scripts init

scripts/commpy/channelcoding/interleavers.py

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+
+
+# Authors: Veeresh Taranalli <veeresht@gmail.com>
+# License: BSD 3-Clause
+
+""" Interleavers and De-interleavers """
+
+from numpy import array, arange, zeros
+from numpy.random import mtrand
+
+__all__ = ['RandInterlv']
+
+class _Interleaver:
+
+    def interlv(self, in_array):
+        """ Interleave input array using the specific interleaver.
+
+        Parameters
+        ----------
+        in_array : 1D ndarray of ints
+            Input data to be interleaved.
+
+        Returns
+        -------
+        out_array : 1D ndarray of ints
+            Interleaved output data.
+
+        """
+        out_array = array(map(lambda x: in_array[x], self.p_array))
+        return out_array
+
+    def deinterlv(self, in_array):
+        """ De-interleave input array using the specific interleaver.
+
+        Parameters
+        ----------
+        in_array : 1D ndarray of ints
+            Input data to be de-interleaved.
+
+        Returns
+        -------
+        out_array : 1D ndarray of ints
+            De-interleaved output data.
+
+        """
+        out_array = zeros(len(in_array), in_array.dtype)
+        for index, element in enumerate(self.p_array):
+            out_array[element] = in_array[index]
+        return out_array
+
+class RandInterlv(_Interleaver):
+    """ Random Interleaver.
+
+    Parameters
+    ----------
+    length : int
+        Length of the interleaver.
+
+    seed : int
+        Seed to initialize the random number generator
+        which generates the random permutation for
+        interleaving.
+
+    Returns
+    -------
+    random_interleaver : RandInterlv object
+        A random interleaver object.
+
+    Note
+    ----
+    The random number generator is the
+    RandomState object from NumPy,
+    which uses the Mersenne Twister algorithm.
+
+    """
+    def __init__(self, length, seed):
+        rand_gen = mtrand.RandomState(seed)
+        self.p_array = rand_gen.permutation(arange(length))
+
+
+#class SRandInterlv(_Interleaver):
+
+
+#class QPPInterlv(_Interleaver):