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| """ | |
| qasm.py - Functions to parse a set of qasm commands into a SymPy Circuit. | |
| Examples taken from Chuang's page: https://web.archive.org/web/20220120121541/https://www.media.mit.edu/quanta/qasm2circ/ | |
| The code returns a circuit and an associated list of labels. | |
| from sympy.physics.quantum.qasm import Qasm | |
| q = Qasm('qubit q0', 'qubit q1', 'h q0', 'cnot q0,q1') | |
| q.get_circuit() | |
| CNOT(1,0)*H(1) | |
| q = Qasm('qubit q0', 'qubit q1', 'cnot q0,q1', 'cnot q1,q0', 'cnot q0,q1') | |
| q.get_circuit() | |
| CNOT(1,0)*CNOT(0,1)*CNOT(1,0) | |
| """ | |
| __all__ = [ | |
| 'Qasm', | |
| ] | |
| from math import prod | |
| from sympy.physics.quantum.gate import H, CNOT, X, Z, CGate, CGateS, SWAP, S, T,CPHASE | |
| from sympy.physics.quantum.circuitplot import Mz | |
| def read_qasm(lines): | |
| return Qasm(*lines.splitlines()) | |
| def read_qasm_file(filename): | |
| return Qasm(*open(filename).readlines()) | |
| def flip_index(i, n): | |
| """Reorder qubit indices from largest to smallest. | |
| >>> from sympy.physics.quantum.qasm import flip_index | |
| >>> flip_index(0, 2) | |
| 1 | |
| >>> flip_index(1, 2) | |
| 0 | |
| """ | |
| return n-i-1 | |
| def trim(line): | |
| """Remove everything following comment # characters in line. | |
| >>> from sympy.physics.quantum.qasm import trim | |
| >>> trim('nothing happens here') | |
| 'nothing happens here' | |
| >>> trim('something #happens here') | |
| 'something ' | |
| """ | |
| if '#' not in line: | |
| return line | |
| return line.split('#')[0] | |
| def get_index(target, labels): | |
| """Get qubit labels from the rest of the line,and return indices | |
| >>> from sympy.physics.quantum.qasm import get_index | |
| >>> get_index('q0', ['q0', 'q1']) | |
| 1 | |
| >>> get_index('q1', ['q0', 'q1']) | |
| 0 | |
| """ | |
| nq = len(labels) | |
| return flip_index(labels.index(target), nq) | |
| def get_indices(targets, labels): | |
| return [get_index(t, labels) for t in targets] | |
| def nonblank(args): | |
| for line in args: | |
| line = trim(line) | |
| if line.isspace(): | |
| continue | |
| yield line | |
| return | |
| def fullsplit(line): | |
| words = line.split() | |
| rest = ' '.join(words[1:]) | |
| return fixcommand(words[0]), [s.strip() for s in rest.split(',')] | |
| def fixcommand(c): | |
| """Fix Qasm command names. | |
| Remove all of forbidden characters from command c, and | |
| replace 'def' with 'qdef'. | |
| """ | |
| forbidden_characters = ['-'] | |
| c = c.lower() | |
| for char in forbidden_characters: | |
| c = c.replace(char, '') | |
| if c == 'def': | |
| return 'qdef' | |
| return c | |
| def stripquotes(s): | |
| """Replace explicit quotes in a string. | |
| >>> from sympy.physics.quantum.qasm import stripquotes | |
| >>> stripquotes("'S'") == 'S' | |
| True | |
| >>> stripquotes('"S"') == 'S' | |
| True | |
| >>> stripquotes('S') == 'S' | |
| True | |
| """ | |
| s = s.replace('"', '') # Remove second set of quotes? | |
| s = s.replace("'", '') | |
| return s | |
| class Qasm: | |
| """Class to form objects from Qasm lines | |
| >>> from sympy.physics.quantum.qasm import Qasm | |
| >>> q = Qasm('qubit q0', 'qubit q1', 'h q0', 'cnot q0,q1') | |
| >>> q.get_circuit() | |
| CNOT(1,0)*H(1) | |
| >>> q = Qasm('qubit q0', 'qubit q1', 'cnot q0,q1', 'cnot q1,q0', 'cnot q0,q1') | |
| >>> q.get_circuit() | |
| CNOT(1,0)*CNOT(0,1)*CNOT(1,0) | |
| """ | |
| def __init__(self, *args, **kwargs): | |
| self.defs = {} | |
| self.circuit = [] | |
| self.labels = [] | |
| self.inits = {} | |
| self.add(*args) | |
| self.kwargs = kwargs | |
| def add(self, *lines): | |
| for line in nonblank(lines): | |
| command, rest = fullsplit(line) | |
| if self.defs.get(command): #defs come first, since you can override built-in | |
| function = self.defs.get(command) | |
| indices = self.indices(rest) | |
| if len(indices) == 1: | |
| self.circuit.append(function(indices[0])) | |
| else: | |
| self.circuit.append(function(indices[:-1], indices[-1])) | |
| elif hasattr(self, command): | |
| function = getattr(self, command) | |
| function(*rest) | |
| else: | |
| print("Function %s not defined. Skipping" % command) | |
| def get_circuit(self): | |
| return prod(reversed(self.circuit)) | |
| def get_labels(self): | |
| return list(reversed(self.labels)) | |
| def plot(self): | |
| from sympy.physics.quantum.circuitplot import CircuitPlot | |
| circuit, labels = self.get_circuit(), self.get_labels() | |
| CircuitPlot(circuit, len(labels), labels=labels, inits=self.inits) | |
| def qubit(self, arg, init=None): | |
| self.labels.append(arg) | |
| if init: self.inits[arg] = init | |
| def indices(self, args): | |
| return get_indices(args, self.labels) | |
| def index(self, arg): | |
| return get_index(arg, self.labels) | |
| def nop(self, *args): | |
| pass | |
| def x(self, arg): | |
| self.circuit.append(X(self.index(arg))) | |
| def z(self, arg): | |
| self.circuit.append(Z(self.index(arg))) | |
| def h(self, arg): | |
| self.circuit.append(H(self.index(arg))) | |
| def s(self, arg): | |
| self.circuit.append(S(self.index(arg))) | |
| def t(self, arg): | |
| self.circuit.append(T(self.index(arg))) | |
| def measure(self, arg): | |
| self.circuit.append(Mz(self.index(arg))) | |
| def cnot(self, a1, a2): | |
| self.circuit.append(CNOT(*self.indices([a1, a2]))) | |
| def swap(self, a1, a2): | |
| self.circuit.append(SWAP(*self.indices([a1, a2]))) | |
| def cphase(self, a1, a2): | |
| self.circuit.append(CPHASE(*self.indices([a1, a2]))) | |
| def toffoli(self, a1, a2, a3): | |
| i1, i2, i3 = self.indices([a1, a2, a3]) | |
| self.circuit.append(CGateS((i1, i2), X(i3))) | |
| def cx(self, a1, a2): | |
| fi, fj = self.indices([a1, a2]) | |
| self.circuit.append(CGate(fi, X(fj))) | |
| def cz(self, a1, a2): | |
| fi, fj = self.indices([a1, a2]) | |
| self.circuit.append(CGate(fi, Z(fj))) | |
| def defbox(self, *args): | |
| print("defbox not supported yet. Skipping: ", args) | |
| def qdef(self, name, ncontrols, symbol): | |
| from sympy.physics.quantum.circuitplot import CreateOneQubitGate, CreateCGate | |
| ncontrols = int(ncontrols) | |
| command = fixcommand(name) | |
| symbol = stripquotes(symbol) | |
| if ncontrols > 0: | |
| self.defs[command] = CreateCGate(symbol) | |
| else: | |
| self.defs[command] = CreateOneQubitGate(symbol) | |