Tiralabra is a project mainly written in C++, it's free.
Tiralabra
To try out stuff, compile bodlx.cpp with for example the following:
g++ bodlx.cpp -o bodlx -O2
and run with
./bodlx < testcase, for example ./bodlx < sudoku.9.in.escargot
Also to test with the conventional backtracking algorithm, please use backtracking.cpp in a similar manner.