it is not working.

%%%%%%%%%%%%%% acceleration matrix %%%%%%%%%%%%%%
for g=1:1:10
for i=1:ne
    Ecc=eval(['Ee',num2str(i)]);
if (i<166)&&(i>420)
        ug=[0.3*Ug(g,2);Ug(g,2);0;Ecc*Ug(g,2);0.3*Ug(g,2);Ug(g,2);0;Ecc*Ug(g,2)];
        if (i>165)&&(i<421)
            ug=[Ug(g,2);0.3*Ug(g,2);0;Ecc*Ug(g,2);Ug(g,2);0.3*Ug(g,2);0;Ecc*Ug(g,2)];
            eval(['f',num2str(i),'=MGf.ug']);
            t=eval(['T',num2str(i)]);
            ff=eval(['f',num2str(i),'l']);%Calling local acceleration matrix
            eval(['f',num2str(i),'g','=transpose(t).*ff.*t']);%Evaluation acceleration  matrix in global coordinate system   
        end
end
end
end

[Stephen23]

"it is not working."

... because it is badly wrritten, badly aligned, badly designed code.

Sorry, but that code should be thrown away and replaced with simpler, more efficient code that actually uses arrays and indexing properly. It is a complete waste of MATLAB to use eval for every trivial operation and for accessing data. That code calls eval seven times, on nearly half of the code lines, which is very bad design makes the code slow, complex, obfuscated, buggy, and very difficult to debug, and is exactly why the MATLAB documentation and all experienced users recommend avoiding writing such pointlessly slow, complex, buggy code like this:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

You need to learn how to use arrays.

You need to learn how to use indexing.

You need to avoid eval for such trivial code like this.

Start by doing the introductory tutorials, which show how to create and access data in arrays (and don't use eval at all):

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

[John D'Errico]

@pramod kumar:

Please learn to use comments instead of answers if you are not providing an answer. Answer movect to a comment:

"please help how to correct it."

Answer 1

[Chaudhary P Patel]

sir i correct it but now i am getting difficulties in assembling the global force vector, please giive me some clue.

[Walter Roberson]

What is your revised code?

[Chaudhary P Patel]

for j=1%:1:10

for i=1:ne

Ecc=eval(['Ee',num2str(i)]);

if (i<=165)

acc=[0.3*Ug(j,1);Ug(j,1);0;Ecc.*(Ug(j,1))';0.3*Ug(j,1);Ug(j,1);0;Ecc.*(Ug(j,1))'];

elseif (i>165)&&(i<=420)

acc=[Ug(j,1);0.3*Ug(j,1);0;Ecc.*(Ug(j,1))';Ug(j,1);0.3*Ug(j,1);0;Ecc.*(Ug(j,1))'];

else (i>420);

acc=[0.3*Ug(j,1);Ug(j,1);0;Ecc.*(Ug(j,1))';0.3*Ug(j,1);Ug(j,1);0;Ecc.*(Ug(j,1))'];

end

mas = eval(['m',num2str(i)]); %% calling global elemental mass matrix

eval(['force',num2str(i),'=mas*acc']);

end

end

[Chaudhary P Patel]

sir help me how to assemble global force vector.

[Walter Roberson]

You said that you corrected the code but it is still full of eval()

None of the regular volunteers is likely to take the question seriously until the code is rewritten so that it does not use eval.

[Chaudhary P Patel]

sir actually i am working with eval() from learning and works too.

[Walter Roberson]

The problem with your code is that it uses eval. It will never work correctly unless you get rid of all the eval.

[Chaudhary P Patel]

sir leave the queastion, tell me one thing how to assemble the global force vector.

[Chaudhary P Patel]

ok sir i will try to not use eval() in future but tel the way how to assemble of global vector.

[Stephen23]

"...tell me one thing how to assemble the global force vector."

Write the code without eval.

Once you do that, then you can trivially use indexing to allocate to your "global force vector" (and also use all of the standard, inbuilt code helping tools to help debug your code). For as long as you use eval like that, your code will be slow, complex, buggy, hard to debug, and will continue to waste your time.