矩阵的输入问题
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Text.RegularExpressions;
namespace 矩阵输入
{
  public class Class2
  {
  public static double[,] jz;
  public double[,] SR(string richTextBox)
  {
   
  string tetmsg = richTextBox;
  string[] strSum = tetmsg.Replace("\r\n", "@").Split('@');
  int m = 0, n = 0;
  int j = strSum.Length;
  foreach (string g in strSum)
  {
  string[] h = Regex.Split(g, " ", RegexOptions.IgnoreCase);
  int i = h.Length;
   
  foreach (string l in h)
  {
  jz[m,n] = double.Parse(l);
  n++;
  }
  m++;
   
  } 
  return jz;
  }
  }
}
运行时，显示错误在这个里面，错误是“未将对象引用设置到对象的实例。”望哪位大神帮帮忙，帮改一下