Initial commit

2024/16/numpy_test.py

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+#!/usr/bin/env python3
+
+import sys
+
+import numpy as np
+import scipy as sp
+
+dtype = np.int32
+
+input_file = sys.argv[1]
+
+with open(input_file) as fd:
+    lines = [line.rstrip() for line in fd.readlines()]
+
+height = len(lines)
+width = len(lines[0])
+start = height - 2, 1
+stop = 1, width - 2
+
+directions = [
+    (-1, 0),  # ^ North
+    (0, 1),  # > East
+    (1, 0),  # v South
+    (0, -1),  # < West
+]
+directions_keys = ("^", ">", "v", "<")
+
+walls = np.zeros((height, width), dtype)
+for i in range(height):
+    for j in range(width):
+        if lines[i][j] == "#":
+            walls[i, j] = 1
+invwalls = 1 - walls
+
+# print("Walls")
+# print(walls)
+
+# TEST 4
+
+scores = np.zeros((height, width, len(directions)), dtype)
+scores[start[0], start[1], 1] = 1
+
+for i in range(1000):
+    print("Step", i)
+    oldscores = scores.copy()
+    for od, odir in enumerate(directions):
+        for nd, ndir in enumerate(directions):
+            score = scores[:, :, nd]
+            moved = sp.ndimage.shift(oldscores[:, :, od], ndir)
+            increment = 1 if nd == od else 1001
+            moved = (moved + increment) * (moved > 0)
+            moved = moved * invwalls
+            mask = (moved > 0) & ((score == 0) | (score > moved))
+            scores[:, :, nd] = (score * ~mask) + (moved * mask)
+
+    # for d, dir in enumerate(directions):
+    #     print("Direction", directions_keys[d])
+    #     print(scores[:, :, d])
+
+    if (scores == oldscores).all():
+        break
+else:
+    print("Limit!")
+
+end_score = min(filter(lambda d: d > 0, scores[stop])) - 1
+print(f"{end_score=}")
+
+# TEST 3
+
+# scores = [np.zeros((height, width), dtype) for _ in directions]
+# scores[1][start] = 1
+#
+# for i in range(100):
+#     print("Step", i)
+#     for od, odir in enumerate(directions):
+#         oldscore = scores[od].copy()
+#         for nd, ndir in enumerate(directions):
+#             score = scores[nd]
+#             moved = sp.ndimage.shift(oldscore, ndir)
+#             increment = 1 if nd == od else 1001
+#             moved = (moved + increment) * (moved > 0)
+#             moved = moved * invwalls
+#             mask = (moved > 0) & ((score == 0) | (score > moved))
+#             scores[nd] = (score * ~mask) + (moved * mask)
+#
+#     final_score = None
+#     for d, dir in enumerate(directions):
+#         print("Direction", directions_keys[d])
+#         print(scores[d])
+#         end_score = scores[d][stop]
+#         if end_score > 0:
+#             if final_score is None or end_score < final_score:
+#                 final_score = end_score
+#
+#     if final_score:
+#         final_score -= 1
+#         print(f"{final_score=}")
+#         break
+# else:
+#     print("Limit!")
+
+
+# TEST 2
+
+# score = np.zeros((height, width), dtype)
+# score[start] = 1
+#
+# for i in range(10):
+#     print("Step", i)
+#     oldscore = score.copy()
+#     for nd, ndir in enumerate(directions):
+#         moved = sp.ndimage.shift(oldscore, ndir)
+#         moved = (moved + 1) * (moved > 0)
+#         moved = moved * invwalls
+#         mask = (moved > 0) & ((score == 0) | (score > moved))
+#         score = (score * ~mask) + (moved * mask)
+#     print(score)
+
+# TEST 1
+
+# directions = np.array([[0, 1, 0], [1, 1, 1], [0, 1, 0]], dtype)
+#
+# visited = np.zeros((height, width), dtype)
+# visited[start] = 1
+#
+# for i in range(1000):
+#     print("Step", i)
+#     new = sp.signal.convolve2d(visited, directions, mode="same")
+#     visited = (((new > 0) - walls) > 0)
+#     print(visited * 1)
+#     if visited[stop]:
+#         break
+# else:
+#     print("Limit!")
+# print(i)