Hi everyone. Recently, I try to convert my program based on FEniCS 2019 to the new version FEniCSx. I meet a problem for transforming the following code to the current version due to lack of some functions, e.g., dolfin_element.evaluate_basis_all import fenics as fe def construct_measurement_matri…

due to lack of some functions, e.g., dolfin_element.evaluate_basis_all You may want to have a look at Creating and tabulating an element — Basix 0.7.0 documentation You may also want to show us the parts of the code you already did manage to convert from FEniCS to FEniCSx. You can expect the com…

Sorry for not posting my current parts of the code. I am not an expert for programming finite element methods, just use the functionals of FEniCSx to solve some inverse problems. FEniCSx provides a quick and convenient tool to test Bayesian or optimization inverse algorithms without too much attenti…

What you are searching for is how to create a point source. Following is code for getting the basis functions evaluated at a point in the cell: # Author: Jørgen S. Dokken # # Create a point source import dolfinx from mpi4py import MPI import numpy as np import ufl def compute_cell_contributions…

Thank you very much for your code, I will study your code carefully.

Thanks again for your codes. Based on your code, I rewrite the codes as follows, which seems work well. import dolfinx from dolfinx import fem, la, geometry from dolfinx.fem import assemble_matrix, assemble_vector import ufl from mpi4py import MPI def construct_measure_matrix(V, points): ''' …

Use u.dx(i) in the Expression for the i-th directional derivative.

What’s the most straight-forward way to insert values into a vector (say the rhs vector of a LinearProblem object)? I’ve looked at the documentation for the LinearProblem class and I didn’t see any method allowing the insertion of values corresponding to specific cells.

You can access the underlying vector in LinearProblem by: https://docs.fenicsproject.org/dolfinx/v0.7.3/python/generated/dolfinx.fem.petsc.html#dolfinx.fem.petsc.LinearProblem.b To insert for specific values in specific cells, you would have to be way more specific, as to how the values relate to …

How to construct a sparse matrix used for calculating function values at multiple points

dolfinx

Ekrem_Ekici December 19, 2023, 4:44pm 7

Hello,

How can you get the basis derivatives of the specific cell based on your code?

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How to construct a sparse matrix used for calculating function values at multiple points

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