Hello,
I would like to ask if there is an option to retain an intermediate expression when using FFC to convert a .ufl file to a .h file. For example, here is the HyperElasticity.ufl from FEniCS demo:
# Function spaces
element = VectorElement("Lagrange", tetrahedron, 1)
# Trial and test functions
du = TrialFunction(element) # Incremental displacement
v = TestFunction(element) # Test function
# Functions
u = Coefficient(element) # Displacement from previous iteration
B = Coefficient(element) # Body force per unit volume
T = Coefficient(element) # Traction force on the boundary
# Kinematics
d = u.geometric_dimension()
I = Identity(d) # Identity tensor
F = I + grad(u) # Deformation gradient
C = F.T*F # Right Cauchy-Green tensor
# Invariants of deformation tensors
Ic = tr(C)
J = det(F)
# Elasticity parameters
mu = Constant(tetrahedron)
lmbda = Constant(tetrahedron)
# Stored strain energy density (compressible neo-Hookean model)
psi = (mu/2)*(Ic - 3) - mu*ln(J) + (lmbda/2)*(ln(J))**2
# Total potential energy
Pi = psi*dx - inner(B, u)*dx - inner(T, u)*ds
# First variation of Pi (directional derivative about u in the direction of v)
F = derivative(Pi, u, v)
# Compute Jacobian of F
J = derivative(F, u, du)
After obtaining the HyperElasticity.h using FFC, I want to compute the value of psi, for example, then it seems that I have to define again the expression for psi in the main.cpp?
Thank you very much.
dtruong27
