Struct DynamicProgramBuilder 

pub struct DynamicProgramBuilder { /* private fields */ }

Builds a DynamicProgram from structured control flow.

Instructions append to the block being built. begin_while and begin_if open a construct that end closes; begin_else switches the innermost if to its other arm, or reopens an if that end has just closed. Every index is checked when build validates the program, so no method here panics on a bad one.

Examples

Repeat until success: prepare |+>, measure, and retry while the outcome is 1.

use prism_q::circuit::dynamic::{ClassicalExpr, DynamicProgramBuilder};
use prism_q::{Gate, simulate_program};

let mut b = DynamicProgramBuilder::new(1, 1);
b.add_gate(Gate::H, &[0]).add_measure(0, 0);
b.begin_while("retry", ClassicalExpr::Bit(0));
b.add_reset(0).add_gate(Gate::H, &[0]).add_measure(0, 0);
b.end()?;
let program = b.build()?;

let shots = simulate_program(&program).seed(42).shots(100)?;
assert!(shots.shots.iter().all(|shot| !shot[0]));

Implementations

impl DynamicProgramBuilder

pub fn new(num_qubits: usize, num_classical_bits: usize) -> Self

pub fn num_qubits(&self) -> usize

pub fn num_classical_bits(&self) -> usize

pub fn declare( &mut self, name: impl Into<String>, ty: ClassicalType, initial: ClassicalValue, ) -> VarId

Declare a variable every shot starts at initial.

pub fn variable(&self, name: &str) -> Option<VarId>

The variable declared under name, the latest one when several share it.

pub fn expr(&self, text: &str) -> Result<ClassicalExpr>

Parse an OpenQASM expression over this builder’s variables, by name, and its classical bits, read as c[i] for one bit and c for all of them as an unsigned integer.

Errors

PrismError::Parse for text that is not an expression, an unknown name, or a builtin function over a runtime value.

pub fn add_instruction(&mut self, instruction: Instruction) -> &mut Self

pub fn add_gate(&mut self, gate: Gate, targets: &[usize]) -> &mut Self

pub fn add_measure(&mut self, qubit: usize, classical_bit: usize) -> &mut Self

pub fn add_reset(&mut self, qubit: usize) -> &mut Self

pub fn append(&mut self, circuit: &Circuit) -> &mut Self

Append every instruction of circuit.

pub fn add_rotation( &mut self, kind: RotationKind, targets: &[usize], angle: ClassicalExpr, ) -> &mut Self

Apply kind to targets at the angle angle evaluates to when the block runs.

pub fn assign(&mut self, var: VarId, value: ClassicalExpr) -> &mut Self

Store value into var, converted to its declared type.

pub fn begin_while(&mut self, name: impl Into<String>, condition: ClassicalExpr)

Open a loop that runs its body while condition is truthy, testing it before each pass. name labels the loop in the step-limit error.

pub fn begin_if(&mut self, condition: ClassicalExpr)

Open a branch whose body runs when condition is truthy.

pub fn begin_else(&mut self) -> Result<()>

Switch the innermost open if to its else arm, or reopen the if that Self::end closed last when nothing has been appended since.

Errors

PrismError::InvalidParameter when there is no such if, or it already has an else.

pub fn end(&mut self) -> Result<()>

Close the innermost while or if.

Errors

PrismError::InvalidParameter when nothing is open.

pub fn break_loop(&mut self) -> Result<()>

Leave the innermost while.

Errors

PrismError::InvalidParameter outside a loop.

pub fn continue_loop(&mut self) -> Result<()>

Skip to the next test of the innermost while condition.

Errors

PrismError::InvalidParameter outside a loop.

pub fn build(self) -> Result<DynamicProgram>

Finish the program, dropping unreachable blocks and merging each straight-line run of blocks into one, so fusion sees the longest circuits the control flow allows.

Errors

PrismError::InvalidParameter while a while or if is still open, and anything DynamicProgram::new rejects.