ctc_theano.py 文件源码

def _remove_adjdup(x):
        """
        Remove adjacent duplicate items of a vector
        x: vector
        return a vector with adjacent duplicate items removed, for example [1,2,2,2,3,3,4] -> [1,2,3,4]
        """
        def update(x, nondup, idx):
            nondup = tensor.switch(tensor.eq(nondup[idx], x), nondup, tensor.set_subtensor(nondup[idx + 1], x))  # tensor.switch is much faster than ifelse
            idx = tensor.switch(tensor.eq(nondup[idx], x), idx, idx + 1)
            return nondup, idx
        nondup = x
        idx = tensor.as_tensor_variable(0)
        idx = tensor.cast(idx, 'int32')
        result, updates = theano.scan(fn = update, sequences=x, outputs_info=[nondup, idx], name='remove_adjdup')
        nondup = result[0][-1]
        idx = result[1][-1]
        return nondup[0:idx+1]