#!/usr/bin/env python

"""
Created on Wed Jun 29 22:05:59 2016

@author: daneel@utexas.edu
"""

import numpy as np
from petsc4py import PETSc
Print = PETSc.Sys.Print

matsize = 100
filename = 'tmpMatrix-A.dat'

A = PETSc.Mat().create(PETSc.COMM_WORLD)
A.setSizes([matsize, matsize])
#A.setType(PETSc.Mat.Type.DENSE)
A.setUp()

Istart, Iend = A.getOwnershipRange()
for I in xrange(Istart, Iend) :
    A[I,:] = np.random.random(matsize)

A.assemble()
Print("Random matrix assembled. Now writing to temporary file ...")
# save
viewer = PETSc.Viewer().createBinary(filename, 'w')
viewer.pushFormat(viewer.Format.NATIVE)
viewer.view(A)
Print("Written to ", filename)
# reload
Print("Now reloading from ", filename)
viewer_new = PETSc.Viewer().createBinary(filename, 'r')    
viewer_new.pushFormat(viewer.getFormat())
A_new = PETSc.Mat().load(viewer_new)
assert A_new.equal(A), "Reload unsuccessful"
Print("Reload successful")