Function phase_rotation_operator_multivar 

pub fn phase_rotation_operator_multivar(
    r: usize,
    theta: f64,
    nvariables: usize,
    target_var: usize,
) -> Result<LinearOperator<TensorDynLen, usize>>

Create a phase rotation operator for one variable in a multi-variable system.

Acts as phase rotation on target_var and identity on all other variables. The resulting operator works on interleaved quantics encoding where each site has local dimension 2^nvariables.

Arguments

• r - Number of bits (sites)
• theta - Phase angle in radians
• nvariables - Total number of variables
• target_var - Which variable to apply phase rotation to (0-indexed)

Examples

use tensor4all_quanticstransform::phase_rotation_operator_multivar;
use std::f64::consts::PI;

// Phase rotate only the x-variable of a 2-variable function f(x, y)
let op = phase_rotation_operator_multivar(4, PI / 4.0, 2, 0).unwrap();
assert_eq!(op.mpo.node_count(), 4);