SP1 Exercise 3 Index   <<   >>


 

Generate a random 30 by 40 boolean matrix with density 0.2.

   b ← 1=?30 40⍴5

Where do clusters occur? One way to find them is to mark the
3 by 3 neighborhoods having at least five 1s.

If f is the function that does this marking, you can “eyeball” the result by:

   ' ○*⍟'[1+ b+2×f b]





















f  ← 5 ≤ {+/,⍵}⌺3 3     ⍝ 3-train

f1 ← {5≤{+/,⍵}⌺3 3 ⊢⍵}  ⍝ dfn