Call a element of Varying Column vector

Kt=rand(6,6);

u=rand(6,6);

for i=1:1:6

for n=1:1:5

fr(:, i)=Kt*u(:,i) % i am try to call earch column of u here for multiplying with Kt, if i am wrong please correct me.

eval(['fr',num2str(n),'=Kt*u(:,i)'])

end

end

%%% Now i want to call each element of fr one by one how can i call it.

Answer 1

[David Hill]

Hard to understand what you are trying to do. Eval statement makes no sense as well as the douple for-loop. Eval would be overriding each i-loop to the same values. Why not just:

Kt=rand(6,6);
u=rand(6,6);
fr=Kt*u;

Then index into fr. To call each element in fr,

for k=1:numel(fr)
    fr(k)
end

[Chaudhary P Patel]

@David Hill , sir for fr , i have to call every column of u as column vector (6X1) not as a matrix (6X6) for each value of i.

[Chaudhary P Patel]

i have to find fr1 fr2 fr3 fr4 fr5 for each column vector of u and after that i want to take each element of fr1 fr2 fr3 fr4 fr5 one by one.

[David Hill]

fr above is the same as:

Kt=rand(6,6);
u=rand(6,6);
for i=1:6
    fr(:, i)=Kt*u(:,i);
end

The n-loop makes no sense and will not change fr (no 'n' in the equation).

I don't understand your comment. Please provide an example of your expected output.

[Chaudhary P Patel]

Ok Sir, in actual code u is evaluated for each loop as a 6X1, For understanding i maintned here as a 6X6 matrix.

For each loop, simultaneolsy i have to calculate fr that will be fr1, fr2, fr3, fr4,....... for each loop

now next steps in coding i have to extract each element of fr1, fr2, fr3, fr4,....

i want to know that how can i extract the each element for each fr1, fr2, fr3, fr4,....

[David Hill]

Very bad idea to have different variable names (fr1, fr2, fr3, ...). You should have just one matrix and index into it.

Kt=rand(6,6);
for n=1:5
  u=rand(6,1);%since your u changes based on calculations
  fr(:,n)=Kt*u;
end
%now fr will be 6x5 matrix with each column of fr being (fr1,fr2,fr3,fr4,fr5)
%extracting elements from fr1.... is easy
element=5;fr_number=3;%if you want element 5 from fr3
fr(element,fr_number)

[Chaudhary P Patel]

sir, @David Hill ,what i am exactly want, i am unable to explain here without complete code. sir i mailed you. please reply me.

[Chaudhary P Patel]

@David Hill sir, please correct me.

ut=rand(15,1);

uy=([0.84;0.384;0.784]);

eval (['U_y','=[u_y;u_y;u_y;u_y;u_y]']);

for n=1:15

if ut(n,1)<=U_y(n,1)

ut(n,1)=ut(n,1);

else

ut(n,1)=0;

end

utt(:,1)=ut(n,1); %% i want to store the ut as a utt in a column

end