# build up the expression from sub-expressions
sub_expr1 = Variable("_a", latex_format = r"{_{-}a}")
sub_expr2 = Variable("_b", latex_format = r"{_{-}b}")
sub_expr3 = Add(t, one)
sub_expr4 = Add(sub_expr2, t)
sub_expr5 = Interval(sub_expr3, Add(t, _s))
sub_expr6 = Add(Neg(t), one)
expr = Qcircuit(vert_expr_array = VertExprArray([ExprRange(sub_expr1, Input(state = ket_plus), one, t), ExprRange(sub_expr1, MultiQubitElem(element = Input(state = _ket_u, part = sub_expr1), targets = sub_expr5), one, _s)], ExprRange(sub_expr2, [ExprRange(sub_expr1, ConditionalSet(Conditional(MultiQubitElem(element = CONTROL, targets = Set(sub_expr3)), Equals(sub_expr4, sub_expr1)), Conditional(Igate, NotEquals(sub_expr4, sub_expr1))), one, t).with_case_simplification(), ExprRange(sub_expr1, MultiQubitElem(element = Gate(operation = MatrixExp(_U, Exp(two, Neg(sub_expr2))), part = sub_expr1), targets = sub_expr5), one, _s)], sub_expr6, zero).with_decreasing_order(), [ExprRange(sub_expr1, Output(state = ScalarMult(frac(one, sqrt(two)), VecAdd(ket0, ScalarMult(Exp(e, Mult(two, pi, i, Exp(two, Neg(sub_expr1)), _phase)), ket1)))), sub_expr6, zero).with_decreasing_order(), ExprRange(sub_expr1, MultiQubitElem(element = Output(state = _ket_u, part = sub_expr1), targets = sub_expr5), one, _s)]))