smarnach · April 2, 2012 12:16 · Apr 2, 2012
diff --git a/gistfile1.py b/gistfile1.py
@@ -0,0 +1,36 @@
+import timeit
+import numpy
+import scipy.ndimage.morphology
+
+def f0(a, kernel):
+    b = numpy.convolve(a, kernel, mode="same") > 1
+    b[1:] |= b[:-1]
+    b[:-1] |= b[1:]
+    return b
+
+def f1(a, kernel):
+    b = numpy.convolve(a, kernel, mode="same") > 1
+    return b | numpy.r_[0, b[:-1]] | numpy.r_[b[1:], 0]
+
+def f2(a, kernel):
+    b = numpy.convolve(a, kernel, mode="same") > 1
+    return numpy.convolve(b, kernel, mode="same") > 0
+
+def f3(a, kernel):
+    b = numpy.convolve(a, kernel, mode="same") > 1
+    return scipy.ndimage.morphology.binary_dilation(b)
+
+def f4(a, kernel):
+    b = numpy.zeros(a.shape)
+    for x in range(len(a)-2):
+        if a[x:x+3].sum()>1:
+            b[x:x+3]=1
+    return b
+
+a = numpy.random.randint(2, size=1000000)
+kernel = numpy.array([1, 1, 1])
+for i in range(5):
+    fname = "f" + str(i)
+    print timeit.timeit(fname + "(a, kernel)",
+                        "from __main__ import a, kernel, " + fname,
+                        number=10)