feat: use hsitoric price precision for improved accuracy

closes freqtrade#11203

freqtrade/optimize/backtesting.py

@@ -9,14 +9,18 @@
 from copy import deepcopy
 from datetime import datetime, timedelta
 
-from numpy import nan
-from pandas import DataFrame
+from numpy import isnan, nan
+from pandas import DataFrame, Series
 
 from freqtrade import constants
 from freqtrade.configuration import TimeRange, validate_config_consistency
 from freqtrade.constants import DATETIME_PRINT_FORMAT, Config, IntOrInf, LongShort
 from freqtrade.data import history
-from freqtrade.data.btanalysis import find_existing_backtest_stats, trade_list_to_dataframe
+from freqtrade.data.btanalysis import (
+    find_existing_backtest_stats,
+    get_significant_digits_over_time,
+    trade_list_to_dataframe,
+)
 from freqtrade.data.converter import trim_dataframe, trim_dataframes
 from freqtrade.data.dataprovider import DataProvider
 from freqtrade.data.metrics import combined_dataframes_with_rel_mean
@@ -35,7 +39,7 @@
     price_to_precision,
     timeframe_to_seconds,
 )
-from freqtrade.exchange.exchange import Exchange
+from freqtrade.exchange.exchange import TICK_SIZE, Exchange
 from freqtrade.ft_types import (
     BacktestContentType,
     BacktestContentTypeIcomplete,
@@ -121,6 +125,7 @@ def __init__(self, config: Config, exchange: Exchange | None = None) -> None:
         self.order_id_counter: int = 0
 
         config["dry_run"] = True
+        self.price_pair_prec: dict[str, Series] = {}
         self.run_ids: dict[str, str] = {}
         self.strategylist: list[IStrategy] = []
         self.all_bt_content: dict[str, BacktestContentType] = {}
@@ -189,7 +194,6 @@ def __init__(self, config: Config, exchange: Exchange | None = None) -> None:
             self.fee = max(fee for fee in fees if fee is not None)
             logger.info(f"Using fee {self.fee:.4%} - worst case fee from exchange (lowest tier).")
         self.precision_mode = self.exchange.precisionMode
-        self.precision_mode_price = self.exchange.precision_mode_price
 
         if self.config.get("freqai_backtest_live_models", False):
             from freqtrade.freqai.utils import get_timerange_backtest_live_models
@@ -316,6 +320,9 @@ def load_bt_data(self) -> tuple[dict[str, DataFrame], TimeRange]:
 
         self.progress.set_new_value(1)
         self._load_bt_data_detail()
+        self.price_pair_prec = {}
+        for pair in self.pairlists.whitelist:
+            self.price_pair_prec[pair] = get_significant_digits_over_time(data[pair])
         return data, self.timerange
 
     def _load_bt_data_detail(self) -> None:
@@ -385,6 +392,22 @@ def _load_bt_data_detail(self) -> None:
         else:
             self.futures_data = {}
 
+    def get_pair_precision(self, pair: str, current_time: datetime) -> tuple[float, int]:
+        """
+        Get pair precision at that moment in time
+        :param pair: Pair to get precision for
+        :param current_time: Time to get precision for
+        :return: tuple of price precision, precision_mode_price for the pair at that given time.
+        """
+        precision_series = self.price_pair_prec.get(pair)
+        if precision_series is not None:
+            precision = precision_series.asof(current_time)
+
+        if not isnan(precision):
+            # Force tick size if we define the precision
+            return precision, TICK_SIZE
+        return self.exchange.get_precision_price(pair), self.exchange.precision_mode_price
+
     def disable_database_use(self):
         disable_database_use(self.timeframe)
 
@@ -793,7 +816,7 @@ def _get_exit_for_signal(
                     )
                     if rate is not None and rate != close_rate:
                         close_rate = price_to_precision(
-                            rate, trade.price_precision, self.precision_mode_price
+                            rate, trade.price_precision, trade.precision_mode_price
                         )
                     # We can't place orders lower than current low.
                     # freqtrade does not support this in live, and the order would fill immediately
@@ -926,6 +949,7 @@ def get_valid_price_and_stake(
         trade: LocalTrade | None,
         order_type: str,
         price_precision: float | None,
+        precision_mode_price: int,
     ) -> tuple[float, float, float, float]:
         if order_type == "limit":
             new_rate = strategy_safe_wrapper(
@@ -941,9 +965,7 @@ def get_valid_price_and_stake(
             # We can't place orders higher than current high (otherwise it'd be a stop limit entry)
             # which freqtrade does not support in live.
             if new_rate is not None and new_rate != propose_rate:
-                propose_rate = price_to_precision(
-                    new_rate, price_precision, self.precision_mode_price
-                )
+                propose_rate = price_to_precision(new_rate, price_precision, precision_mode_price)
             if direction == "short":
                 propose_rate = max(propose_rate, row[LOW_IDX])
             else:
@@ -1036,7 +1058,7 @@ def _enter_trade(
         pos_adjust = trade is not None and requested_rate is None
 
         stake_amount_ = stake_amount or (trade.stake_amount if trade else 0.0)
-        precision_price = self.exchange.get_precision_price(pair)
+        precision_price, precision_mode_price = self.get_pair_precision(pair, current_time)
 
         propose_rate, stake_amount, leverage, min_stake_amount = self.get_valid_price_and_stake(
             pair,
@@ -1049,6 +1071,7 @@ def _enter_trade(
             trade,
             order_type,
             precision_price,
+            precision_mode_price,
         )
 
         # replace proposed rate if another rate was requested
@@ -1124,7 +1147,7 @@ def _enter_trade(
                     amount_precision=precision_amount,
                     price_precision=precision_price,
                     precision_mode=self.precision_mode,
-                    precision_mode_price=self.precision_mode_price,
+                    precision_mode_price=precision_mode_price,
                     contract_size=contract_size,
                     orders=[],
                 )