Store all matrices of "for" loop to a file

Dear all,

I have problem of output data "T" (5x4 matrix) of "for loop" to a file, e.g., cvs format. I know that "csvwrite('Data.csv',T)" in the following code is only output the final value of T. I would like to store all "T" matrices in one file. Hope to receive your guilding. Thanks a lot!

A =[ 0 2 6 4 5 2 1

2 0 0 0 0 0 1

0 0 2 1 0 0 1

0 0 0 0 1 1 0];

b = [5.8; 2.4; 1.6; 0.2];

% select 4 columns from 7 columns

colsets = nchoosek(1:7,4);

nCombinations = size(colsets,1) % number of combinations

for i = 1:nCombinations

a = A(:,colsets(i,:));

if rank(a) >= 4

x = a \ b;

if (x(:,:)>=0) & (x(:,:)~=Inf)

T = [a;x'] % 5x4 matrix

csvwrite('Data.csv',T);

end

end

end

Answer 1

[Ameer Hamza]

Try this

A =[ 0     2     6     4     5     2     1
    2     0     0     0     0     0     1
    0     0     2     1     0     0     1
    0     0     0     0     1     1     0];
b = [5.8; 2.4; 1.6; 0.2];
% select 4 columns from 7 columns
colsets = nchoosek(1:7,4);
nCombinations = size(colsets,1) % number of combinations
T = [];
for i = 1:nCombinations
    a = A(:,colsets(i,:));
    if rank(a) >= 4
        x = a \ b;
        if (x(:,:)>=0) & (x(:,:)~=Inf)
            T = [T;a;x'] % 5x4 matrix
        end
    end
end
csvwrite('Data.csv',T);

Alternatively, if you have R2019a or later

A =[ 0     2     6     4     5     2     1
    2     0     0     0     0     0     1
    0     0     2     1     0     0     1
    0     0     0     0     1     1     0];
b = [5.8; 2.4; 1.6; 0.2];
% select 4 columns from 7 columns
colsets = nchoosek(1:7,4);
nCombinations = size(colsets,1) % number of combinations
for i = 1:nCombinations
    a = A(:,colsets(i,:));
    if rank(a) >= 4
        x = a \ b;
        if (x(:,:)>=0) & (x(:,:)~=Inf)
            T = [a;x'] % 5x4 matrix
            writematrix(T, 'Data.csv', 'WriteMode', 'append');
        end
    end
end

[Thuy Tran]

Thanks a lot! It really helpful to me. When I have R2019a or later, I will try the second way.

[Ameer Hamza]

I am glad to be of help!