Hash updates (#151)

* Remove power of 2 recommendation.

* Raise runtime error in case hash is somehow set before threads.

* formatting

Author: johndoknjas

README.md

@@ -46,7 +46,7 @@ There are some default engine settings used by this wrapper. For increasing Stoc
     "Min Split Depth": 0,
     "Threads": 1, # More threads will make the engine stronger, but should be kept at less than the number of logical processors on your computer.
     "Ponder": False,
-    "Hash": 16, # Default size is 16 MB. It's recommended that you increase this value, but keep it as some power of 2. E.g., if you're fine using 2 GB of RAM, set Hash to 2048 (11th power of 2).
+    "Hash": 16, # Default size is 16 MB. It's recommended that you increase this value, to however many MBs of RAM you're willing to allocate (e.g., 2048 for 2GB of RAM).
     "MultiPV": 1,
     "Skill Level": 20,
     "Move Overhead": 10,

stockfish/models.py

@@ -307,7 +307,7 @@ def update_engine_parameters(
             elif "UCI_Elo" in new_param_values:
                 new_param_values.update({"UCI_LimitStrength": True})
 
-        if "Threads" in new_param_values:
+        if going_to_set_threads := ("Threads" in new_param_values):
             # Recommended to set the hash param after threads.
             threads_value = new_param_values["Threads"]
             del new_param_values["Threads"]
@@ -321,6 +321,12 @@ def update_engine_parameters(
             new_param_values["Hash"] = hash_value
 
         for name, value in new_param_values.items():
+            if name == "Hash" and going_to_set_threads:
+                raise RuntimeError(
+                    "Unexpected error - should be setting hash after threads"
+                )
+            if name == "Threads":
+                going_to_set_threads = False
             self._set_option(name, value)
         self.set_fen_position(self.get_fen_position())
         # Getting SF to set the position again, since UCI option(s) have been updated.