/*
 * Copyright (C) 2008-2015 by Holger Arndt
 * 
 * This file is part of the Universal Java Matrix Package (UJMP).
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership and licensing.
 *
 * UJMP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * UJMP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with UJMP; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

package org.ujmp.core.benchmark;

import java.math.BigDecimal;
import java.net.Inet4Address;
import java.util.Random;

import org.ujmp.core.Matrix;
import org.ujmp.core.doublematrix.DenseDoubleMatrix2D;
import org.ujmp.core.doublematrix.DoubleMatrix2D;
import org.ujmp.core.doublematrix.impl.DefaultDenseDoubleMatrix2D;
import org.ujmp.core.util.GCUtil;
import org.ujmp.core.util.MathUtil;

public abstract class BenchmarkUtil {

	public static String getResultDir(BenchmarkConfig config) {
		String name = config.getName();
		if (name == null) {
			return "results/" + getHostName() + "/" + System.getProperty("os.name") + "/Java"
					+ System.getProperty("java.version") + "/";
		} else {
			return "results/" + name + "/";
		}
	}

	public static String getHostName() {
		try {
			return Inet4Address.getLocalHost().getHostName();
		} catch (Exception e) {
			return "localhost";
		}
	}

	public static void rand(long benchmarkSeed, int run, int id, DoubleMatrix2D matrix) {
		Random random = new Random(benchmarkSeed + (run + 2) * 31 * 31 + (id + 1) * 31);
		int rows = (int) matrix.getRowCount();
		int cols = (int) matrix.getColumnCount();
		for (int r = 0; r < rows; r++) {
			for (int c = 0; c < cols; c++) {
				matrix.setDouble(random.nextDouble() - 0.5, r, c);
			}
		}
	}

	public static void randSymm(long benchmarkSeed, int run, int id, DoubleMatrix2D matrix) {
		Random random = new Random(benchmarkSeed + (run + 2) * 31 * 31 + (id + 1) * 31);
		int rows = (int) matrix.getRowCount();
		int cols = (int) matrix.getColumnCount();
		for (int r = 0; r < rows; r++) {
			for (int c = 0; c < cols && c <= r; c++) {
				double f = random.nextDouble() - 0.5;
				matrix.setDouble(f, r, c);
				matrix.setDouble(f, c, r);
			}
		}
	}

	public static void randPositiveDefinite(long benchmarkSeed, int run, int id, Matrix matrix) {
		Random random = new Random(benchmarkSeed + (run + 2) * 31 * 31 + (id + 1) * 31);
		DenseDoubleMatrix2D temp = new DefaultDenseDoubleMatrix2D(MathUtil.longToInt(matrix
				.getRowCount()), MathUtil.longToInt(matrix.getColumnCount()));
		int rows = (int) temp.getRowCount();
		int cols = (int) temp.getColumnCount();
		for (int r = 0; r < rows; r++) {
			for (int c = 0; c < cols; c++) {
				temp.setDouble(random.nextDouble(), r, c);
			}
		}
		DenseDoubleMatrix2D result = (DenseDoubleMatrix2D) temp.mtimes(temp.transpose());
		for (int r = 0; r < rows; r++) {
			for (int c = 0; c < cols; c++) {
				matrix.setAsDouble(result.getDouble(r, c), r, c);
			}
		}
	}

	public static DoubleMatrix2D createMatrix(Class matrixClass, long... size) {
		try {
			return (DoubleMatrix2D) matrixClass.getConstructor(long[].class).newInstance(size);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	public static DoubleMatrix2D createMatrix(Class matrixClass, Matrix source) {
		try {
			return (DoubleMatrix2D) matrixClass.getConstructor(Matrix.class).newInstance(source);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	public static double difference(Matrix m1, Matrix m2) {
		Matrix d = m1.minus(m2);
		// return normF(d).doubleValue();
		return d.normF();
	}

	public static BigDecimal normF(Matrix m) {
		long rows = m.getRowCount();
		long cols = m.getColumnCount();
		BigDecimal result = BigDecimal.ZERO;
		for (long ro = 0; ro < rows; ro++) {
			for (long c = 0; c < cols; c++) {
				BigDecimal b = m.getAsBigDecimal(ro, c);
				BigDecimal temp = BigDecimal.ZERO;
				if (MathUtil.isGreater(result.abs(), b.abs())) {
					temp = MathUtil.divide(b, result);
					temp = MathUtil.times(result.abs(), MathUtil.sqrt(MathUtil.plus(BigDecimal.ONE,
							MathUtil.times(temp, temp))));
				} else if (!MathUtil.equals(BigDecimal.ZERO, b)) {
					temp = MathUtil.divide(result, b);
					temp = MathUtil.times(b.abs(), MathUtil.sqrt(MathUtil.plus(BigDecimal.ONE,
							MathUtil.times(temp, temp))));
				} else {
					temp = BigDecimal.ZERO;
				}
				result = temp;
			}
		}
		return result;
	}

	public static void purgeMemory(BenchmarkConfig config) {
		if (config.isPurgeMemory()) {
			GCUtil.purgeMemory();
		} else if (config.isGCMemory()) {
			GCUtil.gc();
		}
	}

}