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class IndexTransformDecimationInFrequency(object):
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"""docstring for IndexTransformDecimationInFrequency"""
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def __init__(self, N):
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super(IndexTransformDecimationInFrequency, self).__init__()
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self.N = N
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self.new_k = range(self.N)
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self.build_index_vector()
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print 'new_k = ', self.new_k
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def reverse_order(self, sequence):
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old_sequence = sequence[:]
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for i in (range(len(sequence))):
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a = sequence[ i ];
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sequence[ i ] = old_sequence[ self.new_k[i] ]
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def build_index_vector(self):
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if self.N == 8: # 2^3 => 3 bits
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for indice in range(self.N):
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b = '{:03b}'.format(indice)
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b = b[::-1]
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self.new_k[indice] = int(b, 2)
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elif self.N == 16: # 2^4 => 4 bits
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for indice in range(self.N):
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b = '{:04b}'.format(indice)
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b = b[::-1]
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self.new_k[indice] = int(b, 2)
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elif self.N == 32: # 2^5 => 5 bits
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for indice in range(self.N):
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b = '{:05b}'.format(indice)
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b = b[::-1]
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self.new_k[indice] = int(b, 2)
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elif self.N == 256: # 2^8 => 8 bits
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for indice in range(self.N):
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b = '{:08b}'.format(indice)
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b = b[::-1]
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self.new_k[indice] = int(b, 2)
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else:
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print'error, N = ', self.N, ' is not supported by the index_transform function'
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if __name__ == "__main__":
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x = range(8)
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indexTransformDecimationInFrequency = IndexTransformDecimationInFrequency(len(x))
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print 'x ', x
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indexTransformDecimationInFrequency.reverse_order(x)
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print 'x rearranged ', x
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y = x
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indexTransformDecimationInFrequency.reverse_order(y)
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print 'y ', y
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x = range(16)
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indexTransformDecimationInFrequency = IndexTransformDecimationInFrequency(len(x))
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print 'x ', x
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indexTransformDecimationInFrequency.reverse_order(x)
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print 'x rearranged ', x
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y = x
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indexTransformDecimationInFrequency.reverse_order(y)
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print 'y ', y
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