You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: PBCH_decoder.m
    path of file: ./repos/polar-3gpp-matlab
    
    the code of the file until where you have to start completion: function a_hat = PBCH_decoder(f_tilde, A, L, min_sum, a_tilde)
% PCBH_DECODER Polar decoder for the Public Broadcast Channel (PBCH) of 3GPP New Radio, as
% defined in Section 7.1 of TS38.212. Implements the Cyclic Redudancy
% Check (CRC) attachment of Section 7.1.3, the channel coding of Section 7.1.4
% and the rate matching of Section 7.1.5. Note that this code does not
% implement the payload generation of Section 7.1.1 or the scrambling of
% Section 7.1.2.
%   a_hat = PBCH_DECODER(f_tilde, A, L, min_sum, a_tilde) decodes the encoded LLR sequence 
%   f_tilde, in order to obtain the recovered information bit sequence 
%   a_hat.
%
%   f_tilde should be a real row vector comprising 864 Logarithmic
%   Likelihood Ratios (LLRS), each having a value obtained as LLR =
%   ln(P(bit=0)/P(bit=1)). The first LLR corresponds to f_0 from Section 
%   7.1.5 of TS38.212, while the last LLR corresponds to 
%   f_E-1.
%
%   A should be 32. It specifies the number of bits in the
%   information bit sequence.
%
%   L should be a scalar integer. It specifies the list size to use during
%   Successive Cancellation List (SCL) decoding.
%
%   min_sum shoular be a scalar logical. If it is true, then the SCL
%   decoding process will be completed using the min-sum approximation.
%   Otherwise, the log-sum-product will be used. The log-sum-product gives
%   better error correction capability than the min-sum, but it has higher
%   complexity.
%

    
function a_hat = PBCH_decoder(f_tilde, A, L, min_sum, a_tilde)
% PCBH_DECODER Polar decoder for the Public Broadcast Channel (PBCH) of 3GPP New Radio, as
% defined in Section 7.1 of TS38.212. Implements the Cyclic Redudancy
% Check (CRC) attachment of Section 7.1.3, the channel coding of Section 7.1.4
% and the rate matching of Section 7.1.5. Note that this code does not
% implement the payload generation of Section 7.1.1 or the scrambling of
% Section 7.1.2.
%   a_hat = PBCH_DECODER(f_tilde, A, L, min_sum, a_tilde) decodes the encoded LLR sequence 
%   f_tilde, in order to obtain the recovered information bit sequence 
%   a_hat.
%
%   f_tilde should be a real row vector comprising 864 Logarithmic
%   Likelihood Ratios (LLRS), each having a value obtained as LLR =
%   ln(P(bit=0)/P(bit=1)). The first LLR corresponds to f_0 from Section 
%   7.1.5 of TS38.212, while the last LLR corresponds to 
%   f_E-1.
%
%   A should be 32. It specifies the number of bits in the
%   information bit sequence.
%
%   L should be a scalar integer. It specifies the list size to use during
%   Successive Cancellation List (SCL) decoding.
%
%   min_sum shoular be a scalar logical. If it is true, then the SCL
%   decoding process will be completed using the min-sum approximation.
%   Otherwise, the log-sum-product will be used. The log-sum-product gives
%   better error correction capability than the min-sum, but it has higher
%   complexity.
%
%   a_tilde should be a row vector comprising 32 elements. Elements having
%   the value 0 or 1 indicate that the receiver has prior knowledge that
%   the corresponding information bit has the corresponding value. Elements
%   having any other value indicate that the receiver does not have prior
%   knowledge of the value of the corresponding information bit. This
%   parameter can be omitted, in which case it will be assumed that the
%   receiver has no prior knowledge about the value of any of the
%   information bits. Note that this code does not perform the 
%   scrambling of Section 7.1.1 in TS38.212 V1.1.2, since this depend