Merge pull request #252 from wowario/testnet

refactor difficulty for testnet

src/cryptonote_basic/difficulty.cpp

@@ -364,10 +364,44 @@ namespace cryptonote {
   // LWMA-1 difficulty algorithm 
   // Copyright (c) 2017-2019 Zawy, MIT License
   // https://github.com/zawy12/difficulty-algorithms/issues/3
-  difficulty_type next_difficulty_v5(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT, uint64_t FORK_HEIGHT, uint64_t difficulty_guess) {
+  difficulty_type next_difficulty_v5(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT) {
     assert(timestamps.size() == cumulative_difficulties.size() && timestamps.size() <= N+1 );
 
-    if (HEIGHT >= FORK_HEIGHT && HEIGHT < FORK_HEIGHT + N) { return difficulty_guess; }
+    if (HEIGHT >= 81769 && HEIGHT < 81769 + N) { return 10000000; }
+    assert(timestamps.size() == N+1);
+
+    uint64_t  L(0), next_D, i, this_timestamp(0), previous_timestamp(0), avg_D;
+
+    previous_timestamp = timestamps[0]-T;
+    for ( i = 1; i <= N; i++) {
+    // Safely prevent out-of-sequence timestamps
+      if ( timestamps[i]  > previous_timestamp ) {   this_timestamp = timestamps[i];  }
+      else {  this_timestamp = previous_timestamp+1;   }
+      L +=  i*std::min(6*T ,this_timestamp - previous_timestamp);
+      previous_timestamp = this_timestamp;
+    }
+    if (L < N*N*T/20 ) { L =  N*N*T/20; }
+    avg_D = static_cast<uint64_t>(( cumulative_difficulties[N] - cumulative_difficulties[0] )/ N);
+
+    // Prevent round off error for small D and overflow for large D.
+    if (avg_D > 2000000*N*N*T) {
+      next_D = (avg_D/(200*L))*(N*(N+1)*T*99);
+    }
+    else {    next_D = (avg_D*N*(N+1)*T*99)/(200*L);    }
+
+    // Make all insignificant digits zero for easy reading.
+    i = 1000000000;
+    while (i > 1) {
+      if ( next_D > i*100 ) { next_D = ((next_D+i/2)/i)*i; break; }
+      else { i /= 10; }
+    }
+    return  next_D;
+  }
+
+  difficulty_type next_difficulty_test(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT) {
+    assert(timestamps.size() == cumulative_difficulties.size() && timestamps.size() <= N+1 );
+
+    if (HEIGHT < N) { return 1337; }
     assert(timestamps.size() == N+1);
 
     uint64_t  L(0), next_D, i, this_timestamp(0), previous_timestamp(0), avg_D;

src/cryptonote_basic/difficulty.h

@@ -61,7 +61,8 @@ namespace cryptonote
     difficulty_type next_difficulty_v2(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t target_seconds);
     difficulty_type next_difficulty_v3(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties);
     difficulty_type next_difficulty_v4(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t height);
-    difficulty_type next_difficulty_v5(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT, uint64_t FORK_HEIGHT, uint64_t difficulty_guess);
+    difficulty_type next_difficulty_v5(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT);
+    difficulty_type next_difficulty_test(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, uint64_t T, uint64_t N, uint64_t HEIGHT);
 
     std::string hex(difficulty_type v);
 }

src/cryptonote_config.h

@@ -89,8 +89,6 @@
 #define DIFFICULTY_BLOCKS_COUNT_V3                      DIFFICULTY_WINDOW_V3 + 1 // added +1 to make N=N
 #define DIFFICULTY_BLOCKS_COUNT_V2                      DIFFICULTY_WINDOW_V2 + 1 // added +1 to make N=N
 #define DIFFICULTY_BLOCKS_COUNT                         DIFFICULTY_WINDOW + DIFFICULTY_LAG
-#define DIFFICULTY_FORK_HEIGHT                          81769 // ~14 February 2019
-#define DIFFICULTY_RESET                                10000000 // 10 million
 
 #define CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1   DIFFICULTY_TARGET_V1 * CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_BLOCKS
 #define CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2   DIFFICULTY_TARGET_V2 * CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_BLOCKS

src/cryptonote_core/blockchain.cpp

@@ -887,21 +887,25 @@ difficulty_type Blockchain::get_difficulty_for_next_block()
   uint64_t T = DIFFICULTY_TARGET_V2;
   uint64_t N = DIFFICULTY_WINDOW_V3;
   uint64_t HEIGHT = m_db->height();
-  uint64_t FORK_HEIGHT = DIFFICULTY_FORK_HEIGHT;
-  uint64_t difficulty_guess = DIFFICULTY_RESET;
 
   difficulty_type diff = next_difficulty(timestamps, difficulties, target);
 
-  if (version >= 11) {
+  if (m_nettype == MAINNET) {
-    diff = next_difficulty_v5(timestamps, difficulties, T, N, HEIGHT, FORK_HEIGHT, difficulty_guess);
+    if (version >= 11) {
-  } else if (version == 10) {
+      diff = next_difficulty_v5(timestamps, difficulties, T, N, HEIGHT);
-    diff = next_difficulty_v4(timestamps, difficulties, height);
+    } else if (version == 10) {
-  } else if (version == 9) {
+      diff = next_difficulty_v4(timestamps, difficulties, height);
-    diff = next_difficulty_v3(timestamps, difficulties);
+    } else if (version == 9) {
-  } else if (version == 8) {
+      diff = next_difficulty_v3(timestamps, difficulties);
-    diff = next_difficulty_v2(timestamps, difficulties, target);
+    } else if (version == 8) {
-  } else {
+      diff = next_difficulty_v2(timestamps, difficulties, target);
-    diff = next_difficulty(timestamps, difficulties, target);
+    } else {
+      diff = next_difficulty(timestamps, difficulties, target);
+    }
+  }
+
+  if (m_nettype == TESTNET) {
+    diff = next_difficulty_test(timestamps, difficulties, T, N, HEIGHT);
   }
 
   CRITICAL_REGION_LOCAL1(m_difficulty_lock);
@@ -1147,20 +1151,24 @@ difficulty_type Blockchain::get_next_difficulty_for_alternative_chain(const std:
   uint64_t T = DIFFICULTY_TARGET_V2;
   uint64_t N = DIFFICULTY_WINDOW_V3;
   uint64_t HEIGHT = m_db->height();
-  uint64_t FORK_HEIGHT = DIFFICULTY_FORK_HEIGHT;
-  uint64_t difficulty_guess = DIFFICULTY_RESET;
 
   // calculate the difficulty target for the block and return it
-  if (version >= 11) {
+  if (m_nettype == MAINNET) {
-    return next_difficulty_v5(timestamps, cumulative_difficulties, T, N, HEIGHT, FORK_HEIGHT, difficulty_guess);
+    if (version >= 11) {
-  } else if (version == 10) {
+      return next_difficulty_v5(timestamps, cumulative_difficulties, T, N, HEIGHT);
-    return next_difficulty_v4(timestamps, cumulative_difficulties, height);
+    } else if (version == 10) {
-  } else if (version == 9) {
+      return next_difficulty_v4(timestamps, cumulative_difficulties, height);
-    return next_difficulty_v3(timestamps, cumulative_difficulties);
+    } else if (version == 9) {
-  } else if (version == 8) {
+      return next_difficulty_v3(timestamps, cumulative_difficulties);
-    return next_difficulty_v2(timestamps, cumulative_difficulties, target);
+    } else if (version == 8) {
-  } else {
+      return next_difficulty_v2(timestamps, cumulative_difficulties, target);
-    return next_difficulty(timestamps, cumulative_difficulties, target);
+    } else {
+      return next_difficulty(timestamps, cumulative_difficulties, target);
+    }
+  }
+
+  if (m_nettype == TESTNET) {
+    return next_difficulty_test(timestamps, cumulative_difficulties, T, N, HEIGHT);
   }
 }
 //------------------------------------------------------------------