[petsc-users] oddity in MatTranspose() under petsc4py

[Ethan Coon]

First, apologies for not looking into this more closely, but I wanted to
make sure I wasn't missing something stupid before I rebuilt petsc-dev
and petsc4py-dev and started writing PETSc-only versions to see what is
going on.

See the following odd result:


In [1]: from petsc4py import PETSc

In [2]: import numpy as np

In [3]: n = [0,1]

In [4]: vals = np.array([[0,1],[0,0]], 'd')

In [5]: A = PETSc.Mat().createAIJ(2,2)

In [6]: A.assemble()

In [7]: B = A.duplicate()

In [8]: B.setValues(n,n,vals, PETSc.InsertMode.ADD_VALUES)

In [9]: B.assemble()

In [10]: B.transpose(out=A)
Out[10]: <petsc4py.PETSc.Mat at 0x2afb7e0>

In [11]: A.view()
Matrix Object: 1 MPI processes
  type: seqbaij
row 0: (0, 0)  (1, 0) 
row 1: (0, 1)  (1, 0) 

In [12]: vals
Out[12]: 
array([[ 0.,  1.],
       [ 0.,  0.]])

In [13]: A.setValues(n,n,-vals.transpose(), PETSc.InsertMode.ADD_VALUES)

In [14]: A.assemble()

In [15]: A.view()
Matrix Object: 1 MPI processes
  type: seqbaij
row 0: (0, 0)  (1, -1) 
row 1: (0, 1)  (1, 0) 

where I would have expected A to be all zeros...

This is on petsc4py-3.3 and petsc-3.3-p5, and I know this code worked on
older versions of petsc4py/petsc.  If I'm not missing something dumb
I'll look a little closer into whether it is PETSc or petsc4py...

Thanks,

Ethan



-- 
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Ethan Coon
Post-Doctoral Researcher
Applied Mathematics - T-5
Los Alamos National Laboratory
505-665-8289

http://www.ldeo.columbia.edu/~ecoon/
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