examp2_30.m

来自「matlab的大量实例代码」· M 代码 · 共 34 行

tic,
for i=1:10000 % 大循环在外层
   for j=1:5
      H(i,j)=1/(i+j-1);
   end
end
toc

tic
for j=1:5     % 大循环在内层
   for i=1:10000
      H1(i,j)=1/(i+j-1);
   end
end
toc

tic
H=zeros(10000,5); % 大矩阵预定维
for j=1:5
   for i=1:10000
      H(i,j)=1/(i+j-1);
   end
end
toc

tic
H=zeros(10000,5);
for i=1:5
   H(:,i)=1./[i:i+9999]';
end
toc

tic, [i,j]=meshgrid(1:10000,1:5); H=1./(i+j-1); toc