idx_file.txt is not effectively updated with the current epoch.

[cridin1]

When saving the idx_file.txt that keeps track of epochs already done, it is always passed 0 as the saved epoch:

idx_file = os.path.join(last_output_dir, 'idx_file.txt')
with open(idx_file, 'w', encoding='utf-8') as idxf:
    idxf.write(str(0) + '\n')