diff options
Diffstat (limited to 'gr-trellis/src/lib/trellis_viterbi_combined_i.cc')
| -rw-r--r-- | gr-trellis/src/lib/trellis_viterbi_combined_i.cc | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/gr-trellis/src/lib/trellis_viterbi_combined_i.cc b/gr-trellis/src/lib/trellis_viterbi_combined_i.cc new file mode 100644 index 000000000..b415f064e --- /dev/null +++ b/gr-trellis/src/lib/trellis_viterbi_combined_i.cc @@ -0,0 +1,182 @@ +/* -*- c++ -*- */ +/* + * Copyright 2004 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * GNU Radio is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <trellis_viterbi_combined_i.h> +#include <gr_io_signature.h> +#include <assert.h> +#include <iostream> + +static const float INF = 1.0e9; + +trellis_viterbi_combined_i_sptr +trellis_make_viterbi_combined_i ( + const fsm &FSM, + const int D, + const std::vector<float> &TABLE, + const int K, + const int S0, + const int SK, + const trellis_metric_type_t TYPE) +{ + return trellis_viterbi_combined_i_sptr (new trellis_viterbi_combined_i (FSM,D,TABLE,K,S0,SK,TYPE)); +} + +trellis_viterbi_combined_i::trellis_viterbi_combined_i ( + const fsm &FSM, + const int D, + const std::vector<float> &TABLE, + const int K, + const int S0, + const int SK, + const trellis_metric_type_t TYPE) + : gr_block ("viterbi_combined_i", + gr_make_io_signature (1, -1, sizeof (float)), + gr_make_io_signature (1, -1, sizeof (int))), + d_FSM (FSM), + d_D (D), + d_TABLE (TABLE), + d_K (K), + d_S0 (S0), + d_SK (SK), + d_TYPE (TYPE), + d_trace(FSM.S()*K) +{ + set_relative_rate (1.0 / ((double) d_D)); + set_output_multiple (d_K); +} + + +void +trellis_viterbi_combined_i::forecast (int noutput_items, gr_vector_int &ninput_items_required) +{ + assert (noutput_items % d_K == 0); + int input_required = d_D * noutput_items ; + unsigned ninputs = ninput_items_required.size(); + for (unsigned int i = 0; i < ninputs; i++) { + ninput_items_required[i] = input_required; + } +} + + + + +void viterbi_algorithm_combined(const int I, const int S, const int O, + const std::vector<int> &NS, + const std::vector<int> &OS, + const std::vector<int> &PS, + const std::vector<int> &PI, + const int D, + const std::vector<float> &TABLE, + const int K, + const int S0,const int SK, + const trellis_metric_type_t TYPE, + const float *in, int *out, + std::vector<int> &trace) +{ + std::vector<float> alpha(S*2); + float *metric = new float[O]; + int alphai; + float norm,mm,minm; + int minmi; + int st; + + if(S0<0) { // initial state not specified + for(int i=0;i<S;i++) alpha[0*S+i]=0; + } + else { + for(int i=0;i<S;i++) alpha[0*S+i]=INF; + alpha[0*S+S0]=0.0; + } + + alphai=0; + for(int k=0;k<K;k++) { + calc_metric_f(O, D, TABLE, &(in[k*D]), metric,TYPE); // calc metrics + norm=INF; + for(int j=0;j<S;j++) { // for each next state do ACS + minm=INF; + minmi=0; + for(int i=0;i<I;i++) { + int i0 = j*I+i; + if((mm=alpha[alphai*S+PS[i0]]+metric[OS[PS[i0]*I+PI[i0]]])<minm) + minm=mm,minmi=i; + } + trace[k*S+j]=minmi; + alpha[((alphai+1)%2)*S+j]=minm; + if(minm<norm) norm=minm; + } + for(int j=0;j<S;j++) + alpha[((alphai+1)%2)*S+j]-=norm; // normalize total metrics so they do not explode + alphai=(alphai+1)%2; + } + + if(SK<0) { // final state not specified + minm=INF; + minmi=0; + for(int i=0;i<S;i++) + if((mm=trace[(K-1)*S+i])<minm) minm=mm,minmi=i; + st=minmi; + } + else { + st=SK; + } + + for(int k=K-1;k>=0;k--) { // traceback + int i0=st*I+trace[k*S+st]; + out[k]= (int) PI[i0]; + st=PS[i0]; + } + + delete [] metric; + +} + + + + + + +int +trellis_viterbi_combined_i::general_work (int noutput_items, + gr_vector_int &ninput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items) +{ + assert (input_items.size() == output_items.size()); + int nstreams = input_items.size(); + assert (noutput_items % d_K == 0); + int nblocks = noutput_items / d_K; + + for (int m=0;m<nstreams;m++) { + const float *in = (const float *) input_items[m]; + int *out = (int *) output_items[m]; + for (int n=0;n<nblocks;n++) { + viterbi_algorithm_combined(d_FSM.I(),d_FSM.S(),d_FSM.O(),d_FSM.NS(),d_FSM.OS(),d_FSM.PS(),d_FSM.PI(),d_D,d_TABLE,d_K,d_S0,d_SK,d_TYPE,&(in[n*d_K*d_D]),&(out[n*d_K]),d_trace); + } + } + + consume_each (d_D * noutput_items ); + return noutput_items; +} |