From 7fe374b3afed0d25771d75df066bae14d9d91d6a Mon Sep 17 00:00:00 2001
From: GeorgeM <georgemansbridge@msn.com>
Date: Tue, 11 Jul 2023 19:23:48 +0100
Subject: [PATCH 1/4] make hashing algorithm faster by doing a direct bit ->
 int conversion in c with numpy

---
 cubes.py | 39 +++++++++++++--------------------------
 1 file changed, 13 insertions(+), 26 deletions(-)

diff --git a/cubes.py b/cubes.py
index 18e6fb5..3e8a856 100644
--- a/cubes.py
+++ b/cubes.py
@@ -151,40 +151,27 @@ def generate_polycubes(n, use_cache=False):
 
 def rle(polycube):
     """
-    Computes a simple run-length encoding of a given polycube. This function allows cubes to be more quickly compared via hashing.
+    Computes a simple hash of a given polycube.
+    It does this by converting the polycube into a 1d array and then interpreting those bits as a unsigned integer
+    This function allows cubes to be more quickly compared via hashing.
   
-    Converts a {0,1} nd array into a tuple that encodes the same shape. The array is first flattened, and then the following algorithm is applied:
-
-    1) The first three values in tuple contain the x,y,z dimension sizes of the array
-    2) Each string of zeros of length n is replaced with a single value -n
-    3) Each string of ones of length m is replaced with a single value +m
+    Converts a {0,1} nd array into a single unique large integer
   
     Parameters:
     polycube (np.array): 3D Numpy byte array where 1 values indicate polycube positions
   
     Returns:
-    tuple(int): Run length encoded polycube in the form (X, Y, Z, a, b, c, ...)
+    int: a unique integer hash
 
     """
-    r = []
-    r.extend(polycube.shape)
-    current = None
-    val = 0
-    for x in polycube.flat:
-        if current is None:
-            current = x
-            val = 1
-            pass
-        elif current == x:
-            val += 1
-        elif current != x:
-            r.append(val if current == 1 else -val)
-            current = x
-            val = 1
-
-    r.append(val if current == 1 else -val)
-
-    return tuple(r)
+
+    pack_cube = np.packbits(polycube.flatten())
+    out = 0
+    for part in pack_cube:
+        out = out * 256
+        out += int(part)
+    return out
+
 
 def cube_exists_rle(polycube, polycubes_rle):
     """

From 1c2f044cc4c3fa69ab2bff6baa01cd16ca6875dc Mon Sep 17 00:00:00 2001
From: GeorgeM <georgemansbridge@msn.com>
Date: Tue, 11 Jul 2023 19:51:01 +0100
Subject: [PATCH 2/4] fix bug where dimensiuons of space wherent included in
 hash causing misscount

---
 cubes.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/cubes.py b/cubes.py
index 3e8a856..6b38f85 100644
--- a/cubes.py
+++ b/cubes.py
@@ -149,7 +149,7 @@ def generate_polycubes(n, use_cache=False):
 
     return polycubes
 
-def rle(polycube):
+def rle(polycube: np.ndarray):
     """
     Computes a simple hash of a given polycube.
     It does this by converting the polycube into a 1d array and then interpreting those bits as a unsigned integer
@@ -166,10 +166,10 @@ def rle(polycube):
     """
 
     pack_cube = np.packbits(polycube.flatten())
-    out = 0
+    data = 0
     for part in pack_cube:
-        out = out * 256
-        out += int(part)
+        data = (data << 8) + int(part)
+    out = (data * 100000) + (polycube.shape[0] * 1000) + (polycube.shape[1] * 10) + (polycube.shape[2]) # add volume dimensions to lower bits of hash
     return out
 
 

From dd05504268521f84cde92a1f7ea016d80722b61a Mon Sep 17 00:00:00 2001
From: GeorgeM <georgemansbridge@msn.com>
Date: Tue, 11 Jul 2023 19:53:46 +0100
Subject: [PATCH 3/4] remove type hinting to conform with rest of codebase

---
 cubes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cubes.py b/cubes.py
index 6b38f85..7cb1a63 100644
--- a/cubes.py
+++ b/cubes.py
@@ -149,7 +149,7 @@ def generate_polycubes(n, use_cache=False):
 
     return polycubes
 
-def rle(polycube: np.ndarray):
+def rle(polycube):
     """
     Computes a simple hash of a given polycube.
     It does this by converting the polycube into a 1d array and then interpreting those bits as a unsigned integer

From 42fbab972e96dec49db4c58c5870c42200e7e9bb Mon Sep 17 00:00:00 2001
From: GeorgeM <georgemansbridge@msn.com>
Date: Wed, 12 Jul 2023 02:05:42 +0100
Subject: [PATCH 4/4] fix for possible hash collisions in n>10

---
 cubes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cubes.py b/cubes.py
index 7cb1a63..530816b 100644
--- a/cubes.py
+++ b/cubes.py
@@ -169,7 +169,7 @@ def rle(polycube):
     data = 0
     for part in pack_cube:
         data = (data << 8) + int(part)
-    out = (data * 100000) + (polycube.shape[0] * 1000) + (polycube.shape[1] * 10) + (polycube.shape[2]) # add volume dimensions to lower bits of hash
+    out = (data * 100000000) + (polycube.shape[0] * 100000) + (polycube.shape[1] * 100) + (polycube.shape[2]) # add volume dimensions to lower bits of hash
     return out