8.5 How do I play with the compositions?

For variable-composition and single block calculations, as soon as the calculation starts, it produces a file Seeds/compositions with all possible compositions, from which the code randomly takes compositions for the random structure generator. You can edit this file, leaving the compositions you are most interested in — only these compositions will be used for random structure production in the second and subsequent generations. Seeds/compositions file lists the numbers of atoms of each type in the cell, e.g., for the C-O system:

    8 0
    0 8
    2 4

means that you are interested in randomly producing C$_8$, O$_8$, and C$_2$O$_4$ structures. Other compositions will be sampled too, thanks to the heredity and transmutation operators.

When you want to generate structures with specific compositions, you can use the anti-compositions feature — write the list of all unwanted compositions to the file named Seeds/Anti-compositions. There are three ways to do so:

  1. For all unwanted compositions with the same ratios, you can write stoichiometric ratio to ban these compositions. For example, you can use “1 2 1” to ban all the composition with the same ratio, such as “1 2 1”, “2 4 2”, “3 6 3” and so on.

  2. Only for the specific composition, but not for other compositions with the same ratio. You can write the compositions with a minus sign. For example, you can use “-3 2 0” or “3 -2 0” to ban the “3 2 0” composition, but not to ban “6 4 0” or “9 6 0” composition. (Notice: “3 2 -0” does not work for this case).

  3. For all single/binary/ternary compounds. If you don’t want to sample all single/binary/ternary compounds, just write the keyword single/binary/ternary in Anti-compositions file.


    1 1 2
   -2 2 1

If you don’t clearly know what you are doing, please leave Anti-compositions file empty. For more information about the compositions you don’t want, you can have a look at results1/compositionStatistic file.