'Reduces the atom to an affine expression and list of constraints.
Parameters
arg_objs : list
LinExpr for each argument.
size : tuple
The size of the resulting expression.
data :
Additional data required by the atom.
Returns
tuple
(LinOp for objective, list of constraints)'

@staticmethod
def graph_implementation(arg_objs, size, data=None):

    x = arg_objs[0]
    y = arg_objs[1]
    v = lu.create_var((1, 1))
    two = lu.create_const(2, (1, 1))
    constraints = [SOC(lu.sum_expr([y, v]), [lu.sub_expr(y, v), lu.mul_expr(two, x, x.size)]), lu.create_geq(y)]
    return (v, constraints)
