FIPY: problem with Grid2D cellToFaceDistanceVectors gives error 'UniformGrid2D' object has no attribute '_cellToFaceDistanceVectors'

问题

I create a mesh using Grid2D as follows

L = 2.
N = 50
dL = L/N
mesh = Grid2D(nx=N, ny=N, dx=dL, dy=dL)

but when I try to get the cell to face distance vector:

mesh.cellToFaceDistanceVectors

the following error appears:

AttributeError                            Traceback (most recent call last)

<ipython-input-7-9ab623a3d90d> in <module>()
----> 1 mesh.cellToFaceDistanceVectors

/usr/local/lib/python3.6/dist-packages/fipy/meshes/abstractMesh.py in <lambda>(s)
     96                             rank=1)
     97 
---> 98     cellToFaceDistanceVectors  = property(lambda s: s._cellToFaceDistanceVectors)
     99     cellDistanceVectors        = property(lambda s: s._cellDistanceVectors)
    100     cellVolumes                = property(lambda s: s._scaledCellVolumes)

AttributeError: 'UniformGrid2D' object has no attribute '_cellToFaceDistanceVectors'

It happens the same for other attributes such as:

mesh.cellDistanceVectors

Does anybody know how can I get the face to cell distance vectors?

回答1:

It doesn't look like we ever implemented that for Grids and it looks like I never did much testing of the Robin discussion. I've filed an issue.

As a workaround, you can do

from fipy.tools import numerix
MA = numerix.MA

tmp = MA.repeat(mesh._faceCenters[..., numerix.NewAxis,:], 2, 1)
cellToFaceDistanceVectors = tmp - numerix.take(mesh._cellCenters, mesh.faceCellIDs, axis=1)

tmp = numerix.take(mesh._cellCenters, mesh.faceCellIDs, axis=1)
tmp = tmp[..., 1,:] - tmp[..., 0,:]
cellDistanceVectors = MA.filled(MA.where(MA.getmaskarray(tmp), cellToFaceDistanceVectors[:, 0], tmp))

来源：https://stackoverflow.com/questions/60073399/fipy-problem-with-grid2d-celltofacedistancevectors-gives-error-uniformgrid2d