Hello, I am trying to convert FEniCS 2D field (scalar field or vector field) solutions and the corresponding x and y coordinates as 2D arrays in to separate Numpy arrays, got a bit confused by the conversion. Following is an example I am practicing on: from dolfin import * import numpy as np mesh…

for scalar fields, use xyz = V.tabulate_dof_coordinates() x = xyz[:,0] y = xyz[:,1] array = u.vector().get_local() For vector function spaces use V0 = V.sub(0).collapse() V1= V.sub(1).collapse() ux, uy = u.split(deepcopy=True) and then the same strategy as for scalar fields on each component.

Hello dokken, the above method gives 1D arrays only, I am trying to turn them into grid-like 2D arrays

Hi, I came across exactly the same issue as yours, do you still remember how you solved it?

fenics or fenicsx In fenicsx I did the following and it worked solver.solve(w) # saving data tol = 0.0001 # avoid hitting outside of domain den = 20 # take less points because the loop below is slow x = np.linspace(tol,1 - tol,den) y = np.concatenate([ np.linspace(tol,ep,np.int_(np.rint(bl_den…

Hi, thank you for your help! I’m using fenics, but when I ran w.split(), there are no return values and cannot be unpacked into three variables

Is the solver working? How is w defined. I used split because w in my code is a mixed function space. V = VectorElement("Lagrange", triangle, 2) # [ u,w] velocities Q = FiniteElement("Lagrange", triangle, 1) # pressure S = FiniteElement("Lagrange", triangle, 2) # free boundary problem W = Functi…

Thank you so much! I’ve solved the problem! Furthermore, have you ever tried a Navier-Stokes problem in Fenics. I’ve got outputs of a 2D velocity field and V = FunctionSpace(mesh, “Lagrange”, 2). In this situation, I cannot extract the data into numpy array.

Should V be a vector function space If it’s a funtionsapce you don’t need to use split

Convert FEniCS solution and coordinates to (numpy) 2D arrays

I/O

dokken May 3, 2020, 5:11am 5

See: Proper coordinates for eval()-method

Topic		Replies	Views
Convert a FEM solution function into an array dolfinx mesh , dolfinx	1	109	March 18, 2025
How to get the solution obtained by fenics as a vector?	13	4259	June 15, 2022
Saving solver outputs as numpy array and in csv files dolfinx	3	729	July 24, 2023
Is there an easy way to "convert" a numpy array to a dolfin Function? dolfinx	1	1751	January 15, 2021
VectorFunctionSpace solution corresponding to mesh	1	590	March 10, 2022

Convert FEniCS solution and coordinates to (numpy) 2D arrays

Related topics