Method open_loop_nbest_pitch

Find the n-best pitch in Open Loop. @param sw @param swIdx @param start @param end @param len @param pitch @param gain @param N

(final float[] sw,
                                              final int swIdx,
                                              final int start,
                                              final int end,
                                              final int len,
                                              final int[] pitch,
                                              final float[] gain,
                                              final int N)