Q-Sylvan

Q-Sylvan extends the parallel decision diagram library Sylvan (v1.8.0) with QMDDs (i.e. factored EVBDDs with complex edge weights), as well as functionality to simulate quantum circuits. This is currently still a beta version.

Installation

Dependencies

Q-Sylvan requires the following libraries: popt, GMP, MPFR and MPC. On Ubuntu it should be possible to install these with

• sudo apt-get install libpopt-dev
• sudo apt-get install libgmp-dev
• sudo apt-get install libmpfr-dev
• sudo apt-get install libmpc-dev
• sudo apt-get install cmake

Compiling the code

After downloading or cloning the repository, from the repository folder the code can be compiled with:

1. mkdir build
2. cd build
3. cmake ..
4. make

Test can be run with ctest.

Simulations of circuits presented in qasm on QMDD and MTBDD

Running can be activated with ./run_qasm_on_qmdd <filename>.qasm --state-vector in build/qasm/ directory.

For MTBDD type ./run_qasm_on_mtbdd <filename>.qasm --state-vector in build/qasm directory.

Debugging can be activated with gdb ./run_qasm_on_qmdd in build/qasm directory.

The GNU GDB Debugger accepts commands as (gdb) run <filename>.qasm --state-vector.

Tests of the simulators based on QMDD and MTBDD

Running tests can be activated with pytest -v in the root directory, Q-Sylvan/q-sylvan/.

Example usage

The following code snippets are a toy example for creating the Bell state |Phi^+> = 1/sqrt(2) (|01> + |10>), first in the C interface, and secondly in the QASM interface.

C interface

// Create |Phi^+>
int nqubits = 2;
QMDD state = qmdd_create_all_zero_state(nqubits);
state = qmdd_gate(state, GATEID_H, 0);     // H on q0
state = qmdd_cgate(state, GATEID_X, 0, 1); // CNOT on c=q0, t=q1
state = qmdd_gate(state, GATEID_X, 0);     // X on q0

// Measure state
bool outcome[] = {0, 0};
double prob;
qmdd_measure_all(state, nqubits, outcome, &prob);

This code can be found in examples/bell_state.c and after compiling the code as described above can be run with ./examples/bell_state from the build/ directory. A more complete set of available functions can be found here.

QASM interface

OPENQASM 2.0;
include "qelib1.inc";

// 2 qubit quantum register and 2 bit classical register
qreg q[2];
creg c[2];

// Create |Phi^+>
h q[0];
cx q[0], q[1];
x q[0];

// Measure state
measure q[0]->c[0];
measure q[1]->c[1];

This code can be found in qasm/circuits/bell_state.qasm and can be run with ./build/qasm/run_qasm_on_qmdd qasm/circuits/bell_state.qasm. All gates specified in qelib1.inc are supported, as well as measurements. Custom definitions of gates and classical conditioning are currently not supported.

Documentation

A more complete documentation of the C interface can be found here.

Acknowledgements

This work is supported by the NEASQC project, funded by the European Union's Horizon 2020 programme, Grant Agreement No. 951821.