# Copyright (C) 2023 qBraid
#
# This file is part of the qBraid-SDK
#
# The qBraid-SDK is free software released under the GNU General Public License v3
# or later. You can redistribute and/or modify it under the terms of the GPL v3.
# See the LICENSE file in the project root or <https://www.gnu.org/licenses/gpl-3.0.html>.
#
# THERE IS NO WARRANTY for the qBraid-SDK, as per Section 15 of the GPL v3.
"""
Module that implements qelib1.inc qasm gate definitions as python functions
"""
import re
from typing import Optional
from .exceptions import QasmError
def _get_param(instr: str) -> Optional[str]:
try:
return instr[instr.index("(") + 1 : instr.index(")")]
except ValueError:
return None
def _remove_spaces_in_parentheses(expression):
# Find all parenthesized parts of the input.
parenthesized_parts = re.findall(r"\(.*?\)", expression)
for part in parenthesized_parts:
# For each parenthesized part, remove all the spaces.
cleaned_part = part.replace(" ", "")
# Replace the original part in the expression with the cleaned part.
expression = expression.replace(part, cleaned_part)
return expression
def _decompose_cu_instr(instr: str) -> str:
"""controlled-U gate"""
try:
instr = _remove_spaces_in_parentheses(instr)
cu_gate, qs = instr.split(" ")
a, b = qs.strip(";").split(",")
params_lst = _get_param(cu_gate).split(",")
params = [float(x) for x in params_lst]
theta, phi, lam, gamma = params
except (AttributeError, ValueError) as err:
raise QasmError from err
instr_out = "\n// cu gate\n"
instr_out += f"p({gamma}) {a};\n"
instr_out += f"p({(lam+phi)/2}) {a};\n"
instr_out += f"p({(lam-phi)/2}) {b};\n"
instr_out += f"cx {a},{b};\n"
instr_out += f"u({-1*theta/2},0,{-1*(phi+lam)/2}) {b};\n"
instr_out += f"cx {a},{b};\n"
instr_out += f"u({theta/2},{phi},0) {b};\n\n"
return instr_out
def _decompose_rxx_instr(instr: str) -> str:
"""two-qubit XX rotation"""
try:
instr = instr.replace(", ", ",")
rxx_gate, qs = instr.split(" ")
a, b = qs.strip(";").split(",")
theta = _get_param(rxx_gate)
except (AttributeError, ValueError) as err:
raise QasmError from err
instr_out = "\n// rxx gate\n"
instr_out += f"h {a};\n"
instr_out += f"h {b};\n"
instr_out += f"cx {a},{b};\n"
instr_out += f"rz({theta}) {b};\n"
instr_out += f"cx {a},{b};\n"
instr_out += f"h {b};\n"
instr_out += f"h {a};\n\n"
return instr_out
def _decompose_rccx_instr(instr: str) -> str:
"""relative-phase CCX"""
try:
_, qs = instr.split(" ")
a, b, c = qs.strip(";").split(",")
except (AttributeError, ValueError) as err:
raise QasmError from err
instr_out = "\n// rccx gate\n"
instr_out += f"u2(0,pi) {c};\n"
instr_out += f"u1(pi/4) {c};\n"
instr_out += f"cx {b},{c};\n"
instr_out += f"u1(-pi/4) {c};\n"
instr_out += f"cx {a},{c};\n"
instr_out += f"u1(pi/4) {c};\n"
instr_out += f"cx {b},{c};\n"
instr_out += f"u1(-pi/4) {c};\n"
instr_out += f"u2(0,pi) {c};\n\n"
return instr_out
def _decompose_rc3x_instr(instr: str) -> str:
"""relative-phase 3-controlled X gate"""
try:
_, qs = instr.split(" ")
a, b, c, d = qs.strip(";").split(",")
except (AttributeError, ValueError) as err:
raise QasmError from err
instr_out = "\n// rc3x gate\n"
instr_out += f"u2(0,pi) {d};\n"
instr_out += f"u1(pi/4) {d};\n"
instr_out += f"cx {c},{d};\n"
instr_out += f"u1(-pi/4) {d};\n"
instr_out += f"u2(0,pi) {d};\n"
instr_out += f"cx {a},{d};\n"
instr_out += f"u1(pi/4) {d};\n"
instr_out += f"cx {b},{d};\n"
instr_out += f"u1(-pi/4) {d};\n"
instr_out += f"cx {a},{d};\n"
instr_out += f"u1(pi/4) {d};\n"
instr_out += f"cx {b},{d};\n"
instr_out += f"u1(-pi/4) {d};\n"
instr_out += f"u2(0,pi) {d};\n"
instr_out += f"u1(pi/4) {d};\n"
instr_out += f"cx {c},{d};\n"
instr_out += f"u1(-pi/4) {d};\n"
instr_out += f"u2(0,pi) {d};\n\n"
return instr_out
[docs]
def decompose_qasm_qelib1(qasm_str: str) -> str:
"""Replace edge-case qelib1 gates with equivalent decomposition."""
qasm_lst_out = []
qasm_lst = qasm_str.split("\n")
for _, qasm_line in enumerate(qasm_lst):
line_str = qasm_line
len_line = len(line_str)
if len_line > 3 and line_str[0:3] == "cu(":
line_str_out = _decompose_cu_instr(line_str)
elif len_line > 4 and line_str[0:4] == "rxx(":
line_str_out = _decompose_rxx_instr(line_str)
elif len_line > 4 and line_str[0:4] == "rccx":
line_str_out = _decompose_rccx_instr(line_str)
elif len_line > 4 and line_str[0:4] == "rc3x":
line_str_out = _decompose_rc3x_instr(line_str)
else:
line_str_out = line_str
qasm_lst_out.append(line_str_out)
qasm_str_def = "\n".join(qasm_lst_out)
return qasm_str_def