Function createDiagonalOpFromPauliHamilFile

pub unsafe extern "C" fn createDiagonalOpFromPauliHamilFile(
    fn_: *mut c_char,
    env: QuESTEnv,
) -> DiagonalOp

Creates and initialiases a diagonal operator from the Z Pauli Hamiltonian encoded in file with filename \p fn.

This is a convenience function to prepare a diagonal operator from a plaintext description of an all-Z Pauli Hamiltonian. The returned ::DiagonalOp is a distributed data structure, and significantly faster to use (through functions like calcExpecDiagonalOp()) than ::PauliHamil functions (like calcExpecPauliHamil()).

• See createDiagonalOp() for info about the returned operator.
• See initDiagonalOpFromPauliHamil() for info about the initialised state.
• See createPauliHamilFromFile() for info about the required file format.

The returned ::DiagonalOp must be later freed with destroyDiagonalOp(). Note a ::PauliHamil from \p fn is temporarily internally created.

This function is equivalent to

// produce diagonal matrix d
PauliHamil h = createPauliHamilFromFile(fn);
DiagonalOp d = createDiagonalOp(h.numQubits, env);
initDiagonalOpFromPauliHamil(d, h);
destroyPauliHamil(h);

@see

• initDiagonalOpFromPauliHamil()
• createPauliHamilFromFile()
• createDiagonalOp()
• destroyDiagonalOp()

@ingroup type @param[in] fn filename of a plaintext file encoding an all-Z Pauli Hamiltonian @param[in] env the session ::QuESTEnv @returns a created ::DiagonalOp equivalent to the Hamiltonian in \p fn @throws invalidQuESTInputError()

• if file \p fn cannot be read
• if file \p fn does not encode a valid ::PauliHamil
• if the encoded ::PauliHamil consists of operators other than PAULI_Z and PAULI_I @author Tyson Jones @author Milos Prokop (serial prototype)