Hello,
I have a compound with formula AxB1-xC1+xD1-x which ensures it is isoelectronic to known materials. A and B are cations and A,B occupy one kind of lattice sites; C and D are anions and C,D occupy another kind of lattice sites(I have written this in my lat.in). I want to keep the constrain of concentration when I run mmaps.
I tryied different crange.in:
2.0A+1.0B-1.0C<=0.03
2.0A+1.0B-1.0C>=-0.03
or
1.0B-1.0D<=0.03
1.0B-1.0D>=-0.03
But mmaps will generate 8 structures and then stop generating new structures. I want to do CE on this "line" because I want to constrain the ratio to find the ground state of electronic equivalents.
It took more than a week and still did not generate new structures. I want to CE on "a line" in this system. What is the algorithm for generating structures in mmaps?
mmaps should not "just stop" generating structures. Sometimes it just take a while (constraints make the enumeration appear slower because a lot of structure are excluded). Beware that excluding structures outside a certain narrow composition range might accidentally generate a cluster expansion that assigns a very low energy to other structures not in your concentration range. This has been discussion elsewhere on this forum.
I have recently been trying to run a similar "line" over an alloy between two ternary materials, with three possible species sharing the same site.
I find that the structure search becomes very slow after 12 calculations (i.e. no new structures for >48h). This is strange as my previous cluster expansion runs on the end groups generated many different clusters in order to explore the ground-state structure. Could MMAPS be excessively focusing on the search for intermediate mixtures? Would it be helpful to "seed" the run with structures and energies from explorations of the end groups? Or will MMAPS ultimately need to find some large structures in order to ever get ESIs for the remaining interactions?
Without more information, I can only speculate that the delay in generating structure is due to the fact that structures that satisfy all the stated constraints must be very large.
Also: make sure that the set of allowed composition still has a positive "volume" in composition space. If not, the code may not be able to determine some interactions.