/// <summary>
 /// Visits (and possibly alters) some entries of this vector in default order
 /// (increasing index).
 /// </summary>
 /// <param name="visitor">visitor to be used to process the entries of this vector</param>
 /// <param name="start">the index of the first entry to be visited</param>
 /// <param name="end">the index of the last entry to be visited (inclusive)</param>
 /// <returns>the value returned by <see cref="FieldVectorChangingVisitor.end()"/>
 /// at the end of the walk</returns>
 /// <exception cref="NumberIsTooSmallException"> if <c>end < start</c>.</exception>
 /// <exception cref="OutOfRangeException"> if the indices are not valid.</exception>
 public T walkInDefaultOrder(FieldVectorChangingVisitor <T> visitor, int start, int end)
 {
     checkIndices(start, end);
     visitor.start(getDimension(), start, end);
     for (int i = start; i <= end; i++)
     {
         setEntry(i, visitor.visit(i, getEntry(i)));
     }
     return(visitor.end());
 }
        /// <summary>
        /// Visits (and possibly alters) all entries of this vector in default order
        /// (increasing index).
        /// </summary>
        /// <param name="visitor">the visitor to be used to process and modify the entries
        /// of this vector</param>
        /// <returns>the value returned by <see cref="FieldVectorChangingVisitor.end()"/>
        /// at the end of the walk</returns>
        public T walkInDefaultOrder(FieldVectorChangingVisitor <T> visitor)
        {
            int dim = getDimension();

            visitor.start(dim, 0, dim - 1);
            for (int i = 0; i < dim; i++)
            {
                setEntry(i, visitor.visit(i, getEntry(i)));
            }
            return(visitor.end());
        }