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: reorder_matrix.m
    path of file: ./repos/CanlabCore/CanlabCore/External/2019_03_03_BCT
    
    the code of the file until where you have to start completion: function [Mreordered,Mindices,cost] = reorder_matrix(M1,cost,flag)
% REORDER_MATRIX         Matrix reordering for visualization
%
%   [Mreordered,Mindices,cost] = reorder_matrix(M1,cost,flag)
%
%   This function rearranges the nodes in matrix M1 such that the matrix
%   elements are squeezed along the main diagonal.  The function uses a
%   version of simulated annealing. 
%
%   Inputs:     M1             = connection matrix (weighted or binary, 
%                                directed or undirected)
%               cost           = 'line' or 'circ', for shape of lattice
%                                cost (linear or ring lattice)
%
%               Mreordered     = reordered connection matrix

    
function [Mreordered,Mindices,cost] = reorder_matrix(M1,cost,flag)
% REORDER_MATRIX         Matrix reordering for visualization
%
%   [Mreordered,Mindices,cost] = reorder_matrix(M1,cost,flag)
%
%   This function rearranges the nodes in matrix M1 such that the matrix
%   elements are squeezed along the main diagonal.  The function uses a
%   version of simulated annealing. 
%
%   Inputs:     M1             = connection matrix (weighted or binary, 
%                                directed or undirected)
%               cost           = 'line' or 'circ', for shape of lattice
%                                cost (linear or ring lattice)
%
%               Mreordered     = reordered connection matrix
%               Mindices       = reordered indices
%               cost           = distance between M1 and Mreordered
%
%   Note that in general, the outcome will depend