| 1 | package tuffy.mln; |
| 2 | import java.util.*; |
| 3 | |
| 4 | import tuffy.util.StringMan; |
| 5 | |
| 6 | |
| 7 | /** |
| 8 | * An atomic formula. It's designed as a light-weight construct, hence |
| 9 | * all fields are transparent (public). |
| 10 | */ |
| 11 | public class Atom { |
| 12 | |
| 13 | /** |
| 14 | * Enumerated type of Atoms. 1) NONE; 2) EVIDENCE: atom in evidence; |
| 15 | * 3) QUERY: atom in query; 4) QUEVID: atom in query as evidence. |
| 16 | */ |
| 17 | public static enum AtomType {EVIDENCE, QUERY, NONE, QUEVID}; |
| 18 | |
| 19 | /** |
| 20 | * The predicate of this Atom. |
| 21 | */ |
| 22 | |
| 23 | public Predicate pred; |
| 24 | /** |
| 25 | * The argument list represented as a tuple of integers: |
| 26 | * constant as positive number and variable as negative number. |
| 27 | */ |
| 28 | public Tuple args = null; |
| 29 | |
| 30 | public ArrayList<String> sargs = null; |
| 31 | |
| 32 | /** |
| 33 | * Truth value of this atom. |
| 34 | */ |
| 35 | public Boolean truth = null; |
| 36 | |
| 37 | /** |
| 38 | * Probability of "soft evidence". |
| 39 | */ |
| 40 | public Double prior = null; |
| 41 | |
| 42 | /** |
| 43 | * Type of this atom. Values are enumerated by {@link AtomType}. |
| 44 | */ |
| 45 | public AtomType type = AtomType.NONE; |
| 46 | |
| 47 | /** |
| 48 | * Map the {@link AtomType} value of this atom into an integer, |
| 49 | * which is used internally by the DB. |
| 50 | */ |
| 51 | public int club() { |
| 52 | switch(type) { |
| 53 | case NONE: return 0; |
| 54 | case QUERY: return 1; |
| 55 | case EVIDENCE: return 2; |
| 56 | case QUEVID: return 3; // evidence in query |
| 57 | default: return 0; |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * Test if this atom is soft evidence. |
| 63 | */ |
| 64 | public boolean isSoftEvidence(){ |
| 65 | return prior != null; |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Return the number of grounded atoms when grounding this atom. |
| 70 | * This number equals to the multiplication of the domain size |
| 71 | * of each distinct variable appearing in this atom. That is, |
| 72 | * we assume cross product is used. |
| 73 | */ |
| 74 | public long groundSize(){ |
| 75 | long size = 1; |
| 76 | |
| 77 | // ASSUMPTION OF DATA STRUCTURE: $\forall$ i<j, args.get(i) > args.get(j) if |
| 78 | // args.get(i), args.get(j) < 0. (i.e., naming new variables |
| 79 | // sequentially from left to right. |
| 80 | int lastVar = 0; |
| 81 | for(int i=0; i<pred.arity(); i++){ |
| 82 | // if this is a new variable not seen before |
| 83 | if(args.get(i) < lastVar){ |
| 84 | Type t = pred.getTypeAt(i); |
| 85 | size *= t.size(); |
| 86 | lastVar = args.get(i); |
| 87 | } |
| 88 | } |
| 89 | return size; |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Create an evidence atom. |
| 94 | * @param p the predicate |
| 95 | * @param as the arguments |
| 96 | * @param t the truth value |
| 97 | */ |
| 98 | public Atom(Predicate p, ArrayList<Integer> as, boolean t){ |
| 99 | pred = p; |
| 100 | args = new Tuple(as); |
| 101 | |
| 102 | truth = t; |
| 103 | type = AtomType.EVIDENCE; |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * Create a soft evidence atom. |
| 108 | * Note that the type of 'soft evidence' atoms is NONE, |
| 109 | * as opposed to EVIDENCE. |
| 110 | * @param p the predicate |
| 111 | * @param as the arguments |
| 112 | * @param prior the prior probability |
| 113 | */ |
| 114 | public Atom(Predicate p, ArrayList<Integer> as, double prior){ |
| 115 | pred = p; |
| 116 | args = new Tuple(as); |
| 117 | truth = null; |
| 118 | this.prior = prior; |
| 119 | type = AtomType.NONE; |
| 120 | } |
| 121 | |
| 122 | |
| 123 | public Atom(ArrayList<String> as, double prior){ |
| 124 | pred = null; |
| 125 | sargs = as; |
| 126 | truth = null; |
| 127 | this.prior = prior; |
| 128 | type = AtomType.NONE; |
| 129 | } |
| 130 | |
| 131 | public Atom(ArrayList<String> as, boolean t){ |
| 132 | pred = null; |
| 133 | sargs = as; |
| 134 | truth = t; |
| 135 | type = AtomType.EVIDENCE; |
| 136 | } |
| 137 | |
| 138 | |
| 139 | |
| 140 | /** |
| 141 | * Create an atom of type NONE. |
| 142 | * The default truth value of unknown is null. |
| 143 | * |
| 144 | * @param p the predicate |
| 145 | * @param at the arguments in the form of a tuple |
| 146 | * |
| 147 | * @see tuffy.ground.KBMC#run() |
| 148 | */ |
| 149 | public Atom(Predicate p, Tuple at){ |
| 150 | assert(at.list.length == p.arity()); |
| 151 | pred = p; |
| 152 | args = at; |
| 153 | truth = null; |
| 154 | type = AtomType.NONE; |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * Returns this atom's human-friendly string representation. |
| 159 | */ |
| 160 | public String toString() { |
| 161 | ArrayList<String> as = new ArrayList<String>(); |
| 162 | for(int v : args.list) { |
| 163 | if(v >= 0){ |
| 164 | as.add("C" + v); |
| 165 | }else{ |
| 166 | as.add("v" + (-v)); |
| 167 | } |
| 168 | } |
| 169 | return pred.getName() + StringMan.commaListParen(as); |
| 170 | } |
| 171 | |
| 172 | } |