Hello
I’m trying to plot a vector-valued function (ndim=2) over an interval using VectorFunctionSpace and IntervalMesh but when I run plot I get an AttributeError: Vector length must match geometric dimension..
Can anyone give me a hint on why this happens and/or how to fix it?
I’m using fenics from this docker image: quay.io/fenicsproject/stable:current from a jupyter notebook cell in jupyter lab.
Thanks!
import fenics
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
Lx = 10
nx = 10
mesh = fenics.IntervalMesh(nx-1, 0, Lx)
W = fenics.VectorFunctionSpace(mesh, 'P', 1, dim=2)
f1 = fenics.Expression(('cos(x[0])', 'sin(x[0])'), element = W.ufl_element())
u = fenics.interpolate(f1, W)
fenics.plot(u)
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-6-541afb7716b5> in <module>
----> 1 fenics.plot(u)
/usr/local/lib/python3.6/dist-packages/dolfin/common/plotting.py in plot(object, *args, **kwargs)
436 # Plot
437 if backend == "matplotlib":
--> 438 return _plot_matplotlib(object, mesh, kwargs)
439 elif backend == "x3dom":
440 return _plot_x3dom(object, kwargs)
/usr/local/lib/python3.6/dist-packages/dolfin/common/plotting.py in _plot_matplotlib(obj, mesh, kwargs)
302
303 if isinstance(obj, cpp.function.Function):
--> 304 return mplot_function(ax, obj, **kwargs)
305 elif isinstance(obj, cpp.function.Expression):
306 return mplot_expression(ax, obj, mesh, **kwargs)
/usr/local/lib/python3.6/dist-packages/dolfin/common/plotting.py in mplot_function(ax, f, **kwargs)
199 nv = mesh.num_vertices()
200 if len(w0) != gdim * nv:
--> 201 raise AttributeError('Vector length must match geometric dimension.')
202 X = mesh.coordinates()
203 X = [X[:, i] for i in range(gdim)]
AttributeError: Vector length must match geometric dimension.