% Author:  David Varodayan (varodayan@stanford.edu)% Date:    May 8, 2006function peg2lad( pegFile, ladFile )tic%loop until full rank H_square is generatedwhile 1    fid = fopen( pegFile, 'r' );    n = fscanf(fid, '%d', 1);    m = fscanf(fid, '%d', 1);    maxDegree = fscanf(fid, '%d', 1);    expansion = n./m;    H_square = zeros(n, n);    for i=1:m        oneLocations = fscanf(fid, '%d', maxDegree)';        oneLocations = oneLocations(find(oneLocations));        degree = length(oneLocations);        oneLocations = oneLocations(randperm(degree));        for j=1:expansion            locationSubset = oneLocations( round((j-1)./expansion.*degree)+1:round(j./expansion.*degree) );            H_square( (i-1).*expansion+j, locationSubset ) = 1;        end    end    fclose(fid);    H_square = H_square(:, randperm(n));    % check whether H_square is full rank in GF(2)    A = int8(H_square);    rank = 0;    for col=1:n        oneRows = find(A(:,col)==1);        if length(oneRows)>0            rank = rank+1;            for row=oneRows(length(oneRows):-1:1)'                A(row,col:n) = xor(A(row,col:n), A(oneRows(1),col:n));            end        end    end        toc    if rank==n        break;    endendclear AnumCodes = 65;period = 66;txSeq = [33 16 24 8 28 12 20 4 30 14 22 6 26 10 18 2 31 15 23 7 27 11 19 3 29 13 21 5 25 9 17 1 32];txSeq = reshape([txSeq+33; txSeq], 1, 66);% txSeq is the order in which samples of accumulated syndrome are transmittedfid = fopen(ladFile, 'w');fprintf(fid, '%d ', [numCodes n sum(sum(H_square)) period]);jc = [0 full(cumsum(sum(H_square)))];fprintf(fid, '\n');fprintf(fid, '%d ', jc);for code=period-numCodes+1:period    H = zeros(n/period*code, n);    row = 1;    txSubseq = mod(txSeq(1:code), period);    for row_square=1:n        H(row, :) = H(row, :) + H_square(row_square, :);        row = row + ismember( mod(row_square, period), txSubseq );    end    fprintf(fid, '\n');    fprintf(fid, '%d ', code);    fprintf(fid, '\n');    fprintf(fid, '%d ', sort(txSeq(1:code))-1);    ir = mod(find(H)-1, n/period*code);    fprintf(fid, '\n');    fprintf(fid, '%d ', ir);    code    toc        clear Hendfclose(fid);