Struct SumOp 

pub struct SumOp {
    pub terms: Vec<PauliString>,
}

A vector of Pauli strings that are summed together. Useful for representing Hamiltonians or observables.

Fields

• terms - A vector of PauliString instances that are summed together.

Fields

terms: Vec<PauliString>

A vector of Pauli strings that are summed together.

Implementations

impl SumOp

pub fn new(terms: Vec<PauliString>) -> Self

Creates a new SumPauliString instance with the given terms and number of qubits.

Arguments

• terms - A vector of PauliString instances that are summed together.

Returns

• A new SumPauliString instance with the specified terms and number of qubits.

pub fn num_terms(&self) -> usize

Returns the number of terms in the sum.

Returns

• usize - The number of terms in the sum.

pub fn add_term(&mut self, term: PauliString)

Adds a new term to the sum.

Arguments

• term - The PauliString term to be added to the sum.

pub fn with_term(self, term: PauliString) -> Self

Adds a new term to the sum and returns a new SumOp instance.

Arguments

• term - The PauliString term to be added to the sum.

Returns

• Self - A new SumOp instance with the added term.

pub fn apply(&self, state: &State) -> Result<State, Error>

Applies the sum of Pauli strings to a given state.

Arguments

• state - The state to which the sum of Pauli strings is applied.

Returns

• Result<State, Error> - The resulting state after applying the sum of Pauli strings, or an error if the operation fails.

Errors

• Returns an error if the operations in the Pauli strings refer to qubits outside the range of the state.

pub fn expectation_value(&self, state: &State) -> Result<Complex<f64>, Error>

Calculates the expectation value <psi|H|psi> = Sum_i <psi|P_i|psi>.

The expectation value is generally real for Hermitian operators and normalised states. However, this function returns a Complex<f64> as intermediate PauliStrings might have complex coefficients or the operator/state might not be strictly physical.

Arguments

• state - The state |psi> for which to calculate the expectation value. For a physically meaningful expectation value, this state should be normalised.

Returns

• Result<Complex<f64>, Error> - The expectation value, or an error if the operation fails.

Errors

• Returns an error if any underlying PauliString::apply fails (eg., invalid qubit index).
• Returns an error if state.inner_product fails (eg., mismatched number of qubits, though PauliString::apply should also catch qubit count issues).

Trait Implementations

impl Add<PauliString> for SumOp

type Output = SumOp

The resulting type after applying the + operator.

fn add(self, other: PauliString) -> Self::Output

Performs the + operation.

impl Add for SumOp

type Output = SumOp

The resulting type after applying the + operator.

fn add(self, other: Self) -> Self::Output

Performs the + operation.

impl Clone for SumOp

fn clone(&self) -> SumOp

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SumOp

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

Formats the value using the given formatter.

impl Display for SumOp

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

Formats the value using the given formatter.

impl Mul<Complex<f64>> for SumOp

type Output = SumOp

The resulting type after applying the * operator.

fn mul(self, rhs: Complex<f64>) -> Self::Output

Performs the * operation.

impl Mul<f64> for SumOp

type Output = SumOp

The resulting type after applying the * operator.

fn mul(self, rhs: f64) -> Self::Output

Performs the * operation.

impl PartialEq for SumOp

fn eq(&self, other: &SumOp) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for SumOp