Maniplate mesh coordinates based on marker

mesh
1

I would like to change the coordinate of mesh based on the marker.
Specifically, I would like to change the coordinates at the boundary of 3D mesh.

Following is the small example of what I want to do.

from fenics import *

mesh = UnitSquareMesh(32,32)
bdry= MeshFunction("size_t", mesh, mesh.geometry().dim() - 1, mesh.domains())
CompiledSubDomain("x[0] < 0 + 1e-12").mark(bdry, 1)

I know it is possible to change the coordinate with something like

x = mesh.coordinates()
x[:,1] = some manipulation

However, is it possible to do the same manipulation based on the boundary marker ??

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2

I’m a bit rusty with old DOLFIN, but hopefully the following helps

from dolfin import *

mesh = UnitSquareMesh(32,32)
bdry_verts_mf = MeshFunction("bool", mesh, 0, False)
CompiledSubDomain("x[0] < 0 + 1e-12").mark(bdry_verts_mf, True)

for v in bdry_verts_mf.where_equal(True):
	mesh.coordinates()[v,0] -= 0.1

import matplotlib.pyplot as plt
plot(mesh)
plt.show()

I just want to warp the vertices on the left boundary by (-0.1, 0)^\top.

image

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