怎么用MATLAB实现argmin函数？

function x = Corresponding_index(A,B)

% Function: Determine the position of the element in array B corresponding to the equivalent element in array A

% Author：Gong Pf. Time:2019-7-2

% Remark: Only consider A and B is one or two dimension

% And x is a size(B,1)*size(B,2) cell

% Each cell x{i,j} is a t*2 array

% (t is the number of times that the element B(i,j) appears in A)

% And x{i,j}(n,1),x{i,j}(n,2) represent the row and column of the element in A

% Example1:A = [1 2 3 4 1 2 8]

% B = [0 1 2]

% x = argmax_min(A,B)

% x = [][2x2 double][2x2 double] = [] [1 11 5] [1 21 6]

% Example2:A = [1 2 42 4 25 9 83 9 3]

% B = [1 32 9]

% x = argmax_min(A,B)

% x = [1x2 double][2x2 double]= [1 1][4 14 3]

% [3x2 double][2x2 double] [1 22 12 3] [3 24 2]

% Interpret the result: (x{1,1}(1,1),x{1,1}(1,2))=(1,1)

%This is where B(1,1) appears in A

% (x{1,2}(1,1),x{1,2}(1,2))=(4,1) and (x{1,2}(2,1),x{1,2}(2,2))=(4,3)

% These are where B(1,2) appears in A

% Can be used to implement argmin and argmax functions

%% A and B array is less or equal two-dimensional

row_col = size(A)

ii = 1

jj = 1

% Count the number of occurrences of elements in one-dimensional array B in A

B_times = zeros(size(B))

for i = 1:size(B,1)

for j = 1:size(B,2)

B_times(i,j) = length(find(A == B(i,j)))

end

end

% Count the position of the element in B in A

for i = 1:size(B,1)

for j = 1:size(B,2)

for m = 1:row_col(1)

for n = 1:row_col(2)

if A(m,n) == B(i,j)

x{i,j}(1,ii) = m

x{i,j}(2,jj) = n

ii = ii + 1

jj = jj + 1

end

end

end

ii = 1

jj = 1

end

end

x=norm(y-ah,2)

x1=min(min(x))

x2=Corresponding_index(x,x1)

disp(x2)

y=λ*norm(h,1)

题主的matlab中的argmin函数可以这样来表示求解：

1、自定义函数为目标函数，即

function y=argmin_fun(x)

xt=。。。

yt=。。。

zt=。。。

a=x(1)b=x(2)c=x(3)

y=(xt-a)^2+(yt-b)^2+(zt-c)^2-9.8^2

end

2、确定a、b、c的初值， 如x0=[0,0,0]，根据问题而定

3、确定a、b、c的上限lb和下限ub

4、使用fmincon函数求出a、b、c的值，及其极值

[x,fval] = fmincon(@(x) argmin_fun(x),x0,[],[],[],[],lb,ub)

a=x(1)，b=x(2)，c=x(3) %系数

fmin=fval %最小值

---