/** * Calculate the indexes for X[i] into a vector representing the enumeration * of the value assignments for the variables X and their corresponding * assignment in x. For example the Random Variables:<br> * Q::{true, false}, R::{'A', 'B','C'}, and T::{true, false}, would be * enumerated in a Vector as follows: * * <pre> * Index Q R T * ----- - - - * 00: true, A, true * 01: true, A, false * 02: true, B, true * 03: true, B, false * 04: true, C, true * 05: true, C, false * 06: false, A, true * 07: false, A, false * 08: false, B, true * 09: false, B, false * 10: false, C, true * 11: false, C, false * </pre> * * if X[i] = R and x = {..., R='C', ...} then the indexes returned would be * [4, 5, 10, 11]. * * @param X * a list of the Random Variables that would comprise the vector. * @param idx * the index into X for the Random Variable whose assignment we * wish to retrieve its indexes for. * @param x * an assignment for the Random Variables in X. * @return the indexes into a vector that would represent the enumeration of * the values for X[i] in x. */ public static int[] indexesOfValue(RandomVariable[] X, int idx, Map <RandomVariable, Object> x) { int csize = ProbUtil.expectedSizeOfCategoricalDistribution(X); FiniteDomain fd = (FiniteDomain)X[idx].getDomain(); int vdoffset = fd.getOffset(x.get(X[idx])); int vdosize = fd.size(); int[] indexes = new int[csize / vdosize]; int blocksize = csize; for (int i = 0; i < X.length; i++) { blocksize = blocksize / X[i].getDomain().size(); if (i == idx) { break; } } for (int i = 0; i < indexes.Length; i += blocksize) { int offset = ((i / blocksize) * vdosize * blocksize) + (blocksize * vdoffset); for (int b = 0; b < blocksize; b++) { indexes[i + b] = offset + b; } } return(indexes); }