Add convolve() to the itertools recipes (GH-23928)
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 612a66f..03416a0 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -786,6 +786,18 @@
def dotproduct(vec1, vec2):
return sum(map(operator.mul, vec1, vec2))
+ def convolve(signal, kernel):
+ # See: https://betterexplained.com/articles/intuitive-convolution/
+ # convolve(data, [0.25, 0.25, 0.25, 0.25]) --> Moving average (blur)
+ # convolve(data, [1, -1]) --> 1st finite difference (1st derivative)
+ # convolve(data, [1, -2, 1]) --> 2nd finite difference (2nd derivative)
+ kernel = list(reversed(kernel))
+ n = len(kernel)
+ window = collections.deque([0] * n, maxlen=n)
+ for x in chain(signal, repeat(0, n-1)):
+ window.append(x)
+ yield sum(map(operator.mul, kernel, window))
+
def flatten(list_of_lists):
"Flatten one level of nesting"
return chain.from_iterable(list_of_lists)