4 files changed, 62 insertions, 0 deletions
diff --git a/gr-howto-write-a-block/python/CMakeLists.txt b/gr-howto-write-a-block/python/CMakeLists.txt
index d5fb19523..ac5531638 100644
--- a/gr-howto-write-a-block/python/CMakeLists.txt
+++ b/gr-howto-write-a-block/python/CMakeLists.txt
@@ -31,6 +31,7 @@ endif()
 GR_PYTHON_INSTALL(
     FILES
     __init__.py
+    square3_ff.py
     DESTINATION ${GR_PYTHON_DIR}/howto
 )
 
diff --git a/gr-howto-write-a-block/python/__init__.py b/gr-howto-write-a-block/python/__init__.py
index 2bd27cb31..6e5e1c147 100644
--- a/gr-howto-write-a-block/python/__init__.py
+++ b/gr-howto-write-a-block/python/__init__.py
@@ -25,6 +25,7 @@ description here (python/__init__.py).
 
 # import swig generated symbols into the howto namespace
 from howto_swig import *
+from square3_ff import square3_ff
 
 # import any pure python here
 #
diff --git a/gr-howto-write-a-block/python/qa_howto.py b/gr-howto-write-a-block/python/qa_howto.py
index 7321941d5..5e62fc890 100755
--- a/gr-howto-write-a-block/python/qa_howto.py
+++ b/gr-howto-write-a-block/python/qa_howto.py
@@ -22,6 +22,7 @@
 
 from gnuradio import gr, gr_unittest
 import howto_swig
+from square3_ff import square3_ff
 
 class qa_howto (gr_unittest.TestCase):
 
@@ -55,5 +56,17 @@ class qa_howto (gr_unittest.TestCase):
         result_data = dst.data ()
         self.assertFloatTuplesAlmostEqual (expected_result, result_data, 6)
 
+    def test_003_square3_ff (self):
+        src_data = (-3, 4, -5.5, 2, 3)
+        expected_result = (9, 16, 30.25, 4, 9)
+        src = gr.vector_source_f (src_data)
+        sqr = square3_ff ()
+        dst = gr.vector_sink_f ()
+        self.tb.connect (src, sqr)
+        self.tb.connect (sqr, dst)
+        self.tb.run ()
+        result_data = dst.data ()
+        self.assertFloatTuplesAlmostEqual (expected_result, result_data, 6)
+
 if __name__ == '__main__':
     gr_unittest.main ()
diff --git a/gr-howto-write-a-block/python/square3_ff.py b/gr-howto-write-a-block/python/square3_ff.py
new file mode 100644
index 000000000..df702734e
--- /dev/null
+++ b/gr-howto-write-a-block/python/square3_ff.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+#
+# Copyright 2013 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio 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, or (at your option)
+# any later version.
+#
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+import numpy
+from gnuradio import gr
+
+class square3_ff(gr.sync_block):
+    " Squaring block "
+    def __init__(self):
+        gr.sync_block.__init__(
+            self,
+            name = "square3_ff",
+            in_sig = [numpy.float32], # Input signature: 1 float at a time
+            out_sig = [numpy.float32], # Output signature: 1 float at a time
+        )
+
+    def work(self, input_items, output_items):
+        """ Notes:
+        - You must not forget the [:] at the output items, otherwise
+          stuff doesn't truly get copied to the output
+        - Both input_ and output_items[N] are numpy arrays, so you can
+          do fancy stuff like multiplying them elementwise
+        - noutput_items and ninput_items are implicit in the length of
+          output_items and input_items, respectively
+        """
+        output_items[0][:] = input_items[0] * input_items[0]
+        return len(output_items[0])
+