/*
 * Zorbage: an algebraic data hierarchy for use in numeric processing.
 *
 * Copyright (C) 2016-2020 Barry DeZonia
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package nom.bdezonia.zorbage.algorithm;

import nom.bdezonia.zorbage.algebra.Algebra;
import nom.bdezonia.zorbage.algebra.G;
import nom.bdezonia.zorbage.datasource.IndexedDataSource;
import nom.bdezonia.zorbage.storage.Storage;
import nom.bdezonia.zorbage.type.int64.SignedInt64Member;

/**
 * 
 * @author Barry DeZonia
 *
 */
public class SampleWithoutReplacement {

	private SampleWithoutReplacement() { }
	
	/**
	 * 
	 * @param algebra
	 * @param n
	 * @param a
	 * @param b
	 */
	public static <T extends Algebra<T,U>, U>
		void compute(T algebra, long n, IndexedDataSource<U> a, IndexedDataSource<U> b)
	{
		long aSize = a.size();
		long bSize = b.size();
		if (n > aSize)
			throw new IllegalArgumentException("cannot take "+n+" samples from "+aSize+" elements without replacement");
		if (n > bSize)
			throw new IllegalArgumentException("cannot fit "+n+" samples in "+bSize+" spaces");
		SignedInt64Member idx = G.INT64.construct();
		IndexedDataSource<SignedInt64Member> indices = Storage.allocate(n, idx);
		for (long i = 0; i < n; i++) {
			idx.setV(i);
			indices.set(i, idx);
		}
		Shuffle.compute(G.INT64, indices);
		U tmp = algebra.construct();
		for (long i = 0; i < n; i++) {
			indices.get(i, idx);
			a.get(idx.v(), tmp);
			b.set(i, tmp);
		}
	}
}

/*
 * Zorbage: an algebraic data hierarchy for use in numeric processing.
 *
 * Copyright (C) 2016-2020 Barry DeZonia
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package nom.bdezonia.zorbage.algorithm;

import nom.bdezonia.zorbage.algebra.Algebra;
import nom.bdezonia.zorbage.algebra.G;
import nom.bdezonia.zorbage.datasource.IndexedDataSource;
import nom.bdezonia.zorbage.storage.Storage;
import nom.bdezonia.zorbage.type.int64.SignedInt64Member;

/**
 * 
 * @author Barry DeZonia
 *
 */
public class SampleWithoutReplacement {

	private SampleWithoutReplacement() { }
	
	/**
	 * 
	 * @param algebra
	 * @param n
	 * @param a
	 * @param b
	 */
	public static <T extends Algebra<T,U>, U>
		void compute(T algebra, long n, IndexedDataSource<U> a, IndexedDataSource<U> b)
	{
		long aSize = a.size();
		long bSize = b.size();
		if (n > aSize)
			throw new IllegalArgumentException("cannot take "+n+" samples from "+aSize+" elements without replacement");
		if (n > bSize)
			throw new IllegalArgumentException("cannot fit "+n+" samples in "+bSize+" spaces");
		SignedInt64Member idx = G.INT64.construct();
		IndexedDataSource<SignedInt64Member> indices = Storage.allocate(aSize, idx);
		for (long i = 0; i < n; i++) {
			idx.setV(i);
			indices.set(i, idx);
		}
		Shuffle.compute(G.INT64, indices);
		U tmp = algebra.construct();
		for (long i = 0; i < n; i++) {
			indices.get(i, idx);
			a.get(idx.v(), tmp);
			b.set(i, tmp);
		}
	}
}

Fix a bug in one of the sampling algorithms