How to export a cell array consisting of matrices in each cell into different excel sheets in single workbook?

So this is a function which saves transformation matrices, stiffness matrices into cell arrays. Now I want these matrices present in each cell of their respective cell arrays to get exported into an excel sheet. How do I do it? when i use xlswrite the excel sheet is produced but shows different size matrices with different values though some of the element values in matrices are correct but entirely wrong.

function [T,k,K,Kstr]=memdetails(E,A,nodes,mem,tdof,dof)
    T=cell(1,length(mem));
    k=cell(1,length(mem));
    K=cell(1,length(mem));
    Kstr=zeros(dof);
   
    for i =1:length(mem)
        coord=nodes(mem(i,:),:);
        mdof=tdof(i,:);
        %coord are member nodal coordinates
        x1 = coord(1,1); y1=coord(1,2);
        x2 = coord(2,1); y2=coord(2,2);
        L = sqrt((x2-x1)^2+(y2-y1)^2);
        cos = (x2-x1)/L; sin = (y2-y1)/L;
        %Member Transformation matrices
        trans = [cos sin 0 0; 0 0 cos sin];
        T{1,i}=trans; 
        %Member local stiffness matrices
        localk = E*A/L*[1 -1; -1  1];
        k{1,i}=localk;
        %Member Global stiffness matrices
        globalK = trans'*localk*trans;
        K{1,i}=globalK;
        %Structure stiffness matrix
        Kstr(mdof,mdof)=Kstr(mdof,mdof)+globalK;
    end   
    celldisp({T},'element Tranformation matrix');
    celldisp({k},'element local stiffness matrix');
    celldisp({K},'element global stiffness matrix');
    Kstr

[Dyuman Joshi]

You should not use built-in function names as names for variables, in this case cos and sin. Rename those variables to something else.

"How do I do it?"

How do you want to store the data in the excel file?

Assuming, E, A and L as scalars, each element is a

> 2x4 array in T

> 2x2 array in k

> 4x4 array in K

What should be the composition of the excel files for each variable? An example would be helpful.

You can store the data in arrays as well, instead of a cell array.

[VENKATA SRIHARSHA]

I'm saving the matrices in a cell array as I am using each matrix in each cell/element of respective cell arrays for further calculations. The only way to save an entire matrix into a single element in an array is a cell array. (As a simple array needs a number or string to be as it's element and so it won't take an entire matrix as it's element as it itself is in form of an array.)

Coming to my question, For example I've made a 3 member structure. So the functions loops through 3 members and derives 3 transformation matrices , 3 local and global stiffness matrices. Now first considering the transformation matrices, I'm saving the 3 transformation matrices in a cell array T. so T{1,i} will be a cell array of size 1x3 with each element being a 2x4 matrix.

Now i want all these matrices in each element of the cell array T to get exported out into an excel workbook which has 3 excel sheets and each sheet has each transformation matrix. And this i want to carry out similarly to local and global stiffness matrices. I want to know how to do it.

Answer 1

[Voss]

"... i want all these matrices in each element of the cell array T to get exported out into an excel workbook which has 3 excel sheets and each sheet has each transformation matrix. And this i want to carry out similarly to local and global stiffness matrices."

filename_T = 'Tranformation matrices.xlsx';
filename_k = 'local stiffness matrices.xlsx';
filename_K = 'global stiffness matrices.xlsx';

for ii = 1:numel(T)
    writematrix(T{ii},filename_T,'Sheet',ii);
end
for ii = 1:numel(k)
    writematrix(k{ii},filename_k,'Sheet',ii);
end
for ii = 1:numel(K)
    writematrix(K{ii},filename_K,'Sheet',ii);
end

[Dyuman Joshi]

@Voss, given that T,k and K are defined in the same loop, you can combine the 3 loops into a single one.

OP can also include the save calls of writematrix() inside the for loop that generate the corresponding data.

[Voss]

@Dyuman Joshi: Fair points.

Answer 2

[Harimurali]

Hi Venkata,

The "writematrix" function in MATLAB can be called inside a loop to export each matrix inside the cell array to seperate worksheets in the same Excel workbook.

Here is the sample MATLAB code to do the same:

cellArr = {ones(5), ones(4,5) .* 4, ones(2,3) .*2} % sample cell array containing matrices in each cell

filename = 'sample.xlsx'; % make sure that the Excel file is in the same path as this MATLAB script

for i = 1:length(cellArr)

writematrix(A{i},filename,'Sheet',i); % each matrix at the ith position in cell array will be written to Sheeti

end

Refer to the following documentation for information about the "writematrix" function:

https://www.mathworks.com/help/releases/R2023a/matlab/ref/writematrix.html

Hope this helps.