Max index filter block

max_index.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
# Copyright 2014 Marcus Müller.
# 
# This 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.
# 
# This software 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 this software; 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 max_index(gr.sync_block):
    """
	finds the maximum index in a vector and outputs it on the output stream
    """
    def __init__(self, vlen, dtype=numpy.float32):
        gr.sync_block.__init__(self,
            name="max_index",
            in_sig=[(numpy.dtype(dtype),vlen)],
            out_sig=[numpy.short])


    def work(self, input_items, output_items):
        in0 = input_items[0]
        out = output_items[0]
        out[:] = [ numpy.argmax(vector) for vector in in0 ]
        return len(output_items[0])

qa_max_index.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
# Copyright 2014 Marcus Müller.
# 
# This 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.
# 
# This software 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 this software; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
# 

from gnuradio import gr, gr_unittest
from gnuradio import blocks
from max_index import max_index
import numpy

class qa_max_index (gr_unittest.TestCase):

    def setUp (self):
        self.tb = gr.top_block ()

    def tearDown (self):
        self.tb = None

    def test_max_idx (self):
        # set up fg
        N = 100
        self.data = numpy.identity(N).ravel()
        self.src = blocks.vector_source_f(self.data, vlen=N, repeat=False)
        self.sink = blocks.vector_sink_s()
        self.maxarg = max_index(N)
        self.tb.connect(self.src, self.maxarg, self.sink)
        self.tb.run ()
        self.tb.wait()
        testdata = self.sink.data()
        self.assertTupleEqual(testdata, tuple(range(N)))
        print testdata
        # check data


if __name__ == '__main__':
    gr_unittest.run(qa_max_index, "qa_max_index.xml")