Refactor rewards calculations to use curve IDs in reward fund objects #…

…1051 #1052

libraries/app/database_api.cpp

@@ -1140,7 +1140,10 @@ void database_api::set_pending_payout( discussion& d )const
    {
       uint128_t vshares;
       if( my->_db.has_hardfork( STEEMIT_HARDFORK_0_17__774 ) )
-         vshares = steemit::chain::util::calculate_claims( d.net_rshares.value > 0 ? d.net_rshares.value : 0 , my->_db.get_reward_fund( my->_db.get_comment( d.author, d.permlink ) ) );
+      {
+         const auto& rf = my->_db.get_reward_fund( my->_db.get_comment( d.author, d.permlink ) );
+         vshares = d.net_rshares.value > 0 ? steemit::chain::util::calculate_claims( d.net_rshares.value, rf.author_reward_curve, rf.content_constant ) : 0;
+      }
       else
          vshares = steemit::chain::util::calculate_claims( d.net_rshares.value > 0 ? d.net_rshares.value : 0 );
 

libraries/chain/database.cpp

@@ -1482,8 +1482,14 @@ share_type database::cashout_comment_helper( util::comment_reward_context& ctx,
       {
          fill_comment_reward_context_local_state( ctx, comment );
 
-         const share_type reward = has_hardfork( STEEMIT_HARDFORK_0_17__774 ) ?
-            util::get_rshare_reward( ctx, get_reward_fund( comment ) ) : util::get_rshare_reward( ctx );
+         if( has_hardfork( STEEMIT_HARDFORK_0_17__774 ) )
+         {
+            const auto rf = get_reward_fund( comment );
+            ctx.reward_curve = rf.author_reward_curve;
+            ctx.content_constant = rf.content_constant;
+         }
+
+         const share_type reward = util::get_rshare_reward( ctx );
          uint128_t reward_tokens = uint128_t( reward.value );
 
          if( reward_tokens > 0 )
@@ -1639,7 +1645,7 @@ void database::process_comment_cashout()
          if( current->net_rshares > 0 )
          {
             const auto& rf = get_reward_fund( *current );
-            funds[ rf.id._id ].recent_claims += util::calculate_claims( current->net_rshares.value, rf );
+            funds[ rf.id._id ].recent_claims += util::calculate_claims( current->net_rshares.value, rf.author_reward_curve, rf.content_constant );
          }
 
          ++current;
@@ -3756,6 +3762,8 @@ void database::apply_hardfork( uint32_t hardfork )
 #ifndef IS_TEST_NET
                rfo.recent_claims = STEEMIT_HF_17_RECENT_CLAIMS;
 #endif
+               rfo.author_reward_curve = curve_id::quadratic;
+               rfo.curation_reward_curve = curve_id::quadratic_curation;
             });
 
             // As a shortcut in payout processing, we use the id as an array index.

libraries/chain/include/steemit/chain/steem_objects.hpp

@@ -249,6 +249,14 @@ namespace steemit { namespace chain {
          time_point_sec    effective_date;
    };
 
+   enum curve_id
+   {
+      quadratic,
+      quadratic_curation,
+      linear,
+      square_root
+   };
+
    class reward_fund_object : public object< reward_fund_object_type, reward_fund_object >
    {
       public:
@@ -268,6 +276,8 @@ namespace steemit { namespace chain {
          uint128_t               content_constant = 0;
          uint16_t                percent_curation_rewards = 0;
          uint16_t                percent_content_rewards = 0;
+         curve_id                author_reward_curve;
+         curve_id                curation_reward_curve;
    };
 
    struct by_price;
@@ -479,6 +489,8 @@ namespace steemit { namespace chain {
 #include <steemit/chain/comment_object.hpp>
 #include <steemit/chain/account_object.hpp>
 
+FC_REFLECT_ENUM( steemit::chain::curve_id,
+                  (quadratic)(quadratic_curation)(linear)(square_root))
 
 FC_REFLECT( steemit::chain::limit_order_object,
              (id)(created)(expiration)(seller)(orderid)(for_sale)(sell_price) )
@@ -524,5 +536,7 @@ FC_REFLECT( steemit::chain::reward_fund_object,
             (content_constant)
             (percent_curation_rewards)
             (percent_content_rewards)
+            (author_reward_curve)
+            (curation_reward_curve)
          )
 CHAINBASE_SET_INDEX_TYPE( steemit::chain::reward_fund_object, steemit::chain::reward_fund_index )

libraries/chain/include/steemit/chain/util/reward.hpp

@@ -27,22 +27,20 @@ struct comment_reward_context
    uint128_t  total_reward_shares2;
    asset      total_reward_fund_steem;
    price      current_steem_price;
+   curve_id   reward_curve = quadratic;
+   uint128_t  content_constant = STEEMIT_CONTENT_CONSTANT_HF0;
 };
 
 uint64_t get_rshare_reward( const comment_reward_context& ctx );
 
-uint64_t get_rshare_reward( const comment_reward_context& ctx, const reward_fund_object& rf );
-
-uint64_t get_vote_weight( uint64_t vote_rshares, const reward_fund_object& rf );
+uint64_t get_vote_weight( uint64_t vote_rshares, const curve_id& curve, const uint128_t& content_constant );
 
 inline uint128_t get_content_constant_s()
 {
    return STEEMIT_CONTENT_CONSTANT_HF0; // looking good for posters
 }
 
-uint128_t calculate_claims( const uint128_t& rshares );
-
-uint128_t calculate_claims( const uint128_t& rshares, const reward_fund_object& rf );
+uint128_t calculate_claims( const uint128_t& rshares, const curve_id& curve = quadratic, const uint128_t& content_constant = STEEMIT_CONTENT_CONSTANT_HF0 );
 
 inline bool is_comment_payout_dust( const price& p, uint64_t steem_payout )
 {
@@ -58,4 +56,6 @@ FC_REFLECT( steemit::chain::util::comment_reward_context,
    (total_reward_shares2)
    (total_reward_fund_steem)
    (current_steem_price)
+   (reward_curve)
+   (content_constant)
    )

libraries/chain/steem_evaluator.cpp

@@ -1345,8 +1345,8 @@ void vote_evaluator::do_apply( const vote_operation& o )
                if( _db.has_hardfork( STEEMIT_HARDFORK_0_17__774 ) )
                {
                   const auto& reward_fund = _db.get_reward_fund( comment );
-                  uint64_t old_weight = util::get_vote_weight( old_vote_rshares.value, reward_fund );
-                  uint64_t new_weight = util::get_vote_weight( comment.vote_rshares.value, reward_fund );
+                  uint64_t old_weight = util::get_vote_weight( old_vote_rshares.value, reward_fund.curation_reward_curve, reward_fund.content_constant );
+                  uint64_t new_weight = util::get_vote_weight( comment.vote_rshares.value, reward_fund.curation_reward_curve, reward_fund.content_constant );
                   cv.weight = new_weight - old_weight;
                }
                else if ( _db.has_hardfork( STEEMIT_HARDFORK_0_1 ) )

libraries/chain/util/reward.cpp

@@ -11,43 +11,12 @@ uint64_t get_rshare_reward( const comment_reward_context& ctx )
    FC_ASSERT( ctx.rshares > 0 );
    FC_ASSERT( ctx.total_reward_shares2 > 0 );
 
-   u256 rs(ctx.rshares.value);
-   u256 rf(ctx.total_reward_fund_steem.amount.value);
-   u256 total_rshares2 = to256( ctx.total_reward_shares2 );
-
-   //idump( (ctx) );
-
-   u256 rs2 = to256( calculate_claims( ctx.rshares.value ) );
-   rs2 = ( rs2 * ctx.reward_weight ) / STEEMIT_100_PERCENT;
-
-   u256 payout_u256 = ( rf * rs2 ) / total_rshares2;
-   FC_ASSERT( payout_u256 <= u256( uint64_t( std::numeric_limits<int64_t>::max() ) ) );
-   uint64_t payout = static_cast< uint64_t >( payout_u256 );
-
-   if( is_comment_payout_dust( ctx.current_steem_price, payout ) )
-      payout = 0;
-
-   asset max_steem = to_steem( ctx.current_steem_price, ctx.max_sbd );
-
-   payout = std::min( payout, uint64_t( max_steem.amount.value ) );
-
-   return payout;
-   } FC_CAPTURE_AND_RETHROW( (ctx) )
-}
-
-uint64_t get_rshare_reward( const comment_reward_context& ctx, const reward_fund_object& rf_object )
-{
-   try
-   {
-   FC_ASSERT( ctx.rshares > 0 );
-   FC_ASSERT( ctx.total_reward_shares2 > 0 );
-
    u256 rf(ctx.total_reward_fund_steem.amount.value);
    u256 total_claims = to256( ctx.total_reward_shares2 );
 
    //idump( (ctx) );
 
-   u256 claim = to256( calculate_claims( ctx.rshares.value, rf_object ) );
+   u256 claim = to256( calculate_claims( ctx.rshares.value, ctx.reward_curve, ctx.content_constant ) );
    claim = ( claim * ctx.reward_weight ) / STEEMIT_100_PERCENT;
 
    u256 payout_u256 = ( rf * claim ) / total_claims;
@@ -81,28 +50,51 @@ uint64_t get_vote_weight( uint64_t vote_rshares, const reward_fund_object& rf )
    return result;
 }
 
+uint64_t get_vote_weight( uint64_t vote_rshares, const curve_id& curve, const uint128_t& content_constant )
+{
+   uint64_t result = 0;
+
+   switch( curve )
+   {
+      case quadratic_curation:
+         {
+            uint128_t two_alpha = content_constant * 2;
+            result = ( uint128_t( vote_rshares, 0 ) / ( two_alpha + vote_rshares ) ).to_uint64();
+         }
+         break;
+      case square_root:
+         //result = rshares;
+         break;
+   }
+
+   return result;
+}
+
 uint128_t calculate_claims( const uint128_t& rshares )
 {
    uint128_t s = get_content_constant_s();
    uint128_t rshares_plus_s = rshares + s;
    return rshares_plus_s * rshares_plus_s - s * s;
 }
 
-uint128_t calculate_claims( const uint128_t& rshares, const reward_fund_object& rf )
+uint128_t calculate_claims( const uint128_t& rshares, const curve_id& curve, const uint128_t& content_constant )
 {
    uint128_t result = 0;
-   if( rf.name == STEEMIT_POST_REWARD_FUND_NAME || rf.name == STEEMIT_COMMENT_REWARD_FUND_NAME )
-   {
-      uint128_t s = rf.content_constant;
-      uint128_t rshares_plus_s = rshares + s;
-      result = rshares_plus_s * rshares_plus_s - s * s;
-   }
-   else
+
+   switch( curve )
    {
-      wlog( "Unknown reward fund type ${rf}", ("rf",rf.name) );
+      case quadratic:
+         {
+            uint128_t rshares_plus_s = rshares + content_constant;
+            result = rshares_plus_s * rshares_plus_s - content_constant * content_constant;
+         }
+         break;
+      case linear:
+         result = rshares;
+         break;
    }
 
    return result;
 }
 
-} } }
+} } } // steemit::chain::util

tests/tests/operation_time_tests.cpp

@@ -318,7 +318,9 @@ BOOST_AUTO_TEST_CASE( recent_claims_decay )
       tx.sign( alice_private_key, db.get_chain_id() );
       db.push_transaction( tx, 0 );
 
-      auto alice_vshares = util::calculate_claims( db.get_comment( "alice", string( "test" ) ).net_rshares.value, db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ) );
+      auto alice_vshares = util::calculate_claims( db.get_comment( "alice", string( "test" ) ).net_rshares.value,
+         db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ).author_reward_curve,
+         db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ).content_constant );
 
       generate_blocks( 5 );
 
@@ -341,7 +343,9 @@ BOOST_AUTO_TEST_CASE( recent_claims_decay )
       }
 
       auto bob_cashout_time = db.get_comment( "bob", string( "test" ) ).cashout_time;
-      auto bob_vshares = util::calculate_claims( db.get_comment( "bob", string( "test" ) ).net_rshares.value, db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ) );
+      auto bob_vshares = util::calculate_claims( db.get_comment( "bob", string( "test" ) ).net_rshares.value,
+         db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ).author_reward_curve,
+         db.get< reward_fund_object, by_name >( STEEMIT_POST_REWARD_FUND_NAME ).content_constant );
 
       generate_block();