From 62069dab1655a7e0d3216632afe0be0b8a91a8e3 Mon Sep 17 00:00:00 2001
From: jlizier <joseph.lizier@gmail.com>
Date: Thu, 23 Mar 2017 14:31:38 +1100
Subject: [PATCH] Added several utilities for selecting columns to MatrixUtils

---
 .../infodynamics/utils/MatrixUtils.java       | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/java/source/infodynamics/utils/MatrixUtils.java b/java/source/infodynamics/utils/MatrixUtils.java
index 7203b7a..8c5b799 100755
--- a/java/source/infodynamics/utils/MatrixUtils.java
+++ b/java/source/infodynamics/utils/MatrixUtils.java
@@ -1299,6 +1299,14 @@ public class MatrixUtils {
 		return returnData;
 	}
 
+	public static boolean[] selectColumn(boolean matrix[][], int columnNo) {
+		boolean[] column = new boolean[matrix.length];
+		for (int r = 0; r < matrix.length; r++) {
+			column[r] = matrix[r][columnNo];
+		}
+		return column;
+	}
+	
 	public static int[] selectColumn(int matrix[][], int columnNo) {
 		int[] column = new int[matrix.length];
 		for (int r = 0; r < matrix.length; r++) {
@@ -1342,6 +1350,25 @@ public class MatrixUtils {
 		return column;
 	}
 
+	/**
+	 * Extract the required columns from the matrix
+	 * 
+	 * @param matrix
+	 * @param fromCol
+	 * @param cols
+	 * @return
+	 */
+	public static double[][] selectColumns(double matrix[][], 
+			int fromCol, int cols) {
+		double[][] data = new double[matrix.length][cols];
+		for (int r = 0; r < matrix.length; r++) {
+			for (int cIndex = 0; cIndex < cols; cIndex++) {
+				data[r][cIndex] = matrix[r][cIndex + fromCol];
+			}
+		}
+		return data;
+	}
+
 	/**
 	 * Extract the required columns from the matrix
 	 * 
@@ -1435,6 +1462,27 @@ public class MatrixUtils {
 		return data;
 	}
 
+	/**
+	 * Extract the required rows and columns from the matrix
+	 * 
+	 * @param matrix 2D data array
+	 * @param fromRow index of the first row to return
+	 * @param rows number of rows (including the first) to return
+	 * @param fromCol index of the first column to return
+	 * @param cols number of columns (including the first) to return
+	 * @return a 2D data array of the selected rows and columns
+	 */
+	public static double[][] selectRowsAndColumns(double matrix[][],
+			int fromRow, int rows, int fromCol, int cols) {
+		double[][] data = new double[rows][cols];
+		for (int rIndex = 0; rIndex < rows; rIndex++) {
+			for (int cIndex = 0; cIndex < cols; cIndex++) {
+				data[rIndex][cIndex] = matrix[rIndex + fromRow][cIndex + fromCol];				
+			}
+		}
+		return data;
+	}
+
 	public static double[][] selectFirstTwoDimenions(double[][][][] matrix, int d2, int d3) {
 		double[][] newMatrix = new double[matrix.length][];
 		for (int i = 0; i < matrix.length; i++) {