Obtaining a scalar value from a vector output

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Sergio 2024-4-4，15:43

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https://ww2.mathworks.cn/matlabcentral/answers/2102986-obtaining-a-scalar-value-from-a-vector-output

评论： Voss 2024-4-4，17:01

Hi, with the given files, if you run test-modified.m and then enzymeLeastSquares.m, you obtain the necessary inputs for running

enzymeGeneral.m

So when running finally enzymeGeneral.m, it outputs F and G.

However, the output from enzymeGeneral.m should be the scalar value of the objective F and the corresponding 2x1 gradient G.

The first I get by doing

F=norm((1/2)*(sum(y0_all)).^2)

which gives the scalar value of F. However, the correspondikng 2x1 gradient G is not returned. What is the right command? Do anyone have a link to a MATLAB page that shows the relevant command?

Thanks

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采纳的回答

Voss 2024-4-4，15:56

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https://ww2.mathworks.cn/matlabcentral/answers/2102986-obtaining-a-scalar-value-from-a-vector-output#answer_1436616

编辑：Voss 2024-4-4，15:57

在 MATLAB Online 中打开

enzymeGeneral.m

% take a look at what enzymeGeneral.m is
type enzymeGeneral.m
function [result,grad_all] = enzymeGeneral(k)
N = 4; % number of experiments
result = zeros(2*N,1); % pre-allocate result arrays
grad_all = zeros(2*N,2);
dt=0.01;
T=1;
%k=[5;1];
y0_all = [2 1 1 4; 1 1 0 1];
y1_all = [1.0 0.5 0.3 2.4; 2.1 1.6 0.9 2.7];
for ii = 1:N
    y0 = y0_all(:,ii);
    y1 = y1_all(:,ii);
    [SP,grad]=enzyme(y0,k,dt,T);
    result((ii-1)*2+[1 2]) = y1-SP;
    grad_all((ii-1)*2+[1 2],:) = -grad;
end
F = (1/2)*(sum(y0_all)).^2
G =  (sum(y0_all)).*(y1_all).*(y0_all)