Command line

qso <command> [options]. Every command accepts --json for machine-readable output; qso <command> --help lists all options.

Graphs are given as specifications (see Graphs), for example metatron, fruit-of-life, petersen, hypercube:8, johnson:7,3 or random-regular:16,3,1, or as files: an edge list, or GraphML for .graphml and .xml (file:PATH forces a file).

$ qso graph fruit-of-life
Fruit of Life (contact graph)
  nodes 13, edges 18, degree 1..6, connected true, bipartite false
  diameter Some(4), triangles 6, algebraic connectivity 0.585786
  |Aut| = 12 (log10 1.079), orbits 3

$ qso iso shrikhande rook:4x4
Shrikhande and rook(4x4) are not isomorphic

$ qso transfer --graph path:4 --t-max 30
P4: no perfect state transfer 0 → 3 (strongly cospectral: true); best fidelity 0.992357 at t = 28.099259 within [0, 30]

$ qso hitting --graph cycle:64
C64: Szegedy quantum hitting time 16, classical hitting time 682.5000

$ qso qaoa --graph petersen --p 4 --layerwise
p=1  <C>=10.386751  C_max=12  ratio=0.865563  P(optimal)=0.1682  most likely 1110001011 (cut 12)
p=2  <C>=11.105320  C_max=12  ratio=0.925443  P(optimal)=0.4490  most likely 1110001011 (cut 12)
p=3  <C>=11.648892  C_max=12  ratio=0.970741  P(optimal)=0.7626  most likely 1100110110 (cut 12)
p=4  <C>=11.936517  C_max=12  ratio=0.994710  P(optimal)=0.9767  most likely 1001101101 (cut 12)

qasm runs a program exactly, mid-circuit measurements and conditions included, and samples its classical bits (every qubit if it has none). The OpenQASM 3 teleportation example of the OpenQASM project sends U(0.3, 0.2, 0.1)|0⟩, so bit 2 (the left digit) reads 1 with probability sin²(0.15) = 0.022:

$ qso qasm teleport.qasm --shots 1000 --seed 2
3 qubits, 3 bits, 15 operations, backend program
  000  258
  001  245
  011  245
  010  239
  111  5
  100  4
  101  2
  110  2

With --noise or --device the program must be a circuit; --export qasm2 or --export qasm3 prints the program in that version instead of running it.

Device files are JSON (see Noise). With a device, estimate prints the estimate, the noiseless value for comparison and the mitigated estimates. For a three-qubit GHZ state on the example device (metatron-qso-rs/examples/devices/toy_device.json):

$ qso estimate ghz.qasm --observable "Z0 Z1 + Z1 Z2" --device toy_device.json --shots 50000
<H> = 1.738600 ± 0.003859 (95% CI [1.731036, 1.746164], 50000 samples)
noiseless <H> = 2.000000

$ qso estimate ghz.qasm --observable "Z0 Z1 + Z1 Z2" --device toy_device.json --shots 50000 \
      --mitigate-readout --zne 1,3,5
<H> (readout mitigated) = 1.963079 ± 0.004379 (95% CI [1.954496, 1.971662], 50000 samples)
noiseless <H> = 2.000000
ZNE ([1.0, 3.0, 5.0]) <H> = 1.998613 ± 0.010336 (95% CI [1.978355, 2.018871], 150000 samples)

molecule reads an FCIDUMP file (see Electronic structure) and trotter builds a product-formula circuit (see Hamiltonian simulation):

$ qso molecule beh2_sto3g.fcidump --mapping parity --two-qubit-reduction --method adapt
7 orbitals, 3 + 3 electrons; 12 qubits (parity, two-qubit reduction), 666 Pauli terms
Hartree–Fock   -15.5603349360
full CI        -15.5951823567
ADAPT-VQE      -15.5948030942  (36 parameters, error vs full CI 3.79e-4)

$ qso trotter --hamiltonian "Z0 Z1 + Z1 Z2 + 0.7 X0 + 0.7 X1 + 0.7 X2" --time 2 --steps 20 --order 4
order 4, 20 steps, t = 2: 801 gates, depth 501, error bound 2.286e-2, largest column error 5.687e-6 (a lower bound on ‖U − exp(−iHt)‖)