quancoms 0.1.5

A quantom computer simulator.

quancoms

A high-performance, full-state vector quantum simulator written in Rust.

"Where bitwise magic meets quantum mechanics."

Features

• $O(2^{n-k})$ Optimization: Uses a specialized Bit-Insertion Technique to skip unnecessary state scans, making controlled gates ($CNOT$, $CCNOT$, $MCU$) significantly faster than naive implementations.
• Memory Safety: Built-in exponential RAM requirement pre-check. It knows your hardware limits before it even tries to allocate.
• Comprehensive Gate Set:
• Unary: $X, H, R_x, R_y, R_z$, and the universal $U$ gate.
• Controlled: $CNOT, CCNOT, CSWAP$.
• Universal: $MCU$ (Multi-Controlled Unitary) for any $k$-control configuration
• Flexible Observation: Supports full collapse, partial measurement, and "God-eye" non-destructive probability inspection.

Quick Start

Create a Bell State ($|00\rangle + |11\rangle$)

use quancoms::qubit::QuantumRegister;

fn main() -> Result<(), String> {
   let mut reg = QuantumRegister::new(2)?;

   reg.H(0)?       // Superposition on qubit 0
      .CNOT(0, 1)?; // Entangle qubit 0 and 1

   let result = reg.observe()?;
   println!("Measured state: {:?}", result);
   Ok(())
}

Optimisation

Most simulators loop through all $2^n$ states for every gate. BIQ is different.For a gate with $k$ control qubits, we only iterate through $2^{n-(k+1)}$ subspaces. We use a "Triple Hole" (or N-Hole) injection strategy to reconstruct the target indices on the fly using bitwise XOR and shifts. Performance Gain:

Gate	Naive Loop	BIQ (Bit-Injected)
X / H / U	$2^n$	$2^{n-1}$ (2x Faster)
CNOT	$2^n$	$2^{n-2}$ (4x Faster)
CCNOT / CSWAP	$2^n$	$2^{n-3}$ (8x Faster)

Hardware limit

Quantum simulation is memory-intensive. Each additional qubit doubles the RAM requirement. | Qubits | RAM Required | Note | | 20 | 16 MiB | Runs on a toaster| | 30 | 16 GiB | Standard PC limit | | 40 | 16 TiB | Data center required| | 100 | $\infty$ | Beyond the observable universe's storage| Note: BIQ will panic! safely if your available RAM cannot accommodate the requested state vector.

Testing

We take physics seriously. Our test suite (currently 12+ passed) includes:

• Bell State correlation tests.
• GHZ State ($|000\rangle + |111\rangle$) multi-measurement consistency.
• Unitary matrix reversibility.

 cargo test