I just updated to Ubuntu 18.04. The code that used to work normally now has the following error:
E_du = replace(E_u,{u:du})
NameError: name ‘replace’ is not defined
where,
elastic_energy = 0.5*inner(sigma(eps(u), alpha), eps(u))*dx
external_work = dot(body_force, u)*dx
dissipated_energy = Gc/c_w*(w(alpha)/ell + ell*dot(grad(alpha), grad(alpha)))dx #(w(alpha) + 0.5 * >ell**2 * w1dot ( grad ( alpha), grad ( alpha) )) * dx
total_energy = elastic_energy + dissipated_energy - external_work
#------------------------------------------------------------------------------------------
Weak form of elasticity problem. This is the formal expression
#------------------------------------------------------------------------------------------
for the tangent problem which gives us the equilibrium equations.
E_u = derivative(total_energy,u,v)
E_alpha = derivative(total_energy,alpha,beta)Hessian matrix
E_alpha_alpha = derivative(E_alpha,alpha,dalpha)
Writing tangent problems in term of test and trial functions for matrix assembly
E_du = replace(E_u,{u:du})
E_dalpha = replace(E_alpha,{alpha:dalpha})
Thank you advance.