I am getting this error "Assignment has more non-singleton rhs dimensions than non-singleton subscripts". Please help. Mw, Cw and Kw are 243X243 matrices.

t_init = 0; t_final = 3;

t_incr = 0.005;

n = (t_final-t_init)/t_incr;

tt = t_init:t_incr:t_final;

trange = [t_init t_final];

F(1,:) = 0*tt;

F(2,:) = 0*tt;

omega = pi/.29;

F(243,:) = 50*sin(omega*tt);

for j = 1:n

pulse(j) = sin(omega*tt(j));

if tt(j) > pi/omega

pulse(j) = 0;

end

end

F(243,1:n) = 50*pulse;

x0=zeros(1,243);

xd0=zeros(1,243);

%newwmark betta method

% M, C, K are matrices multiplying xddot, xdot and x repectively

% F is column vector of exciations. x0, xd0 are initial x0 and xd vectors

tspan = [t_init t_final]; %n is tspan/t_increment

dt = (tspan(2)-tspan(1))/n;

tp(1) = tspan(1);

x(:,1) = x0'; --------------------ERROR LINE--------------------------------------------- THIS IS THE ERROR LINE----------------------------ERROR LINE---------------------------------

xd(:,1) = xd0';

gamma = 1/2; beta = 1/4;

A = (1/(beta*dt^2))*Mw+(gamma/(beta*dt))*Cw+Kw; invA = inv(A);

xdd(:,1) = inv(Mw)*(F(:,1)-Cw*xd(:,1)-Kw*x(:,1));

for i = 1:n

B = (F(:,i+1)+Mw*((1/(beta*dt^2))*x(:,i)+(1/(beta*dt))*xd(:,i)+(1/(2*beta)-1)*xdd(:,i))+Cw*((gamma/(beta*dt))*x(:,i)+(gamma/beta-1)*xd(:,i)+(gamma/beta-2)*(dt/2)*xdd(:,i)));

x(:,i+1) = invA*B;

xdd(:,i+1) = (1/(beta*dt^2))*(x(:,i+1)-x(:,i))-(1/(beta*dt))*xd(:,i)-((1/(2*beta))-1)*xdd(:,i);

xd(:,i+1) = xd(:,i)+(1-gamma)*dt*xdd(:,i)+gamma*dt*xdd(:,i+1);

tp(i+1) = tp(i)+dt;

end

x = x';

x1 = 1000*x;

figure(1), plot(tp,x1(:,1),'k',tp,x1(:,2),'k',tp,x1(:,3),'k',tp,0*tp,'k')

xlabel('Time, s')

ylabel('x, mm')

axis([0 3 -5 10])

hold on

figure(1), plot(tt(1:60),5*pulse(1:60),'.k')

hold off

[t,x2] = ode45('f10',t_init:t_incr:t_final,[0 0 0 0 0 0]);

x2 = 1000*x2;

d(:,1) = (x1(:,1)-x2(:,1));

d(:,2) = (x1(:,2)-x2(:,2));

d(:,3) = (x1(:,3)-x2(:,3));

figure(2), plot(tp,d(:,1),'k',tp,d(:,2),'k',tp,d(:,3),'k',tp,0*tp,'k')

xlabel('Time, s')

ylabel('Difference, mm')

axis([0 3 -1e-2 1e-2])

Answer 1

[Alan Stevens]

It gets past your indicated Error line for me, but fails because you haven't defined Mw, Cw or Kw.