🔀 Merge pull request #71 from DVLab-NTU/refactor/tensor-decomp-remove…

…-num-qubit-injection

♻️ remove the need to inject num qubit for tensor decomposer

src/convert/conversion_cmd.cpp

@@ -163,10 +163,7 @@ Command conversion_cmd(QCirMgr& qcir_mgr, qsyn::tensor::TensorMgr& tensor_mgr, q
                     if (!dvlab::utils::mgr_has_data(tensor_mgr)) return CmdExecResult::error;
 
                     spdlog::info("Converting Tensor {} to QCir {}...", tensor_mgr.focused_id(), qcir_mgr.get_next_id());
-                    auto ts           = tensor_mgr.get();
-                    const size_t qreg = size_t(log2((*ts).shape()[0]));
-                    tensor::Decomposer decomp(qreg);
-                    auto result = decomp.decompose(*ts);
+                    auto const result = tensor::Decomposer{}.decompose(*tensor_mgr.get());
 
                     if (result) {
                         qcir_mgr.add(qcir_mgr.get_next_id(), std::make_unique<qcir::QCir>(std::move(*result)));

src/tensor/decomposer.cpp

@@ -0,0 +1,48 @@
+/****************************************************************************
+  PackageName  [ tensor ]
+  Synopsis     [ Define tensor decomposer structure ]
+  Author       [ Design Verification Lab ]
+  Copyright    [ Copyright(c) 2023 DVLab, GIEE, NTU, Taiwan ]
+****************************************************************************/
+
+#include "./decomposer.hpp"
+
+namespace qsyn::tensor {
+
+/**
+ * @brief Append gate and save the encoding gate sequence
+ *
+ * @param target
+ * @param qubit_list
+ * @param gate_list
+ */
+void Decomposer::encode_control_gate(QubitIdList const& target, std::vector<QubitIdList>& qubit_list, std::vector<std::string>& gate_list) {
+    qubit_list.emplace_back(target);
+    gate_list.emplace_back(target.size() == 2 ? "cx" : "x");
+    _quantum_circuit.add_gate(target.size() == 2 ? "cx" : "x", target, {}, true);
+}
+
+/**
+ * @brief Gray encoder
+ *
+ * @param origin_pos Origin qubit
+ * @param targ_pos Target qubit
+ * @param qubit_list
+ * @param gate_list
+ */
+void Decomposer::encode(size_t origin_pos, size_t targ_pos, std::vector<QubitIdList>& qubit_list, std::vector<std::string>& gate_list) {
+    bool x_given = 0;
+    if (((origin_pos >> targ_pos) & 1) == 0) {
+        encode_control_gate({int(targ_pos)}, qubit_list, gate_list);
+        x_given = 1;
+    }
+    for (size_t i = 0; i < _n_qubits; i++) {
+        if (i == targ_pos) continue;
+        if (((origin_pos >> i) & 1) == 0)
+            encode_control_gate({int(targ_pos), int(i)}, qubit_list, gate_list);
+    }
+    if (x_given)
+        encode_control_gate({int(targ_pos)}, qubit_list, gate_list);
+}
+
+}  // namespace qsyn::tensor