创建hilbert矩阵.txt

控制流语句if-else-end

（1）Hilbert矩阵 。
（2）
K=5;
A = zeros(K,K) ;					
for m = 1:K						
	for n = 1:K					
		A(m,n) = 1/(m+n -1);
	end
end
format rat
A
format short g  
A =
       1              1/2            1/3            1/4            1/5     
       1/2            1/3            1/4            1/5            1/6     
       1/3            1/4            1/5            1/6            1/7     
       1/4            1/5            1/6            1/7            1/8     
       1/5            1/6            1/7            1/8            1/9       

（3）
clear
tic								
K=1000;
for m = 1:K
	for n = 1:K
		A1(m,n) = 1/(m+n -1);
	end
end
t1=toc							 
t1 =
       17.434  

tic
K=1000;
A2 = zeros(K,K);				
for m = 1:K
	for n = 1:K
		A2(m,n) = 1/(m+n -1);
	end
end
t2=toc  
t2 =
       2.1895  

（4）
tic
N=1000;
n=repmat(1:N,N,1);
m=n';
A3=1./(n+m-1);
t3=toc  
t3 =
      0.13909