% Loads a beamlet batch into a cell array of sparse matrices
function beamlets = open_beamlet_batch(batchname)

fid = fopen(batchname,'rb');
Nbeamlets = fread(fid,1,'int');  % number of beamlets in this file

beamlets = cell(1,Nbeamlets);

for k=1:Nbeamlets
    beamlets{k}.num = fread(fid,1,'int');
    beamlets{k}.x_count = fread(fid,1,'int');
    beamlets{k}.y_count = fread(fid,1,'int');
    beamlets{k}.z_count = fread(fid,1,'int');
    Nind = fread(fid,1,'int');  % number of non-zero values
    beamlets{k}.non_zero_indices = fread(fid,Nind,'int=>int');
    beamlets{k}.non_zero_values = fread(fid,Nind,'float=>float');
    % add unity to the indices to convert them from C to Matlab style
    % indexing:
    beamlets{k}.non_zero_indices = beamlets{k}.non_zero_indices + 1;
end

fclose(fid);