### 5.25.19 Triangular window function : triangle_window

triangle_window takes as arguments a real vector v of length n and optionally an integer d∈{−1,0,1} (by default d=0 ) and/or an interval n_{1} .. n_{2} (with default values n_{1}=0 and n_{2}=n−1 ), and returns the elementwise product of the vector [v_{n1},…,v_{n2}] and the vector w of length N=n_{2}−n_{1}+1 defined by

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for k=0,1,…,N−1 (the case d=−1 is called the Bartlett window function). For example, input :

L:=triangle_window(randvector(1000,0..1),1):;

followed by scatterplot(L).