MATLAB。

我正在尝试向量化一个循环，其中通过将对角矩阵中的每个单个元素与另一个 n×n 2D 矩阵中的列向量相乘来找到 2D 矩阵（n×n）的每个列向量。看起来矢量化很简单，但我一定遗漏了一些东西。我尝试先将对角矩阵转换为列向量，但它仍然需要一次执行一个元素的操作。

先感谢您。

%% example matrix
B = [ 3     2      .9    2
      2      4       1    2
      3      4      -1    0
     .5     .5      .1    1];

%% find eigenvectors and eigenvalues
 [ve, va] = eig(B,'nobalance');

%% get size of B ... 4
    [~,q]=size(B);

%% time constants
    t0=0;
    t = 2000e-6;

%% pre-allocate memory for Matrix Mn (Mnew) and Mp (Mprime)
    Mn=zeros(q,1);
    Mp=Mn;

%% Original code, runs correctly, not vectorized - steps through each column
for m = 1:q,
    Mn(:,m) = exp( va(m,m) * t0) * ve(:,m);             
    Mp(:,m) = exp( va(m,m) * t ) * ve(:,m);            
end

% quick explanation ^ for each column of Mn and Mp, a single value
% exp(va(i,i)*t) is multiplied by a column of ve(:,i)
% vectorizable?
% Mn(column) = A * ve(column), but A is an individual element in a different vector already

%% New code... vectorized?
% random starting idea:
va1 = va * [1; 1; 1; 1];  % changes diagonal matrix into column vector of values, BUT still has to calculate one at a time...