SparseTensor.java 文件源码

/**
 * Construct a sparse tensor with indices and values
 * 
 * @param dims
 *            dimensions of a tensor
 * @param nds
 *            n-dimensional keys
 * @param vals
 *            entry values
 */
@SuppressWarnings("unchecked")
public SparseTensor(int[] dims, List<Integer>[] nds, List<Double> vals) {
    if (dims.length < 3)
        throw new Error("The dimension of a tensor cannot be smaller than 3!");

    numDimensions = dims.length;
    dimensions = new int[numDimensions];

    ndKeys = (List<Integer>[]) new List<?>[numDimensions];
    keyIndices = (Multimap<Integer, Integer>[]) new Multimap<?, ?>[numDimensions];

    for (int d = 0; d < numDimensions; d++) {
        dimensions[d] = dims[d];
        ndKeys[d] = nds == null ? new ArrayList<Integer>() : new ArrayList<Integer>(nds[d]);
        keyIndices[d] = HashMultimap.create();
    }

    values = vals == null ? new ArrayList<Double>() : new ArrayList<>(vals);
    indexedDimensions = new ArrayList<>(numDimensions);
}