Struct ParameterShiftRule 

pub struct ParameterShiftRule {
    pub shift: f64,
}

Parameter-shift rule for quantum gradient estimation.

For a parametric gate U(θ), the gradient can be computed as: ∂⟨H⟩/∂θ = (⟨H⟩(θ+s) - ⟨H⟩(θ-s)) / (2 sin(s))

where s is typically π/2.

Fields

shift: f64

Shift amount (default: π/2)

Implementations

impl ParameterShiftRule

pub const fn new() -> Self

Create a new parameter-shift rule with default shift (π/2)

pub const fn with_shift(shift: f64) -> Self

Create with custom shift

pub fn compute_gradient<F>(&self, energy_fn: F, params: &[f64]) -> Vec<f64>

where F: Fn(&[f64]) -> f64,

Compute gradient using parameter-shift rule

Arguments

• energy_fn - Function that computes energy expectation value
• params - Current parameter values

Returns

Vector of gradient components

Trait Implementations

impl Default for ParameterShiftRule

fn default() -> Self

Returns the “default value” for a type.