Operands could not be broadcast together with shapes. How can we address this problem

General
1 
 t1 = 0 
 for (i, t) in enumerate(T[1:]):
     print("t = %g" % (t))
     eps0t.t=t
     dt=t-t1
     K1 = inner(sigma_0(du,alpha),eps(v))*dx-inner(((1-alpha)**2+Constant(1e-6))* 
     (lmbda*tr(eps0)*Identity(ndim)),eps(v))*dx
     a, L = lhs(K1), rhs(K1)
     a_M = rho*inner(du,v)*dx
     M = lhs(a_M)
     solve(a+M == L, Accel, bcs)
     A           = M+betaN*dt*dt*a
     UN1T=UN0+dt*DUN0+(1./2.-betaN)*dt*dt*Accel
     DUN1T=DUN0+(1.-gamma)*dt*Accel
      K           = assemble(a)
      KK = K.array()

314 b = KK*UN1T
solve(A==L+b, Accel,bcs)

**Error message **
line 314, in
b = KK*UN1T
ValueError: operands could not be broadcast together with shapes (14760,14760) (2,)

2

You need to provide a minimal reproducable example, i.e. a code that reproduces the error message you are receiving.

3 
t1 = 0 
V_u=VectorFunctionSpace(mesh, "CG", 1)
UN1T=Function(V_u)
 for (i, t) in enumerate(T[1:]):
   
     print("t = %g" % (t))
     eps0t.t=t
     dt=t-t1
     K1 = inner(sigma_0(du,alpha),eps(v))*dx-inner(((1-alpha)**2+Constant(1e-6))* 
     (lmbda*tr(eps0)*Identity(ndim)),eps(v))*dx
     a, L = lhs(K1), rhs(K1)
     a_M = rho*inner(du,v)*dx
     M = lhs(a_M)
     solve(a+M == L, Accel, bcs)
     A           = M+betaN*dt*dt*a
     UN1T=UN0+dt*DUN0+(1./2.-betaN)*dt*dt*Accel
     DUN1T=DUN0+(1.-gamma)*dt*Accel
      K           = assemble(a)
      KK = K.array()
      b = KK*UN1T
      résoudre(A==L+b, Accel,bcs)


ValueError: operands could not be broadcast together with shapes (14760,14760) (2,)

This error comes from this code that I put above. especially at the level of b = KK*UN1T.
4

Your problem is not reproducible, as it cannot be copy pasted to another computer and then be executed. Please make sure all variables in your code are defined, and that the problem is as small as possible.