[BUG]: can't integrate the inner product of the gradient of a 3D vector and itself over the domain using dolfinx.fem.assemble

[ruf10]

How to reproduce the bug

I try to calculate the volume of my domain/mesh, and fem.assemble_scalar is not working, also I try to calculate the integral of nabla_grad of a vector inner product with itself over the domain, its also returns me the error: Can anyone help me with that quickly?

Thank you!

Best, RUi

Minimal Example (Python)

F = (1./dt)*inner(u,v)*dx + eps*p*q*dx +b(un,u,v)*dx +2.*nu*a_sym(u,v)*dx
        F += - c(p,v)*dx+ c(q,u)*dx +nu_t*a_sym(u,v)*dx
        F -= (1./dt)*(inner(un,v))*dx
        unPlus1, pnPlus = solve_u(F, t)

        def grad_sym(u):
            return 0.5 * (nabla_grad(u) + nabla_grad(u).T)

        def frobenius_norm_squared(T):
            return ufl.inner(T, T)

        u_Sym = grad_sym(unPlus1)
        frobenius_norm_squared_u_Sym = frobenius_norm_squared(u_Sym)

        # Define measure for integration over the domain
        dx = ufl.dx(domain=msh)

        # Define form for integral
        M_form = frobenius_norm_squared_u_Sym * dx

        # Assemble integral over the domain
        M = dolfinx.fem.assemble.assemble_scalar(M_form)

Output (Python)

Traceback (most recent call last):
  File "/Users/ruifang/ct.py", line 481, in <module>
    M = dolfinx.fem.assemble.assemble_scalar(M_form)
  File "/Users/ruifang/opt/anaconda3/envs/fenicsx-env/lib/python3.10/site-packages/dolfinx/fem/assemble.py", line 125, in assemble_scalar
    constants = constants or _pack_constants(M)
TypeError: pack_constants(): incompatible function arguments. The following argument types are supported:
    1. (form: dolfinx::fem::Form<float>) -> numpy.ndarray[numpy.float32]
    2. (e: dolfinx::fem::Expression<float>) -> numpy.ndarray[numpy.float32]
    3. (form: dolfinx::fem::Form<double>) -> numpy.ndarray[numpy.float64]
    4. (e: dolfinx::fem::Expression<double>) -> numpy.ndarray[numpy.float64]
    5. (form: dolfinx::fem::Form<std::__1::complex<float> >) -> numpy.ndarray[numpy.complex64]
    6. (e: dolfinx::fem::Expression<std::__1::complex<float> >) -> numpy.ndarray[numpy.complex64]
    7. (form: dolfinx::fem::Form<std::__1::complex<double> >) -> numpy.ndarray[numpy.complex128]
    8. (e: dolfinx::fem::Expression<std::__1::complex<double> >) -> numpy.ndarray[numpy.complex128]

Invoked with: Form([Integral(Inner(ComponentTensor(Product(FloatValue(0.5), Indexed(Sum(NablaGrad(Coefficient(FunctionSpace(Mesh(VectorElement(Basix element (P, tetrahedron, 1, equispaced, unset, False), 3), 0), VectorElement(FiniteElement('Lagrange', tetrahedron, 2), dim=3)), 115)), Transposed(NablaGrad(Coefficient(FunctionSpace(Mesh(VectorElement(Basix element (P, tetrahedron, 1, equispaced, unset, False), 3), 0), VectorElement(FiniteElement('Lagrange', tetrahedron, 2), dim=3)), 115)))), MultiIndex((Index(3700), Index(3701))))), MultiIndex((Index(3700), Index(3701)))), ComponentTensor(Product(FloatValue(0.5), Indexed(Sum(NablaGrad(Coefficient(FunctionSpace(Mesh(VectorElement(Basix element (P, tetrahedron, 1, equispaced, unset, False), 3), 0), VectorElement(FiniteElement('Lagrange', tetrahedron, 2), dim=3)), 115)), Transposed(NablaGrad(Coefficient(FunctionSpace(Mesh(VectorElement(Basix element (P, tetrahedron, 1, equispaced, unset, False), 3), 0), VectorElement(FiniteElement('Lagrange', tetrahedron, 2), dim=3)), 115)))), MultiIndex((Index(3700), Index(3701))))), MultiIndex((Index(3700), Index(3701))))), 'cell', Mesh(VectorElement(Basix element (P, tetrahedron, 1, equispaced, unset, False), 3), 0), 'everywhere', {}, None)])

Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,
<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic
conversions are optional and require extra headers to be included
when compiling your pybind11 module.

Version

main branch

DOLFINx git commit

No response

Installation

No response

Additional information

No response

[IgorBaratta]

Could you try calling form first, eg:

from dolfinx.fem import form
....
M_form = form(M_form) # JIT
M = dolfinx.fem.assemble.assemble_scalar(M_form)

[ruf10]

thank you so much!!! it works!