Struct TensorNetwork 

pub struct TensorNetwork { /* private fields */ }

Tensor network representation of a quantum circuit

Implementations

impl TensorNetwork

pub fn new() -> Self

Create a new empty tensor network

Examples found in repository

examples/tensor_network_demo.rs (line 50)

fn demo_basic_tensor_network() -> quantrs2_core::error::QuantRS2Result<()> {
    println!("--- Basic Tensor Network Construction ---");

    // Create simple tensors
    let identity = Tensor::identity(2, "in".to_string(), "out".to_string());
    println!(
        "Created identity tensor: rank={}, size={}",
        identity.rank(),
        identity.size()
    );

    // Create Hadamard tensor
    let h_data = vec![
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(-1.0 / 2.0_f64.sqrt(), 0.0),
    ];
    let h_tensor = Tensor::new(
        h_data,
        vec![2, 2],
        vec!["h_in".to_string(), "h_out".to_string()],
    );

    // Build tensor network
    let mut tn = TensorNetwork::new();
    let id_idx = tn.add_tensor(identity);
    let h_idx = tn.add_tensor(h_tensor);

    // Connect tensors
    tn.add_bond(id_idx, "out".to_string(), h_idx, "h_in".to_string())?;

    println!("Built tensor network with {} tensors and {} bonds", 2, 1);
    println!();

    Ok(())
}

pub fn add_tensor(&mut self, tensor: Tensor) -> usize

Add a tensor to the network

Examples found in repository

examples/tensor_network_demo.rs (line 51)

fn demo_basic_tensor_network() -> quantrs2_core::error::QuantRS2Result<()> {
    println!("--- Basic Tensor Network Construction ---");

    // Create simple tensors
    let identity = Tensor::identity(2, "in".to_string(), "out".to_string());
    println!(
        "Created identity tensor: rank={}, size={}",
        identity.rank(),
        identity.size()
    );

    // Create Hadamard tensor
    let h_data = vec![
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(-1.0 / 2.0_f64.sqrt(), 0.0),
    ];
    let h_tensor = Tensor::new(
        h_data,
        vec![2, 2],
        vec!["h_in".to_string(), "h_out".to_string()],
    );

    // Build tensor network
    let mut tn = TensorNetwork::new();
    let id_idx = tn.add_tensor(identity);
    let h_idx = tn.add_tensor(h_tensor);

    // Connect tensors
    tn.add_bond(id_idx, "out".to_string(), h_idx, "h_in".to_string())?;

    println!("Built tensor network with {} tensors and {} bonds", 2, 1);
    println!();

    Ok(())
}

pub fn add_bond( &mut self, t1: usize, idx1: String, t2: usize, idx2: String, ) -> QuantRS2Result<()>

Connect two tensor indices

Examples found in repository

examples/tensor_network_demo.rs (line 55)

fn demo_basic_tensor_network() -> quantrs2_core::error::QuantRS2Result<()> {
    println!("--- Basic Tensor Network Construction ---");

    // Create simple tensors
    let identity = Tensor::identity(2, "in".to_string(), "out".to_string());
    println!(
        "Created identity tensor: rank={}, size={}",
        identity.rank(),
        identity.size()
    );

    // Create Hadamard tensor
    let h_data = vec![
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(1.0 / 2.0_f64.sqrt(), 0.0),
        C64::new(-1.0 / 2.0_f64.sqrt(), 0.0),
    ];
    let h_tensor = Tensor::new(
        h_data,
        vec![2, 2],
        vec!["h_in".to_string(), "h_out".to_string()],
    );

    // Build tensor network
    let mut tn = TensorNetwork::new();
    let id_idx = tn.add_tensor(identity);
    let h_idx = tn.add_tensor(h_tensor);

    // Connect tensors
    tn.add_bond(id_idx, "out".to_string(), h_idx, "h_in".to_string())?;

    println!("Built tensor network with {} tensors and {} bonds", 2, 1);
    println!();

    Ok(())
}

pub fn contract_all(&self) -> QuantRS2Result<Tensor>

Contract the entire network to a single tensor

Examples found in repository

examples/tensor_network_demo.rs (line 237)

fn demo_tensor_contraction() -> quantrs2_core::error::QuantRS2Result<()> {
    println!("--- Tensor Contraction Optimization ---");

    // Create a circuit with specific structure
    let mut circuit = Circuit::<4>::new();

    // Layer 1: Single-qubit gates
    for i in 0..4 {
        circuit.add_gate(Hadamard { target: QubitId(i) })?;
    }

    // Layer 2: Entangling gates
    circuit.add_gate(CNOT {
        control: QubitId(0),
        target: QubitId(1),
    })?;
    circuit.add_gate(CNOT {
        control: QubitId(2),
        target: QubitId(3),
    })?;

    // Layer 3: Cross entangling
    circuit.add_gate(CNOT {
        control: QubitId(1),
        target: QubitId(2),
    })?;

    // Convert to tensor network
    let converter = CircuitToTensorNetwork::<4>::new()
        .with_max_bond_dim(8)
        .with_tolerance(1e-12);

    let tn = converter.convert(&circuit)?;

    println!("Converted circuit to tensor network");
    println!("Network has {} tensors", circuit.num_gates());

    // Contract the network
    let result = tn.contract_all()?;
    println!("Contracted to single tensor of rank {}", result.rank());

    println!();
    Ok(())
}

pub fn compress( &mut self, max_bond_dim: usize, tolerance: f64, ) -> QuantRS2Result<()>

Apply SVD-based compression

Trait Implementations

impl Debug for TensorNetwork

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.