content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package accord.utils;
  
  public interface IndexedRangeFoldToLong
  {
      /**
       * Apply some long->long merge function accepting a constant parameter p1 and the prior output of this
       * function or an initial value, to some range of indexes referencing some other indexed collection.
       *
       * This function is used for folding over a filtered collection, where contiguous ranges are expected
       * and can be handled batch-wise.
       */
      long apply(long p1, long accumulator, int fromIndex, int toIndex);
  }