On the capability of the Harada-Kobayashi algorithm in finding fix-free codewords

The capability of the Harada-Kobayashi algorithm in finding fix-free codewords is examined. For n les 30, it is observed that this algorithm finds fix-free codewords for more than 99 percent of codelength vectors with Kraft sum 3/4. Moreover, it will find fix-free codewords for all codelength vectors with Kraft sum 11/16 and n les 30. A simple variation of the Harada-Kobayashi algorithm succeeds in more than 99 percent of its failures.