MATLAB: Shifting without for loop

regression shift nofor

Hello,
I have two cells each 60×23 and each cell consist of columns with different length.
For each cell, I need
1- Get ten values starting from last values,
2- Apply fitlm function on the obtained values
3- Get the Coefficients {2,1} of the fitlm
4- omit the last value in step1, shift one value and get ten elements. Then repeat steps 2and3. (hopefully without for loops as i found it complicated with cells having variable lengths).
5- Goal: obtain a 60×23 cell where each cell has the Coefficients of linear regression for each ten values.
My attempted solution works till step 3 as shown:
Time2sec = lst2val         % 60x23 cell

delta2sec = delta.delta    % 60x23 cell
len0 = cellfun(@length, Time2sec, 'uni',0)
len1 = cellfun (@(x) x-9, len0, 'uni',0)
%len1 = cellfun (@(x) x-10, len0,'uni',0)
len2 = cellfun (@(x) x+9, len1, 'uni',0)
last10frames = cellfun (@(x,y1, y2) x( y1:y2 ), Time2sec, len1, len2  , 'Uni',0)
len00 = cellfun(@length, delta2sec, 'uni',0)
len11 = cellfun (@(x) x-9, len00,'uni',0)
len22 = cellfun (@(x) x+9, len11, 'uni',0)
last10frames_2 = cellfun (@(x,y1, y2) x( y1:y2 ), delta2sec, len11, len22  , 'Uni',0)
reg0 = cellfun (@fitlm, last10frames, last10frames2, 'uni',0)
M_value =  cellfun (@(x) x.Coefficients{2,1}, reg0 , 'uni', 0) 
% omit value, shift with step -1 till first element in each cell and apply linear regression.
I really appreciat the help.

Best Answer

If the vectors in the corresponding cell arrays are equal in length, then this straightforward code should work:
M = 60;
N = 23;
MIN_VEC_SIZE = 10;
MAX_VEC_SIZE = 30;
% Make up some data
rng default
Time2sec  = cell(M,N);
delta2sec = cell(M,N);
M_value   = cell(M,N);
Time2sec = cellfun(@(x)randn(max(MIN_VEC_SIZE,randi(MAX_VEC_SIZE)),1),Time2sec,'uni',false);
delta2sec = cellfun(@(x)randn(size(x)),Time2sec,'uni',false);
% Calculate the regressions
for ii = 1:M
for jj = 1:N
    numberRegressionsThisCell = numel(Time2sec{ii,jj})-9;
    M_value{ii,jj} = zeros(numberRegressionsThisCell,1);
    for nr = 1:numberRegressionsThisCell
        mdl = fitlm(Time2sec{ii,jj}(nr:nr+9),delta2sec{ii,jj}(nr:nr+9));
        M_value{ii,jj}(nr) = mdl.Coefficients{2,1};
    end
end
end
(If not, this code could be easily modified to accommodate that.)
The vast majority of the execution time is spent doing the regressions, so there will likely be little advantage in excising the for loops.
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