add reagent mixing

      Transformed array of ids

    """

    source = list(map(lambda x: x.split('>')[0] + '>' + x.split('>')[1], X))

    reactant = list(map(lambda x: x.split('>')[0], X))

    reagent = list(map(lambda x: x.split('>')[1], X))

    product = list(map(lambda x: x.split('>')[2], X))

    target = list(map(lambda x: x.split('>')[2], X))

    if sep_reagent:

      source = [x + '>' + y for x,y in zip(reactant, reagent)]

    else:

      source = [x + '.' + y + '>' if y is not '' else x + '>' + y for x,y in zip(reactant, reagent)]

    target = product 

    X = np.column_stack((source, target))