Finish implementing OpenQASM parser about tweedledum

[Roland-djee]

Hi @boschmitt , I'd be happy to use that functionality. Any updates on this ?

[boschmitt]

Hi @Roland-djee.

There is already some limited support for OpenQASM 2.0.

I suppose the further support would require bigger architectural changes to tweedledum, i.e., possibly creating a AST and a global context capable of handling various circuits inside a bigger program. Also, there is the newer OpenQASM 3.0 version that is still in development phase.

[Roland-djee]

Yes, concretely, I would like to use the Exorcism implementation. However, it requires input esops as strings (unless I missed something) which can be produced by traversing an AST of some sort. I was wondering if there were already such a functionality for OpenQASM format.

[boschmitt]

exorcism works form an ESOP defined as a vector of cubes or from a truth table.

If you have a function: f(abc) = a!c ⊕ abc, then your ESOP will be [Cube(‘1-0’), Cube(‘111’)]
(Note that ‘b’ does not appear in the first cube, hence the use of ‘-‘)

For example (from python):

from tweedledum.classical import TruthTable, Cube, create_from_cubes, exorcism

esop = [Cube('101'), Cube('100'), Cube('011'), Cube('001'), Cube('000')]
opt_esop = exorcism(esop, 3)
for cube in opt_esop:
    print(cube.to_string(3))

# Create a TruthTable from the orginal ESOP:
tt_esop = TruthTable(3)
create_from_cubes(tt_esop, esop, True)

# Create a TruthTable from the optimized orginal ESOP:
tt_opt_esop = TruthTable(3)
create_from_cubes(tt_opt_esop, opt_esop, True)

# Make sure they are the same
print(tt_esop == tt_opt_esop)

# Now, from a function TruthTable do exorcism (it will extract a PKRM and then do exorcism)
opt_esop_2 = exorcism(tt_opt_esop)
for cube in opt_esop_2:
    print(cube.to_string(3))

[Roland-djee]

Hi @boschmitt thanks. Yes, I am aware of this. I am just scratching my head around how to parse structures (ie. circuits) to generate these vectors of cubes. It looks like there is no other way than an AST of some sort.