204 lines
8.5 KiB
C++
204 lines
8.5 KiB
C++
/*
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* Copyright (c) 2015 Cryptonomex, Inc., and contributors.
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*
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* The MIT License
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <graphene/chain/protocol/asset.hpp>
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#include <boost/rational.hpp>
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#include <boost/multiprecision/cpp_int.hpp>
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namespace graphene { namespace chain {
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typedef boost::multiprecision::uint128_t uint128_t;
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typedef boost::multiprecision::int128_t int128_t;
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bool operator == ( const price& a, const price& b )
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{
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if( std::tie( a.base.asset_id, a.quote.asset_id ) != std::tie( b.base.asset_id, b.quote.asset_id ) )
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return false;
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const auto amult = uint128_t( b.quote.amount.value ) * a.base.amount.value;
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const auto bmult = uint128_t( a.quote.amount.value ) * b.base.amount.value;
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return amult == bmult;
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}
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bool operator < ( const price& a, const price& b )
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{
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if( a.base.asset_id < b.base.asset_id ) return true;
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if( a.base.asset_id > b.base.asset_id ) return false;
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if( a.quote.asset_id < b.quote.asset_id ) return true;
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if( a.quote.asset_id > b.quote.asset_id ) return false;
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const auto amult = uint128_t( b.quote.amount.value ) * a.base.amount.value;
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const auto bmult = uint128_t( a.quote.amount.value ) * b.base.amount.value;
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return amult < bmult;
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}
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bool operator <= ( const price& a, const price& b )
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{
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return (a == b) || (a < b);
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}
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bool operator != ( const price& a, const price& b )
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{
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return !(a == b);
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}
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bool operator > ( const price& a, const price& b )
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{
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return !(a <= b);
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}
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bool operator >= ( const price& a, const price& b )
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{
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return !(a < b);
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}
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asset operator * ( const asset& a, const price& b )
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{
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if( a.asset_id == b.base.asset_id )
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{
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FC_ASSERT( b.base.amount.value > 0 );
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uint128_t result = (uint128_t(a.amount.value) * b.quote.amount.value)/b.base.amount.value;
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FC_ASSERT( result <= GRAPHENE_MAX_SHARE_SUPPLY );
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return asset( result.convert_to<int64_t>(), b.quote.asset_id );
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}
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else if( a.asset_id == b.quote.asset_id )
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{
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FC_ASSERT( b.quote.amount.value > 0 );
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uint128_t result = (uint128_t(a.amount.value) * b.base.amount.value)/b.quote.amount.value;
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FC_ASSERT( result <= GRAPHENE_MAX_SHARE_SUPPLY );
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return asset( result.convert_to<int64_t>(), b.base.asset_id );
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}
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FC_THROW_EXCEPTION( fc::assert_exception, "invalid asset * price", ("asset",a)("price",b) );
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}
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price operator / ( const asset& base, const asset& quote )
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{ try {
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FC_ASSERT( base.asset_id != quote.asset_id );
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return price{base,quote};
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} FC_CAPTURE_AND_RETHROW( (base)(quote) ) }
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price price::max( asset_id_type base, asset_id_type quote ) { return asset( share_type(GRAPHENE_MAX_SHARE_SUPPLY), base ) / asset( share_type(1), quote); }
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price price::min( asset_id_type base, asset_id_type quote ) { return asset( 1, base ) / asset( GRAPHENE_MAX_SHARE_SUPPLY, quote); }
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/**
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* The black swan price is defined as debt/collateral, we want to perform a margin call
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* before debt == collateral. Given a debt/collateral ratio of 1 USD / CORE and
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* a maintenance collateral requirement of 2x we can define the call price to be
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* 2 USD / CORE.
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*
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* This method divides the collateral by the maintenance collateral ratio to derive
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* a call price for the given black swan ratio.
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*
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* There exists some cases where the debt and collateral values are so small that
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* dividing by the collateral ratio will result in a 0 price or really poor
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* rounding errors. No matter what the collateral part of the price ratio can
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* never go to 0 and the debt can never go more than GRAPHENE_MAX_SHARE_SUPPLY
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*
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* CR * DEBT/COLLAT or DEBT/(COLLAT/CR)
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*/
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price price::call_price( const asset& debt, const asset& collateral, uint16_t collateral_ratio)
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{ try {
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//wdump((debt)(collateral)(collateral_ratio));
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boost::rational<int128_t> swan(debt.amount.value,collateral.amount.value);
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boost::rational<int128_t> ratio( collateral_ratio, GRAPHENE_COLLATERAL_RATIO_DENOM );
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auto cp = swan * ratio;
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while( cp.numerator() > GRAPHENE_MAX_SHARE_SUPPLY || cp.denominator() > GRAPHENE_MAX_SHARE_SUPPLY )
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cp = boost::rational<int128_t>( (cp.numerator() >> 1)+1, (cp.denominator() >> 1)+1 );
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return ~(asset( cp.numerator().convert_to<int64_t>(), debt.asset_id ) / asset( cp.denominator().convert_to<int64_t>(), collateral.asset_id ));
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} FC_CAPTURE_AND_RETHROW( (debt)(collateral)(collateral_ratio) ) }
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bool price::is_null() const { return *this == price(); }
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void price::validate() const
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{ try {
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FC_ASSERT( base.amount > share_type(0) );
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FC_ASSERT( quote.amount > share_type(0) );
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FC_ASSERT( base.asset_id != quote.asset_id );
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} FC_CAPTURE_AND_RETHROW( (base)(quote) ) }
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void price_feed::validate() const
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{ try {
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if( !settlement_price.is_null() )
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settlement_price.validate();
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FC_ASSERT( maximum_short_squeeze_ratio >= GRAPHENE_MIN_COLLATERAL_RATIO );
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FC_ASSERT( maximum_short_squeeze_ratio <= GRAPHENE_MAX_COLLATERAL_RATIO );
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FC_ASSERT( maintenance_collateral_ratio >= GRAPHENE_MIN_COLLATERAL_RATIO );
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FC_ASSERT( maintenance_collateral_ratio <= GRAPHENE_MAX_COLLATERAL_RATIO );
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max_short_squeeze_price(); // make sure that it doesn't overflow
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//FC_ASSERT( maintenance_collateral_ratio >= maximum_short_squeeze_ratio );
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} FC_CAPTURE_AND_RETHROW( (*this) ) }
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bool price_feed::is_for( asset_id_type asset_id ) const
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{
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try
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{
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if( !settlement_price.is_null() )
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return (settlement_price.base.asset_id == asset_id);
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if( !core_exchange_rate.is_null() )
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return (core_exchange_rate.base.asset_id == asset_id);
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// (null, null) is valid for any feed
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return true;
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}
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FC_CAPTURE_AND_RETHROW( (*this) )
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}
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price price_feed::max_short_squeeze_price()const
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{
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boost::rational<int128_t> sp( settlement_price.base.amount.value, settlement_price.quote.amount.value ); //debt.amount.value,collateral.amount.value);
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boost::rational<int128_t> ratio( GRAPHENE_COLLATERAL_RATIO_DENOM, maximum_short_squeeze_ratio );
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auto cp = sp * ratio;
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while( cp.numerator() > GRAPHENE_MAX_SHARE_SUPPLY || cp.denominator() > GRAPHENE_MAX_SHARE_SUPPLY )
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cp = boost::rational<int128_t>( (cp.numerator() >> 1)+(cp.numerator()&1), (cp.denominator() >> 1)+(cp.denominator()&1) );
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return (asset( cp.numerator().convert_to<int64_t>(), settlement_price.base.asset_id ) / asset( cp.denominator().convert_to<int64_t>(), settlement_price.quote.asset_id ));
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}
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// compile-time table of powers of 10 using template metaprogramming
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template< int N >
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struct p10
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{
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static const int64_t v = 10 * p10<N-1>::v;
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};
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template<>
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struct p10<0>
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{
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static const int64_t v = 1;
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};
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const int64_t scaled_precision_lut[19] =
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{
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p10< 0 >::v, p10< 1 >::v, p10< 2 >::v, p10< 3 >::v,
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p10< 4 >::v, p10< 5 >::v, p10< 6 >::v, p10< 7 >::v,
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p10< 8 >::v, p10< 9 >::v, p10< 10 >::v, p10< 11 >::v,
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p10< 12 >::v, p10< 13 >::v, p10< 14 >::v, p10< 15 >::v,
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p10< 16 >::v, p10< 17 >::v, p10< 18 >::v
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};
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} } // graphene::chain
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