Question

我有一个矩阵A=(1 2; 3 4)，我想将A增加到B = (1 2 0; 3 4 0; 0 0 0)，我该怎么办？

一种方法是：B = [[A, zeros(2,1)]; zeros(1,3)]

但是在动态过程中，任何其他想法都可能是笨拙的？

Answer 1

B=A
B(3,3)=0

Matlab使用零自动填充其他元素

Answer 2

此外：

// Allow short name access to java.awt.Color
import java.awt.Color;

/*
 * This is the shell for assignment: MyScene.
 * This program draws a simple scene using additional
 * classes that the student creates.
 * 
 * @author Dan Jinguji
 * @author Chris Wilson
 * @version Assignment 4: MyScene
 */
public class MyScene extends NscWindow {

   // instance variables
   private MyHouse house1;
   private MyHouse house2;
   private MyHouse house3;
   private MyTree tree1;
   private MyTree tree2;
   private MyTree tree3;

  /**
   * Constructor for objects of class MyScene
   */
  public MyScene() {
    // Specify the constructor for the superclass
    super(10, 10, 400, 300);
    // set characteristics for the object
    setTitle("My Scene");

    // Draw the sky
    getContentPane().setBackground(new Color(0x00, 0xCC, 0xFF));

    // Draw some grass
    NscRectangle grass = new NscRectangle(0, 100, 400, 200);
    grass.setBackground(new Color(0x00, 0x99, 0x00));
    grass.setFilled(true);
    add(grass);

    // instantiate new house objects
    house1 = new MyHouse(100, 50, Color.white);
    add(house1);    
    house2 = new MyHouse(200, 150);
    add(house2);    
    house3 = new MyHouse(0, 200, Color.orange);
    add(house3);    
    // request a rerendering of the window
    repaint();

    // instantiate new tree objects
    tree1 = new MyTree(35, 20, Color.white);
    add(tree1);
    tree2 = new MyTree(290, 50);
    add(tree2);
    tree3 = new MyTree(5, 60, Color.cyan);
    add(tree3);
    // request a rerender
    repaint();

  } 

  /**
   * Alter the scene, by changing color
   */
  public void change1() {
    // change the color of the houses and trees
    house1.setColor(Color.red);
    tree1.setColor(Color.black);    
    house2.setColor(Color.magenta);
    tree2.setColor(Color.orange);    
    house3.setColor(Color.black);
    tree3.setColor(Color.pink);
    // request a rerendering of the window
    repaint();
  }

   /**
    * Alter the scene, by changing location
    */
  public void change2() {
    // change the location of the houses and trees
    house1.setLocation(50, 125);    
    house2.setLocation(150, 25);    
    house3.setLocation(0, 150);
    tree1.setLocation(25, 10);
    tree2.setLocation(300, 20);
    tree3.setLocation(150, 90);
    // request a rerendering of the window
    repaint();
  }

   /**
    * Alter the scene, by changing size of objects and underlying containers   
    * 
    */
  public void change3() {
    house1.setSize(80, 60);
  } 



   /**
    * Alter the scene, restoring original settings
    */
  public void reset() {
    // reset the initial values for the house
    house1.setLocation(100, 50);
    house1.setColor(Color.white);
    house1.setSize(120, 90);    
    // reset the initial values for the house
    house2.setLocation(200, 150);
    house2.setColor(Color.blue);
    house2.setSize(120, 90);    
    // reset the initial values for the house
    house3.setLocation(0, 200);
    house3.setColor(Color.orange);
    house3.setSize(120, 90);
    // rest the initial values for the tree
    tree1.setLocation(35, 20);
    tree1.setColor(Color.white);
    tree1.setSize(60, 120);
    // rest the initial values for the tree
    tree2.setLocation(290, 50);
    tree2.setColor(Color.green);
    tree2.setSize(60, 120);
    // rest the initial values for the tree
    tree3.setLocation(5, 90);
    tree3.setColor(Color.cyan);
    tree3.setSize(60, 120);
    // request a rerendering of the window
    repaint();
  }

   /**
    * The application method, to test your code
    *
    * @param args The command-line arguments
    */
  public static void main(String[] args) {

    // declare a MyScene reference
    MyScene aScene;
    // instantiate MyScene
    aScene = new MyScene();
    // pause
    javax.swing.JOptionPane.showMessageDialog(null, "Press OK to continue");

    // test setColor
    aScene.change1();
    javax.swing.JOptionPane.showMessageDialog(null, "Press OK to continue");

    // test setLocation
    aScene.change2();
    javax.swing.JOptionPane.showMessageDialog(null, "Press OK to continue");

    // test setSize
    aScene.change3();
    javax.swing.JOptionPane.showMessageDialog(null, "Press OK to continue");    


    // reset initial values
    aScene.reset();
  }

}

输出：

padarray(A,[1 1],'post')

它更加通用，使语义非常清晰。

在matlab中，如何增加矩阵的维数？

2 个答案: