#-----------------------------------------------------------------------
#Copyright 2013 Centrum Wiskunde & Informatica, Amsterdam
#
#Author: Daniel M. Pelt
#Contact: D.M.Pelt@cwi.nl
#Website: http://dmpelt.github.io/pyastratoolbox/
#
#
#This file is part of the Python interface to the
#All Scale Tomographic Reconstruction Antwerp Toolbox ("ASTRA Toolbox").
#
#The Python interface to the ASTRA Toolbox is free software: you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.
#
#The Python interface to the ASTRA Toolbox is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with the Python interface to the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.
#
#-----------------------------------------------------------------------

import astra
import numpy as np
import scipy.sparse.linalg

vol_geom = astra.create_vol_geom(256, 256)
proj_geom = astra.create_proj_geom('parallel', 1.0, 384, np.linspace(0,np.pi,180,False))

# As before, create a sinogram from a phantom
import scipy.io
P = scipy.io.loadmat('phantom.mat')['phantom256']
proj_id = astra.create_projector('cuda',proj_geom,vol_geom)

# construct the OpTomo object
W = astra.OpTomo(proj_id)

sinogram = W * P
sinogram = sinogram.reshape([180, 384])

import pylab
pylab.gray()
pylab.figure(1)
pylab.imshow(P)
pylab.figure(2)
pylab.imshow(sinogram)

# Run the lsqr linear solver
output = scipy.sparse.linalg.lsqr(W, sinogram.flatten(), iter_lim=150)
rec = output[0].reshape([256, 256])

pylab.figure(3)
pylab.imshow(rec)
pylab.show()

# Clean up.
astra.projector.delete(proj_id)