package ie.dcu.array;

/**
 * A reduce operation.
 * 
 * @author Kevin McGuinness
 */
public interface Reduction<T, U> {

	/**
	 * Perform a reduction.
	 * 
	 * @param accumulator 
	 *        The accumulated value so far.
	 * @param value
	 *        The next value in the array.
	 * @param index
	 *        The index of the value in the array.
	 * @return
	 *        The result of the reduction.
	 */
	public U reduce(U accumulator, T value, int index);
	
	
	/**
	 * A long width reduction.
	 */
	public interface Long {
		
		/**
		 * Perform a reduction.
		 * 
		 * @param accumulator 
		 *        The accumulated value so far.
		 * @param value
		 *        The next value in the array.
		 * @param index
		 *        The index of the value in the array.
		 * @return
		 *        The result of the reduction.
		 */
		public long reduce(long accumulator, long value, int index);
	}
	
	/**
	 * A double precision reduction.
	 */
	public interface Double {
		
		/**
		 * Perform a reduction.
		 * 
		 * @param accumulator 
		 *        The accumulated value so far.
		 * @param value
		 *        The next value in the array.
		 * @param index
		 *        The index of the value in the array.
		 * @return
		 *        The result of the reduction.
		 */
		public long reduce(double accumulator, double value, int index);
	}
}