From 4843e28a6666b9557dc7550a9fc056adee4c21c8 Mon Sep 17 00:00:00 2001
From: Willem Jan Palenstijn <Willem.Jan.Palenstijn@cwi.nl>
Date: Mon, 29 Aug 2016 14:07:20 +0200
Subject: Add CGLS plugin

---
 python/astra/plugins/__init__.py |  1 +
 python/astra/plugins/cgls.py     | 99 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 python/astra/plugins/cgls.py

(limited to 'python/astra')

diff --git a/python/astra/plugins/__init__.py b/python/astra/plugins/__init__.py
index a24b04d..71e9b64 100644
--- a/python/astra/plugins/__init__.py
+++ b/python/astra/plugins/__init__.py
@@ -25,4 +25,5 @@
 
 
 from .sirt import SIRTPlugin
+from .cgls import CGLSPlugin
 
diff --git a/python/astra/plugins/cgls.py b/python/astra/plugins/cgls.py
new file mode 100644
index 0000000..2f4970b
--- /dev/null
+++ b/python/astra/plugins/cgls.py
@@ -0,0 +1,99 @@
+# -----------------------------------------------------------------------
+# Copyright: 2010-2016, iMinds-Vision Lab, University of Antwerp
+#            2013-2016, CWI, Amsterdam
+#
+# Contact: astra@uantwerpen.be
+# Website: http://sf.net/projects/astra-toolbox
+#
+# This file is part of the ASTRA Toolbox.
+#
+#
+# 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 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 ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.
+#
+# -----------------------------------------------------------------------
+
+
+import astra
+import numpy as np
+import six
+
+class CGLSPlugin(astra.plugin.base):
+    """CGLS."""
+
+    astra_name = "CGLS-PLUGIN"
+
+    def initialize(self,cfg):
+        self.W = astra.OpTomo(cfg['ProjectorId'])
+        self.vid = cfg['ReconstructionDataId']
+        self.sid = cfg['ProjectionDataId']
+
+        try:
+            v = astra.data2d.get_shared(self.vid)
+            s = astra.data2d.get_shared(self.sid)
+            self.data_mod = astra.data2d
+        except Exception:
+            v = astra.data3d.get_shared(self.vid)
+            s = astra.data3d.get_shared(self.sid)
+            self.data_mod = astra.data3d
+
+    def run(self, its):
+        v = self.data_mod.get_shared(self.vid)
+        s = self.data_mod.get_shared(self.sid)
+        z = np.zeros(v.shape, dtype=np.float32)
+        p = np.zeros(v.shape, dtype=np.float32)
+        r = np.zeros(s.shape, dtype=np.float32)
+        w = np.zeros(s.shape, dtype=np.float32)
+        W = self.W
+
+        # r = s - W*v
+        W.FP(v, out=w)
+        r[:] = s
+        r -= w
+
+        # p = W'*r
+        W.BP(r, out=p)
+
+        # gamma = <p,p>
+        gamma = np.dot(p.ravel(), p.ravel())
+
+        for i in range(its):
+            # w = W * p
+            W.FP(p, out=w)
+
+            # alpha = gamma / <w,w>
+            alpha = gamma / np.dot(w.ravel(), w.ravel())
+
+            # v += alpha * p
+            z[:] = p
+            z *= alpha
+            v += z
+
+            # r -= alpha * w
+            w *= -alpha;
+            r += w
+
+            # z = W' * r
+            W.BP(r, out=z)
+
+            # beta = <z,z> / gamma
+            newgamma = np.dot(z.ravel(), z.ravel())
+            beta = newgamma / gamma
+
+            # gamma = <z,z>
+            gamma = newgamma
+
+            # p = z + beta * p
+            p *= beta
+            p += z
+
-- 
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