phase_shift_id]| is a list of DAGs with |hashtag| that can be equivalent
-            #    to a DAG with |other_hash| under phase shift |phase_shift_id|.
+            #    to a CircuitSeq with |other_hash| under phase shift |phase_shift_id|.
             assert len(dags) > 0
             for dag in dags:
                 dag_meta = dag[0]
@@ -742,7 +742,7 @@ def find_equivalences(
                         # phase shift id is item[1]
                         assert isinstance(item, list)
                         assert len(item) == 2
-                        # We need the exact parameter in |dag|, so we cannot use the representative DAG |dags[0]|.
+                        # We need the exact parameter in |dag|, so we cannot use the representative CircuitSeq |dags[0]|.
                         other_hashtags[item[0]][item[1]] = other_hashtags[item[0]].get(
                             item[1], []
                         ) + [dag]
@@ -798,7 +798,7 @@ def find_equivalences(
                         # Pruning: we only need to try each input parameter once.
                         input_param_tried = False
                         for dag in dag_list:
-                            # Warning: If DAG::hash() is modified,
+                            # Warning: If CircuitSeq::hash() is modified,
                             # the expression |is_fixed_for_all_dags| should be modified correspondingly.
                             is_fixed_for_all_dags = (
                                 0
@@ -819,7 +819,7 @@ def find_equivalences(
                                     input_param_tried = True
                             equivalent_called_2 += 1
                             possible_num_equivalences_under_phase_shift += 1
-                            # |phase_shift_id[0]| is the DAG generating this phase shift id.
+                            # |phase_shift_id[0]| is the CircuitSeq generating this phase shift id.
                             if equivalent(
                                 dag,
                                 other_dag,

src/quartz/dag/daghyperedge.cpp → src/quartz/circuitseq/circuitgate.cpp

@@ -1,10 +1,10 @@
-#include "daghyperedge.h"
-#include "dagnode.h"
+#include "circuitgate.h"
+#include "circuitwire.h"
 
 namespace quartz {
-int DAGHyperEdge::get_min_qubit_index() const {
+int CircuitGate::get_min_qubit_index() const {
   int result = -1;
-  for (auto &input_node : input_nodes) {
+  for (auto &input_node : input_wires) {
     if (input_node->is_qubit() &&
         (result == -1 || input_node->index < result)) {
       result = input_node->index;

src/quartz/circuitseq/circuitgate.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "../gate/gate.h"
+#include "../utils/utils.h"
+
+#include <vector>
+
+namespace quartz {
+
+class CircuitWire;
+
+/**
+ * A gate in the circuit.
+ * Stores the gate type, input and output information.
+ */
+class CircuitGate {
+public:
+  int get_min_qubit_index() const;
+  std::vector<CircuitWire *> input_wires; // Include parameters!
+  std::vector<CircuitWire *> output_wires;
+
+  Gate *gate;
+};
+} // namespace quartz