Fix README and Circuit::transpile

Author: long-long-float

README.md

@@ -9,6 +9,8 @@ simple-qsim is a simple quantum circuit simulator written in Rust. It simulates
 - Basic gates (X, H, CNOT, etc.)
 - Observable for Pauli operators (I, X, Y, Z)
 - Parametric gates for RX, RY, RZ
+- Transpiler by Solovay-Kitaev algorithm (Thanks to [sk](https://github.com/cmdawson/sk))
+    - Currently, single-qubit gates are supported.
 
 ## Installation
 
@@ -49,6 +51,12 @@ You can run examples by:
 cargo run --example qcl
 ```
 
+## Test
+
+```
+cargo test
+```
+
 ## License
 
 This project is licensed under the MIT License.

src/circuit.rs

@@ -4,8 +4,9 @@ use nalgebra_sparse::{coo::CooMatrix, csr::CsrMatrix};
 use num_complex::Complex;
 
 use crate::gates::{
-    h_matrix, inv_t_matrix, rx_matrix, ry_dence_matrix, ry_matrix, rz_dence_matrix, rz_matrix,
-    s_matrix, t_matrix, x_matrix, y_matrix, z_matrix,
+    h_matrix, inv_t_matrix, rx_dence_matrix, rx_matrix, ry_dence_matrix, ry_matrix,
+    rz_dence_matrix, rz_matrix, s_dence_matrix, s_matrix, t_matrix, x_dence_matrix, x_matrix,
+    y_dence_matrix, y_matrix, z_dence_matrix, z_matrix,
 };
 use crate::net::{Knot, Net};
 use crate::qstate::QState;
@@ -306,7 +307,18 @@ impl Circuit {
         let mut new_gates = Vec::new();
 
         for gate in &self.gates {
+            if !matches!(gate.index, GateIndex::One(_)) {
+                return Err(anyhow::anyhow!(
+                    "Only single qubit gates are supported for transpilation"
+                ));
+            }
+
             let u = match &gate.kind {
+                GateKind::S => s_dence_matrix(),
+                GateKind::X => x_dence_matrix(),
+                GateKind::Y => y_dence_matrix(),
+                GateKind::Z => z_dence_matrix(),
+                GateKind::RX(angle) => rx_dence_matrix(*angle),
                 GateKind::RY(angle) => ry_dence_matrix(*angle),
                 GateKind::RZ(angle) => rz_dence_matrix(*angle),
                 _ => {

src/gates.rs

@@ -122,6 +122,15 @@ pub fn s_matrix() -> CsrMatrix<Qbit> {
     CsrMatrix::from(&s_coo)
 }
 
+pub fn s_dence_matrix() -> Matrix2<Qbit> {
+    Matrix2::from_column_slice(&[
+        Complex::ONE,
+        Complex::ZERO,
+        Complex::ZERO,
+        Complex::new(0.0, 1.0),
+    ])
+}
+
 pub fn t_matrix() -> CsrMatrix<Qbit> {
     let mut t_coo = CooMatrix::new(2, 2);
     t_coo.push(0, 0, Complex::new(1.0, 0.0));