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/*
* 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 org.apache.commons.rng;
import java.util.stream.Stream;
/**
* Applies to generators that can be advanced a very large number of
* steps of the output sequence in a single operation.
*
* @since 1.3
*/
public interface LongJumpableUniformRandomProvider extends JumpableUniformRandomProvider {
/**
* Creates a copy of the JumpableUniformRandomProvider and then advances the
* state of the current instance. The copy is returned.
*
* The current state will be advanced in a single operation by the equivalent of a
* number of sequential calls to a method that updates the state of the provider. The
* size of the long jump is implementation dependent.
*
* Repeat invocations of this method will create a series of generators
* that are uniformly spaced at intervals of the output sequence. Each generator provides
* non-overlapping output for the length of the long jump for use in parallel computations.
*
* The returned copy may be jumped {@code m / n} times before overlap with the current
* instance where {@code m} is the long jump length and {@code n}
* is the jump length of the {@link #jump()} method.
*
* @return A copy of the current state.
*/
JumpableUniformRandomProvider longJump();
/**
* Returns an effectively unlimited stream of new random generators, each of which
* implements the {@link JumpableUniformRandomProvider} interface.
*
* @return a stream of random generators.
* @since 1.5
*/
default Stream longJumps() {
return Stream.generate(this::longJump).sequential();
}
/**
* Returns a stream producing the given {@code streamSize} number of new random
* generators, each of which implements the {@link JumpableUniformRandomProvider}
* interface.
*
* @param streamSize Number of objects to generate.
* @return a stream of random generators; the stream is limited to the given
* {@code streamSize}.
* @throws IllegalArgumentException if {@code streamSize} is negative.
* @since 1.5
*/
default Stream longJumps(long streamSize) {
UniformRandomProviderSupport.validateStreamSize(streamSize);
return longJumps().limit(streamSize);
}
}