/**
* 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(IRandomVariable[] X, int idx, IMap <IRandomVariable, object> x)
{
int csize = ProbUtil.expectedSizeOfCategoricalDistribution(X);
IFiniteDomain fd = (IFiniteDomain)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);
}
