Pretty print matrix.

Author: jingedawang

src/utils/MatrixPrinter.java

@@ -1,27 +1,50 @@
 /**
- * Copyright 2020 jingedawang
+ * Copyright 2022 jingedawang
  */
 package utils;
 
 import matrix.Matrix;
 
 /**
- * <h3>Matrix printer</h3>
+ * Matrix printer.
  */
 public class MatrixPrinter {
 
 	/**
 	 * Print the matrix in a readable format.
 	 *
-	 * @param m The matrix to be printed.
+	 * @param matrix The matrix to be printed.
 	 */
-	public static void print(Matrix m) {
-		System.out.print("[");
-		for (int i = 0; i < m.rows(); i++) {
-			for (int j = 0; j < m.columns() - 1; j++) {
-				System.out.print(m.value()[i][j] + ",");
+	public static <T extends Number> void print(Matrix<T> matrix) {
+		double maxValue = MatrixUtils.max(matrix).doubleValue();
+		double minValue = MatrixUtils.min(matrix).doubleValue();
+		double maxAbsValue = Math.max(Math.abs(maxValue), Math.abs(minValue));
+		int digitNumberBeforePoint = String.format("%.0f", maxAbsValue).length();
+
+		for (int i = 0; i < matrix.rows(); i++) {
+			if (i == 0) {
+				System.out.print('[');
+			}
+			else {
+				System.out.print(' ');
+			}
+			for (int j = 0; j < matrix.columns(); j++) {
+				if (matrix.get(i, j) instanceof Integer) {
+					System.out.printf("%" + digitNumberBeforePoint + "d", matrix.get(i, j));
+				}
+				else {
+					System.out.printf("%" + (digitNumberBeforePoint + 3) + ".2f", matrix.get(i, j));
+				}
+				if (j != matrix.columns() - 1) {
+					System.out.print(", ");
+				}
+			}
+			if (i != matrix.rows() - 1) {
+				System.out.println();
+			}
+			else {
+				System.out.println(']');
 			}
-			System.out.println(m.value()[i][m.columns() - 1] + (i == m.rows() - 1 ? "]" : ""));
 		}
 	}
 

src/utils/MatrixUtils.java

@@ -0,0 +1,69 @@
+/**
+ * Copyright 2022 jingedawang
+ */
+package utils;
+
+import matrix.Matrix;
+
+/**
+ * Utility class for {@link Matrix}.
+ */
+public class MatrixUtils {
+
+	/**
+	 * Get the maximum value in the matrix.
+	 *
+	 * @param matrix The matrix object.
+	 * @param <T> The type of the underlying elements of the matrix.
+	 * @return The maximum value in the matrix.
+	 */
+	public static <T extends Number> T max(Matrix<T> matrix) {
+		Number max;
+		if (matrix.get(0, 0) instanceof Integer) {
+			max = Integer.MIN_VALUE;
+		}
+		else {
+			max = Double.MIN_VALUE;
+		}
+		for (int i = 0; i < matrix.rows(); i++) {
+			for (int j = 0; j < matrix.columns(); j++) {
+				if (matrix.get(0, 0) instanceof Integer) {
+					max = Math.max((Integer) max, (Integer) matrix.get(i, j));
+				}
+				else {
+					max = Math.max((Double) max, (Double) matrix.get(i, j));
+				}
+			}
+		}
+		return (T) max;
+	}
+
+	/**
+	 * Get the minimum value in the matrix.
+	 *
+	 * @param matrix The matrix object.
+	 * @param <T> The type of the underlying elements of the matrix.
+	 * @return The minimum value in the matrix.
+	 */
+	public static <T extends Number> T min(Matrix<T> matrix) {
+		Number min;
+		if (matrix.get(0, 0) instanceof Integer) {
+			min = Integer.MAX_VALUE;
+		}
+		else {
+			min = Double.MAX_VALUE;
+		}
+		for (int i = 0; i < matrix.rows(); i++) {
+			for (int j = 0; j < matrix.columns(); j++) {
+				if (matrix.get(0, 0) instanceof Integer) {
+					min = Math.min((Integer) min, (Integer) matrix.get(i, j));
+				}
+				else {
+					min = Math.min((Double) min, (Double) matrix.get(i, j));
+				}
+			}
+		}
+		return (T) min;
+	}
+
+}

test/MatrixPrinterTest.java

@@ -14,8 +14,11 @@ public class MatrixPrinterTest {
 
 	@Test
 	void print() {
-		Matrix<Double> matrix = MatrixGenerator.generateRandomDoubleMatrix(4, 5);
-		MatrixPrinter.print(matrix);
+		Matrix<Integer> integerMatrix = MatrixGenerator.generateRandomIntegerMatrix(4, 5, 50);
+		MatrixPrinter.print(integerMatrix);
+
+		Matrix<Double> doubleMatrix = MatrixGenerator.generateRandomDoubleMatrix(4, 5, 100);
+		MatrixPrinter.print(doubleMatrix);
 	}
 
 }