Merge branch 'master'

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diff --git a/samples/matlab/s017_opTomo.m b/samples/matlab/s017_opTomo.m
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+% -----------------------------------------------------------------------
+% This file is part of the ASTRA Toolbox
+% 
+% Copyright: 2010-2015, iMinds-Vision Lab, University of Antwerp
+%            2014-2015, CWI, Amsterdam
+% License: Open Source under GPLv3
+% Contact: astra@uantwerpen.be
+% Website: http://sf.net/projects/astra-toolbox
+% -----------------------------------------------------------------------
+
+% This sample illustrates the use of opTomo.
+%
+% opTomo is a wrapper around the FP and BP operations of the ASTRA Toolbox,
+% to allow you to use them as you would a matrix.
+%
+% This class requires the Spot Linear-Operator Toolbox to be installed.
+% You can download this at http://www.cs.ubc.ca/labs/scl/spot/
+
+% load a phantom image
+im = phantom(256);
+% and flatten it to a vector
+x = im(:);
+
+%% Setting up the geometry
+% projection geometry
+proj_geom = astra_create_proj_geom('parallel', 1, 256, linspace2(0,pi,180));
+% object dimensions
+vol_geom  = astra_create_vol_geom(256,256);
+
+%% Generate projection data
+% Create the Spot operator for ASTRA using the GPU.
+W = opTomo('cuda', proj_geom, vol_geom);
+
+p = W*x;
+
+% reshape the vector into a sinogram
+sinogram = reshape(p, W.proj_size);
+imshow(sinogram, []);
+
+
+%% Reconstruction
+% We use a least squares solver lsqr from Matlab to solve the 
+% equation W*x = p.
+% Max number of iterations is 100, convergence tolerance of 1e-6.
+y = lsqr(W, p, 1e-6, 100);
+
+% the output is a vector, so we reshape it into an image
+reconstruction = reshape(y, W.vol_size);
+
+subplot(1,3,1);
+imshow(reconstruction, []);
+title('Reconstruction');
+
+subplot(1,3,2);
+imshow(im, []);
+title('Ground truth');
+
+% The transpose of the operator corresponds to the backprojection.
+backProjection = W'*p;
+subplot(1,3,3);
+imshow(reshape(backProjection, W.vol_size), []);
+title('Backprojection');
diff --git a/samples/python/s017_OpTomo.py b/samples/python/s017_OpTomo.py
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+#-----------------------------------------------------------------------
+#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)