This command is used to apply a given 1-qubit operation to the qubits
specified by bit labels.
U (bit labels, (a b)(c d));
where bit labels are given by the text in the style of ``1-6'' (qubit 1
to qubit 6) and/or ``1 3 5'' (qubit 1, 3, and 5), and (a b)(c d) is
regarded as the matrix
a,...,d may be complex numbers.
U (1 2 4-7, (0 -i)(i 0));
When a user defines a matrix A by ``matrix A (a b)(c d);''
(See also Sec. 7.1) prior to the invocation of U(...), then
U(bit labels, A);
may be used. However, in this case, one should use
The matrix may be an intrinsic matrix ``X'', ``Rx(angle)'', etc., e.g.,