Recursively fill array in MATLAB

Question

I am trying to fill an array I Using a recursive formula. The formula is shown below.

In this formula I already computed the B array and I know all the elements and M is the dimension of B array which is equal to dimension of I array. u,v and w letters indicate indices. My function is:

function I_matrix = fill_I_recursively(B_matrix, u_ind, v_ind, w_ind)
M = size(B_matrix,1);
if u_ind == 1 && v_ind == 1 && w_ind == 1
    I_matrix(u_ind,v_ind,w_ind) = 0; 
else
    if w_ind > 1
        I_matrix(u_ind,v_ind,w_ind) = fill_I_recursively(B_matrix, u_ind, v_ind, w_ind-1) + B_matrix(u_ind,v_ind,w_ind-1);
    elseif v_ind > 1
        I_matrix(u_ind,v_ind,w_ind) = fill_I_recursively(B_matrix, u_ind, v_ind-1, M-1) + B_matrix(u_ind,v_ind-1,M-1);
    else
        I_matrix(u_ind,v_ind,w_ind) = fill_I_recursively(B_matrix, u_ind-1,  M-1, M-1) + B_matrix(u_ind-1,M-1,M-1);
   end
end

I call this function in my program:

I_matrix = NaN(max_boxes,max_boxes,max_boxes);
%%fill the I matrix using recursive function
for u_ind = 1:max_boxes
    for v_ind = 1:max_boxes
        for w_ind = 1:max_boxes
            I_matrix(u_ind,v_ind,w_ind) = fill_I_recursively(B_matrix, u_ind, v_ind, w_ind);
        end
    end
end

When it runs I get the error message "Assignment has more non-singleton rhs dimensions than non-singleton subscripts". Could you please help me to solve this problem?

Answer 1

由于对您的fill_I_recursively函数的期望不同而出现问题。

在函数定义中，输出为I_matrix，它是一个多维数组。

在您的主程序中，fill_I_recursively的预期输出是标量，它被填充到I_matrix多维数组的条目中。

您应该更改两个部分之一，以使它们保持一致。

这是一个如何修改函数定义以输出标量的示例：

function I_uvw = fill_I_recursively(B_matrix, u_ind, v_ind, w_ind)
M = size(B_matrix,1);
if u_ind == 1 && v_ind == 1 && w_ind == 1
    I_uvw = 0; 
else
    if w_ind > 1
        I_uvw = fill_I_recursively(B_matrix, u_ind, v_ind, w_ind-1) + B_matrix(u_ind,v_ind,w_ind-1);
    elseif v_ind > 1
        I_uvw = fill_I_recursively(B_matrix, u_ind, v_ind-1, M-1) + B_matrix(u_ind,v_ind-1,M-1);
    else
        I_uvw = fill_I_recursively(B_matrix, u_ind-1,  M-1, M-1) + B_matrix(u_ind-1,M-1,M-1);
   end
end