1 files changed, 48 insertions, 0 deletions
diff --git a/interval_utils.py b/interval_utils.py
new file mode 100644
index 0000000..4c3f8e2
--- /dev/null
+++ b/interval_utils.py
@@ -0,0 +1,48 @@
+from functools import reduce
+from math import pi
+import math
+
+def merge_intervals(intervals):
+    sorted_by_lower_bound = sorted(intervals, key=lambda tup: tup[0])
+    merged = []
+
+    for higher in sorted_by_lower_bound:
+        if not merged:
+            merged.append(higher)
+        else:
+            lower = merged[-1]
+            # test for intersection between lower and higher:
+            # we know via sorting that lower[0] <= higher[0]
+            if higher[0] <= lower[1]:
+                upper_bound = max(lower[1], higher[1])
+                merged[-1] = (lower[0], upper_bound)  # replace by merged interval
+            else:
+                merged.append(higher)
+    
+    return merged
+
+def clean_intervals(intervals):
+    return list(filter(lambda i : i[0]!=i[1],intervals))
+
+def canonicalize_angle_interval(i):
+    a=i[0] % (2*pi)
+    b=i[1] % (2*pi)
+
+    if a <= b:
+        return [(a,b)]
+    else:
+        return [(0,b),(a,2*pi)]
+
+def invert_angle_intervals(intervals):
+    flattened = reduce(lambda a,b:a+b, (map(lambda a: [a[0],a[1]], intervals)))
+    return clean_intervals(list(zip([0]+flattened, flattened+[2*pi]))[::2])
+
+def find_largest_angle_interval(intervals):
+    if (intervals[0][0]==0 and intervals[-1][1]==2*pi):
+        # these two intervals actually are one.
+        intervals_ = intervals[1:-1] + [(intervals[-1][0], intervals[0][1]+2*pi)]
+    else:
+        intervals_ = intervals
+
+    return max(intervals_, key=lambda p:p[1]-p[0])
+