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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2026 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

Licensed 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.

heaps

This library defines a heap protocol and provides minimum and maximum heaps using two different implementations: pairing heaps and binary heaps.

The heap representations should be regarded as opaque terms, subjected to be changed without notice, and only accessed using the library predicates.

For backward-compatibility, the legacy.lgt file defines the heapp protocol extending the heap_protocol protocol plus the heap/1, minheap, and maxheap objects extending the binary_heap/1 object. These legacy protocol and objects are deprecated and should not be used in new code.

API documentation

Open the [../../apis/library_index.html#heaps](../../apis/library_index.html#heaps) link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

| ?- logtalk_load(heaps(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(heaps(tester)).

Usage

Choose the heap implementation that best suits your needs. The pairing heap implementation is usually the best choice, specially if insertion and merging operations dominate in your use case. You can easily benchmark and compare the two implementations using either a uses/2 directive with a parameter variable for the heap object and calling the heap predicates using implicit message-sending goals or a uses/1 directive defining an object alias for the heap object and using the alias with explicit message-sending goals.

The two main library objects are binary_heap(Order) and pairing_heap(Order), where Order is either < for a minimum heap or > for a maximum heap. For convenience, there are also binary_heap_min and pairing_heap_min objects for minimum heaps and binary_heap_max and pairing_heap_max objects for maximum heaps.

Credits

Original binary heap code by Richard O'Keefe and adapted to Logtalk by Paulo Moura and Victor Lagerkvist.