[WIP] Make RVGate a standard gate

crates/circuit/src/gate_matrix.rs

@@ -516,3 +516,19 @@ pub fn xx_plus_yy_gate(theta: f64, beta: f64) -> GateArray2Q {
         [C_ZERO, C_ZERO, C_ZERO, C_ONE],
     ]
 }
+
+pub fn rv_gate(v_x: f64, v_y: f64, v_z: f64) -> GateArray1Q {
+    let angle = ((v_x * v_x) + (v_y * v_y) + (v_z * v_z)).sqrt();
+    if angle == 0. {
+        return ONE_QUBIT_IDENTITY;
+    }
+    let n_x = v_x / angle;
+    let n_y = v_y / angle;
+    let n_z = v_z / angle;
+    let sin = (angle / 2.).sin();
+    let cos = (angle / 2.).cos();
+    [
+        [cos - IM * n_z * sin, (-n_y - IM * n_x) * sin],
+        [(n_y - IM * n_x) * sin, cos + IM * n_z * sin],
+    ]
+}

crates/circuit/src/imports.rs

@@ -265,6 +265,8 @@ static STDGATE_IMPORT_PATHS: [[&str; 2]; STANDARD_GATE_SIZE] = [
     ["qiskit.circuit.library.standard_gates.x", "C3SXGate"],
     // RC3XGate = 51
     ["qiskit.circuit.library.standard_gates.x", "RC3XGate"],
+    // RVGate = 52
+    ["qiskit.circuit.library.standard_gates.rv", "RVGate"],
 ];
 
 /// A mapping from the enum variant in crate::operations::StandardGate to the python object for the
@@ -326,6 +328,7 @@ static STDGATE_PYTHON_GATES: [PyOnceLock<Py<PyAny>>; STANDARD_GATE_SIZE] = [
     PyOnceLock::new(),
     PyOnceLock::new(),
     PyOnceLock::new(),
+    PyOnceLock::new(),
 ];
 
 #[inline]

crates/circuit/src/operations.rs

@@ -26,7 +26,7 @@ use crate::{Qubit, gate_matrix, impl_intopyobject_for_copy_pyclass};
 
 use nalgebra::{Matrix2, Matrix4};
 use ndarray::{Array2, ArrayView2, Dim, ShapeBuilder, array, aview2};
-use num_complex::Complex64;
+use num_complex::{Complex64, ComplexFloat};
 use smallvec::{SmallVec, smallvec};
 
 use numpy::IntoPyArray;
@@ -636,6 +636,7 @@ pub enum StandardGate {
     C3X = 49,
     C3SX = 50,
     RC3X = 51,
+    RV = 52,
     // Remember to update StandardGate::is_valid_bit_pattern below
     // if you add or remove this enum's variants!
 }
@@ -656,7 +657,7 @@ static STANDARD_GATE_NUM_QUBITS: [u32; STANDARD_GATE_SIZE] = [
     1, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 20-29
     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 30-39
     2, 2, 2, 2, 2, 3, 3, 3, 3, 4, // 40-49
-    4, 4, // 50-51
+    4, 4, 1, // 50-52
 ];
 
 static STANDARD_GATE_NUM_PARAMS: [u32; STANDARD_GATE_SIZE] = [
@@ -665,7 +666,7 @@ static STANDARD_GATE_NUM_PARAMS: [u32; STANDARD_GATE_SIZE] = [
     3, 0, 0, 0, 0, 0, 0, 0, 0, 1, // 20-29
     1, 1, 1, 0, 0, 0, 4, 1, 3, 1, // 30-39
     1, 1, 1, 2, 2, 0, 0, 0, 0, 0, // 40-49
-    0, 0, // 50-51
+    0, 0, 3, // 50-52
 ];
 
 static STANDARD_GATE_NUM_CTRL_QUBITS: [u32; STANDARD_GATE_SIZE] = [
@@ -674,7 +675,7 @@ static STANDARD_GATE_NUM_CTRL_QUBITS: [u32; STANDARD_GATE_SIZE] = [
     0, 1, 1, 1, 1, 0, 0, 0, 0, 1, // 20-29
     1, 1, 1, 1, 1, 1, 1, 1, 1, 0, // 30-39
     0, 0, 0, 0, 0, 2, 2, 1, 0, 3, // 40-49
-    3, 0, // 50-51
+    3, 0, 0, // 50-52
 ];
 
 static STANDARD_GATE_NAME: [&str; STANDARD_GATE_SIZE] = [
@@ -730,6 +731,7 @@ static STANDARD_GATE_NAME: [&str; STANDARD_GATE_SIZE] = [
     "mcx",          // 49 ("c3x")
     "c3sx",         // 50
     "rcccx",        // 51 ("rc3x")
+    "rv",           // 52
 ];
 
 /// Get a slice of all standard gate names.
@@ -862,6 +864,14 @@ impl StandardGate {
             Self::C3X => Some((Self::C3X, smallvec![])),
             Self::C3SX => None, // the inverse in not a StandardGate
             Self::RC3X => None, // the inverse in not a StandardGate
+            Self::RV => Some((
+                Self::RV,
+                smallvec![
+                    multiply_param(&params[0], -1.0),
+                    multiply_param(&params[1], -1.0),
+                    multiply_param(&params[2], -1.0)
+                ],
+            )),
         }
     }
 }
@@ -946,7 +956,7 @@ impl StandardGate {
 //
 // Remove this when std::mem::variant_count() is stabilized (see
 // https://github.com/rust-lang/rust/issues/73662 )
-pub const STANDARD_GATE_SIZE: usize = 52;
+pub const STANDARD_GATE_SIZE: usize = 53;
 
 impl Operation for StandardGate {
     fn name(&self) -> &str {
@@ -1204,6 +1214,12 @@ impl Operation for StandardGate {
                 [] => Some(aview2(&gate_matrix::RC3X_GATE).to_owned()),
                 _ => None,
             },
+            Self::RV => match params {
+                [Param::Float(v_x), Param::Float(v_y), Param::Float(v_z)] => {
+                    Some(aview2(&gate_matrix::rv_gate(*v_x, *v_y, *v_z)).to_owned())
+                }
+                _ => None,
+            },
         }
     }
 
@@ -2241,6 +2257,28 @@ impl Operation for StandardGate {
                 )
                 .expect("Unexpected Qiskit python bug"),
             ),
+            Self::RV => {
+                let mat = self.matrix_as_static_1q(params).unwrap();
+                let det_arg = (mat[0][0] * mat[1][1] - mat[0][1] * mat[1][0]).arg();
+                let theta = 2. * mat[1][0].abs().atan2(mat[0][0].abs());
+                let ang1 = mat[1][1].arg();
+                let ang2 = mat[1][0].arg();
+                let phi = ang1 + ang2 - det_arg;
+                let lam = ang1 - ang2;
+                let phase = (0.5 * det_arg) - 0.5 * (phi + lam);
+                Some(
+                    CircuitData::from_standard_gates(
+                        1,
+                        [(
+                            Self::U,
+                            smallvec![Param::Float(theta), Param::Float(phi), Param::Float(lam)],
+                            smallvec![Qubit(0)],
+                        )],
+                        Param::Float(phase),
+                    )
+                    .expect("unexpected Qiskit python bug"),
+                )
+            }
         }
     }
 
@@ -2335,6 +2373,12 @@ impl Operation for StandardGate {
                 }
                 _ => None,
             },
+            Self::RV => match params {
+                [Param::Float(v_x), Param::Float(v_y), Param::Float(v_z)] => {
+                    Some(gate_matrix::rv_gate(*v_x, *v_y, *v_z))
+                }
+                _ => None,
+            },
             Self::CH => None,
             Self::CX => None,
             Self::CY => None,

qiskit/circuit/library/__init__.py

@@ -886,7 +886,6 @@
     GRX,
     GRY,
     GRZ,
-    RVGate,
     PauliGate,
     LinearFunction,
     Isometry,

qiskit/circuit/library/generalized_gates/__init__.py

@@ -18,7 +18,6 @@
 from .gms import GMS, MSGate
 from .gr import GR, GRX, GRY, GRZ
 from .pauli import PauliGate
-from .rv import RVGate
 from .linear_function import LinearFunction
 from .isometry import Isometry
 from .uc import UCGate

qiskit/circuit/library/standard_gates/__init__.py

@@ -18,6 +18,7 @@
 from .i import IGate
 from .p import PhaseGate, CPhaseGate, MCPhaseGate
 from .r import RGate
+from .rv import RVGate
 from .rx import RXGate, CRXGate
 from .rxx import RXXGate
 from .ry import RYGate, CRYGate
@@ -109,6 +110,7 @@ def get_standard_gate_name_mapping():
         PhaseGate(theta),
         RCCXGate(),
         RC3XGate(),
+        RVGate(theta, phi, lambda_),
         RXGate(theta),
         RXXGate(theta),
         RYGate(theta),