Tim O'Shea
264 lines
7.6 KiB
C++
264 lines
7.6 KiB
C++
/*
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* Copyright (C) 2013 Bastian Bloessl <bloessl@ccs-labs.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <gnuradio/ieee802_11/ofdm_sync_long.h>
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#include <gnuradio/io_signature.h>
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#include <gnuradio/filter/fir_filter.h>
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#include <gnuradio/fft/fft.h>
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#include <list>
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#include <tuple>
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#include <iostream>
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using namespace gr::ieee802_11;
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class ofdm_sync_long_impl : public ofdm_sync_long {
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#define dout d_debug && std::cout
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public:
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ofdm_sync_long_impl(unsigned int sync_lenght, unsigned int freq_est, bool debug) : gr::block("ofdm_sync_long",
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gr::io_signature::make2(2, 2, sizeof(gr_complex), sizeof(gr_complex)),
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gr::io_signature::make(1, 1, sizeof(gr_complex))),
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d_debug(debug),
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d_offset(0),
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d_freq_est(0),
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d_state(SYNC),
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SYNC_LENGTH(sync_lenght),
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FREQ_EST(freq_est) {
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set_tag_propagation_policy(gr::block::TPP_DONT);
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d_fir = new gr::filter::kernel::fir_filter_ccc(1, LONG);
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d_correlation = gr::fft::malloc_complex(8192);
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}
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~ofdm_sync_long_impl(){
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delete d_fir;
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gr::fft::free(d_correlation);
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}
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int general_work (int noutput, gr_vector_int& ninput_items,
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gr_vector_const_void_star& input_items,
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gr_vector_void_star& output_items) {
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const gr_complex *in = (const gr_complex*)input_items[0];
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const gr_complex *in_delayed = (const gr_complex*)input_items[1];
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gr_complex *out = (gr_complex*)output_items[0];
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dout << "LONG ninput[0] " << ninput_items[0] << " ninput[1] " <<
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ninput_items[1] << " noutput " << noutput <<
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" state " << d_state << std::endl;
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int ninput = std::min(ninput_items[0], ninput_items[1]);
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const unsigned int nread = nitems_read(0);
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get_tags_in_range(d_tags, 0, nread, nread + ninput);
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if (d_tags.size()) {
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std::sort(d_tags.begin(), d_tags.end(), gr::tag_t::offset_compare);
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const gr::tag_t &tag = d_tags.front();
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const uint64_t offset = tag.offset;
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if(offset > nread) {
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ninput = offset - nread;
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} else {
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if(d_state == COPY) {
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d_state = RESET;
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}
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}
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}
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int i = 0;
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int o = 0;
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switch(d_state) {
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case SYNC:
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d_fir->filterN(d_correlation, in, std::min(SYNC_LENGTH, std::max(ninput - 63, 0)));
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while(i + 63 < ninput) {
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if(d_offset < FREQ_EST) {
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d_freq_est += in[i] * conj(in[i + 16]);
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}
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d_cor.push_back(std::tuple<double, int>(abs(d_correlation[i]), d_offset));
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i++;
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d_offset++;
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if(d_offset == SYNC_LENGTH) {
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search_frame_start();
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d_offset = 0;
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d_state = COPY;
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break;
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}
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}
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break;
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case COPY:
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while(i < ninput) {
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int rel = d_offset - d_frame_start;
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if( (rel >= 0) && (rel % 80 > 15)) {
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if(o >= noutput) {
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break;
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}
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if(rel == 16) {
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assert(o == 0);
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add_item_tag(0, nitems_written(0) + o,
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pmt::string_to_symbol("ofdm_start"),
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pmt::PMT_T,
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pmt::string_to_symbol(name()));
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}
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out[o] = in_delayed[i] * exp(gr_complex(0, d_offset * arg(d_freq_est) / 16));
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o++;
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}
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i++;
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d_offset++;
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}
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break;
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case RESET:
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while(o < noutput) {
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int rel = (d_offset - d_frame_start) % 80;
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if(!rel) {
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d_offset = 0;
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d_freq_est = gr_complex(0, 0);
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d_state = SYNC;
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break;
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} else if(rel > 15) {
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out[o] = 0;
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o++;
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}
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d_offset++;
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}
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break;
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default:
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assert(false);
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break;
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}
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dout << "produced : " << o << " consumed: " << i << std::endl;
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consume(0, i);
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consume(1, i);
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return o;
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}
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void forecast (int noutput_items, gr_vector_int &ninput_items_required) {
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if(d_state == SYNC) {
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ninput_items_required[0] = 64;
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ninput_items_required[1] = 64;
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} else {
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ninput_items_required[0] = noutput_items;
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ninput_items_required[1] = noutput_items;
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}
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0 && dout << "LONG forecast noutput_items: " << noutput_items
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<< " state: " << d_state
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<< " req[0] " << ninput_items_required[0]
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<< " req[1] " << ninput_items_required[1]
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<< std::endl;
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}
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void search_frame_start() {
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assert(d_cor.size() == SYNC_LENGTH);
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d_cor.sort();
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d_cor.reverse();
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std::list<std::tuple<double, int>>::iterator it = d_cor.begin();
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int m1 = std::get<1>(*it);
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it++;
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int m2 = std::get<1>(*it);
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it++;
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int m3 = std::get<1>(*it);
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int m = std::max(m1, std::max(m2, m3));
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d_frame_start = m + 64;
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dout << "d_frame_start " << d_frame_start << std::endl;
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dout << "peaks " << m1 << " " << m2 << " " << m3 << std::endl;
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//for(it = d_cor.begin(); it != d_cor.end(); it++) {
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//std::cout << std::get<0>(*it) << " " << std::get<1>(*it) << std::endl;
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//}
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d_cor.clear();
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}
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private:
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enum {SYNC, COPY, RESET} d_state;
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int d_offset;
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int d_frame_start;
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gr_complex d_freq_est;
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gr_complex *d_correlation;
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std::list<std::tuple<double, int>> d_cor;
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std::vector<gr::tag_t> d_tags;
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gr::filter::kernel::fir_filter_ccc *d_fir;
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const bool d_debug;
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const int SYNC_LENGTH;
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const int FREQ_EST;
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static const std::vector<gr_complex> LONG;
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};
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ofdm_sync_long::sptr
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ofdm_sync_long::make(unsigned int sync_length, unsigned int freq_est, bool debug) {
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return gnuradio::get_initial_sptr(new ofdm_sync_long_impl(sync_length, freq_est, debug));
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}
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const std::vector<gr_complex> ofdm_sync_long_impl::LONG = {
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gr_complex( -0.04097-0.9626011), gr_complex( 0.3179976-0.8892635), gr_complex( 0.7746551+0.6623833),
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gr_complex( 0.1688942+0.2230874), gr_complex( 0.4785908-0.7016541), gr_complex( -0.9210497-0.441444),
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gr_complex( -0.3065277-0.8493673), gr_complex( 0.7803301-0.2071068), gr_complex( 0.4267019+0.0326106),
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gr_complex( 0.0079118-0.9200371), gr_complex( -1.094439-0.379038), gr_complex( 0.1958068-0.4682544),
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gr_complex( 0.4693501-0.119512), gr_complex( -0.179866+1.285259), gr_complex( 0.9539127-0.0327648),
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gr_complex( 0.5-0.5), gr_complex( 0.2953435+0.7867532), gr_complex( -0.4576508+0.3143887),
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gr_complex( -1.050101+0.521818), gr_complex( 0.6577466+0.7388524), gr_complex( 0.5564548+0.1129757),
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gr_complex( -0.4824808+0.650289), gr_complex( -0.451641-0.1744314), gr_complex( -0.28033-1.207107),
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gr_complex( -0.9750961-0.1325297), gr_complex( -1.018595-0.164011), gr_complex( 0.6005896-0.5923234),
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gr_complex( -0.0224476+0.4301941), gr_complex( -0.7351004+0.9210297), gr_complex( 0.7337324+0.8469733),
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gr_complex( 0.0982767+0.7807964), gr_complex( -1.25+0), gr_complex( 0.0982767-0.7807964),
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gr_complex( 0.7337324-0.8469733), gr_complex( -0.7351004-0.9210297), gr_complex( -0.0224476-0.4301941),
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gr_complex( 0.6005896+0.5923234), gr_complex( -1.018595+0.164011), gr_complex( -0.9750961+0.1325297),
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gr_complex( -0.28033+1.207107), gr_complex( -0.451641+0.1744314), gr_complex( -0.4824808-0.650289),
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gr_complex( 0.5564548-0.1129757), gr_complex( 0.6577466-0.7388524), gr_complex( -1.050101-0.521818),
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gr_complex( -0.4576508-0.3143887), gr_complex( 0.2953435-0.7867532), gr_complex( 0.5+0.5),
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gr_complex( 0.9539127+0.0327648), gr_complex( -0.179866-1.285259), gr_complex( 0.4693501+0.119512),
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gr_complex( 0.1958068+0.4682544), gr_complex( -1.094439+0.379038), gr_complex( 0.0079118+0.9200371),
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gr_complex( 0.4267019-0.0326106), gr_complex( 0.7803301+0.2071068), gr_complex( -0.3065277+0.8493673),
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gr_complex( -0.9210497+0.441444), gr_complex( 0.4785908+0.7016541), gr_complex( 0.1688942-0.2230874),
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gr_complex( 0.7746551-0.6623833), gr_complex( 0.3179976+0.8892635), gr_complex( -0.04097+0.9626011),
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gr_complex( 1.25+0)};
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