Matrix with for cycle

Hello I want to create an i number of matrix with the arrangement that Qbar shows, but it generates a dimension error, what can I do?

for i=1:N
    a(i) = input('Direction [deg]: ');  
    theta_deg = a(i);
    theta_rad = theta_deg*pi/180;
        
    Qbar_11(i) = Q_11*((cos(theta_rad))^4)+2*(Q_12+2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_22*((sin(theta_rad))^4);
    Qbar_12(i) = (Q_11+Q_22-4*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_12*(((sin(theta_rad))^4)+((cos(theta_rad))^4));
    Qbar_22(i)= Q_11*((sin(theta_rad))^4)+2*(Q_12+2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_22*((cos(theta_rad))^4);
    Qbar_16(i) = (Q_11-Q_12-2*Q_66)*(sin(theta_rad))*((cos(theta_rad))^3)+(Q_12-Q_22+2*Q_66)*((sin(theta_rad))^3)*(cos(theta_rad));
    Qbar_26(i) = (Q_11-Q_12-2*Q_66)*((sin(theta_rad))^3)*(cos(theta_rad))+(Q_12-Q_22+2*Q_66)*(sin(theta_rad))*((cos(theta_rad))^3);
    Qbar_66(i) = (Q_11+Q_22-2*Q_12-2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_66*(((sin(theta_rad))^4)+((cos(theta_rad))^4));

    Qbar(i) = [Qbar_11(i),Qbar_12(i),Qbar_16(i);Qbar_12(i),Qbar_22(i),Qbar_26(i);Qbar_16(i),Qbar_26(i),Qbar_66(i)]
 
end

the error is ꃭ؀error: Codigo_V4: =: nonconformant arguments (op1 is 1x1, op2 is 3x3)

Answer 1

[madhan ravi]

Qbar = cell(N, 1); % preallocate properly for other variables also
Qbar{ii} = ... inside loop

[Carlos Betancur]

Thanks, but what I need is to sumation the Qbar(i) matrixs, but how they are in an array I don't know how to do it

[madhan ravi]

Qbar = cell(N, 1);
[Qbar_11, Qbar_12, Qbar_16,...
    Qbar_22, Qbar_26, Qbar_66] = deal(zeros(N, 1));
for ii = 1 : N
    a(ii) = input('Direction [deg]: ');  
    theta_deg = a(ii);
    theta_rad = theta_deg*pi/180;        
    Qbar_11(ii) = Q_11*((cos(theta_rad))^4)+2*(Q_12+2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_22*((sin(theta_rad))^4);
    Qbar_12(ii) = (Q_11+Q_22-4*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_12*(((sin(theta_rad))^4)+((cos(theta_rad))^4));
    Qbar_22(ii)= Q_11*((sin(theta_rad))^4)+2*(Q_12+2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_22*((cos(theta_rad))^4);
    Qbar_16(ii) = (Q_11-Q_12-2*Q_66)*(sin(theta_rad))*((cos(theta_rad))^3)+(Q_12-Q_22+2*Q_66)*((sin(theta_rad))^3)*(cos(theta_rad));
    Qbar_26(ii) = (Q_11-Q_12-2*Q_66)*((sin(theta_rad))^3)*(cos(theta_rad))+(Q_12-Q_22+2*Q_66)*(sin(theta_rad))*((cos(theta_rad))^3);
    Qbar_66(ii) = (Q_11+Q_22-2*Q_12-2*Q_66)*((sin(theta_rad))^2)*((cos(theta_rad))^2)+Q_66*(((sin(theta_rad))^4)+((cos(theta_rad))^4));
    Qbar{ii} = [Qbar_11(ii), Qbar_12(ii), Qbar_16(ii); Qbar_12(ii), Qbar_22(ii), Qbar_26(ii); Qbar_16(ii), Qbar_26(ii), Qbar_66(ii)];
end
celldisp(Qbar)

[Carlos Betancur]

I get an error when entering the last value of ii, so it does not create the last matrix Qbar{ii}.

error: Codigo_V5: Invalid resizing operation or ambiguous assignment to an out-of-bounds array ele

ment

thanks

[madhan ravi]

If you copied my code correctly, it’s highly unlikely to get that error message.

[Carlos Betancur]

Thanks !