Initial data commit

Task/QR-decomposition/Java/qr-decomposition-3.java

@@ -0,0 +1,30 @@
+import java.util.Locale;
+
+import org.apache.commons.math3.linear.Array2DRowRealMatrix;
+import org.apache.commons.math3.linear.QRDecomposition;
+import org.apache.commons.math3.linear.RealMatrix;
+
+public class Decompose {
+    public static void main(String[] args) {
+        var a = new Array2DRowRealMatrix(new double[][] {
+            {12, -51,   4},
+            { 6, 167, -68},
+            {-4,  24, -41}
+        });
+
+        var qr = new QRDecomposition(a);
+        print(qr.getQ());
+        System.out.println();
+        print(qr.getR());
+    }
+
+    public static void print(RealMatrix a) {
+        for (double[] u: a.getData()) {
+            System.out.print("[ ");
+            for (double x: u) {
+                System.out.printf(Locale.ROOT, "%10.4f ", x);
+            }
+            System.out.println("]");
+        }
+    }
+}