Cellfun or for loop

Question

Atreyu91 2015-8-26

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/236485-cellfun-or-for-loop

回答： Guillaume 2015-8-26

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

I have the following code where I am trying to obtain U for every k value and the values in a cell array:

G = 1x3 cell

If

G{1,1} = [-6.45230249676815e-06;
           2.43528862745912e-20;
           2.00553181084869e-19;
           6.45309629402509e-06;
           -9.16814514353228e-20;
           6.45627245974903e-06]
G{1,2} = [-3.22654814674929e-06;
     -5.38986674121538e-20;
     -2.25622328702039e-20;
     3.22734209049890e-06;
     -2.25622301386590e-20;
      3.23051981960359e-06]
G{1,3} = [-2.15129672917826e-06;
        -2.05328256780239e-20;
        -6.68510603470547e-21;
        2.15209081944770e-06;
       -6.68510421367576e-21;
        2.15527011276720e-06]

and

k = 0.0012
k = 0.0025
k = 0.0037
L1 = 0.1
L2= 0.2
L3 = 0.4
U1 = G(1)*exp(-k*L1)+G(2)*exp(-k*L1);
U2 = G(3)*exp(-k*L1)+G(4)*exp(-k*L1);
U3 = G(5)*exp(-k*L1)+G(6)*exp(-k*L1);

I need to obtain U1,U2,U3 for each value of k

I have tried using for loops and cellfun() etc.

U1 = cellfun(@(G, k) G(1)*exp(-k*L1)+G(2)*exp(-k*L1), G, k, 'UniformOutput', 0);

but it keeps saying "Error using cellfun Input #3 expected to be a cell array, was double instead."

Can anyone please show me how to perform this in MATLAB?

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Answer 1

Walter Roberson 2015-8-26

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/236485-cellfun-or-for-loop#answer_190377

在 MATLAB Online 中打开

Your description is unclear. One interpretation is that you want

   nG = length(G);
   kvals = [0.0012 0.0025 0.0037];
   nk = length(kvals);
   L = [0.1 0.2 0.4];
   U = zeros(nk, nG);
   for Gidx = 1 : nG
     g = G{Gidx};
     for kidx = 1 : nk
       k = kvals(kidx);
       U(kidx, Gidx) = g(2*kidx-1)*exp(-k*L(kidx)+g(2*kidx)*exp(-k*L(kidx));
     end
   end

but another possibility is that you want all combinations of L used with all combinations of k rather than corresponding L used with each k.

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Atreyu91 2015-8-26

Ah yes, it is meant to be L1 in U1 L2 in U2 And L3 in U3 Thought I fixed that

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Answer 2

Guillaume 2015-8-26

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/236485-cellfun-or-for-loop#answer_190393

在 MATLAB Online 中打开

k = 0.0012
k = 0.0025
k = 0.0037

One would assume that's not what you've entered in matlab (since that would result in just k = 0.0037) but something else. For your cellfun to work, you'd have to have written k as a cell array:

k = {0.0012; 0.0025; 0.0037};

The error is clear your third input (k) is not a cell array.