Sum function

(require '[kigubkur.datafun [sum :refer [sum]]])

Examples

Sum of a vector

This returns the sum of elements.

=> (def r [[1 2 3 4]])
=> (def c [[1][2][3][4]])
=> (view r)
[1 2 3 4]
Order -> 1 x 4
=> (sum r)
10
=> (view c)
[1]
[2]
[3]
[4]
Order -> 4 x 1
=> (sum c)
10

Sum of a matrix

By default this returns a row vector containing the sum of each column.

=> (def M [[1 2 3 4 5] [1 2 3 4 5] [1 2 3 4 5] [1 2 3 4 5]])
=> (view M)
[1 2 3 4 5]
[1 2 3 4 5]
[1 2 3 4 5]
[1 2 3 4 5]
Order -> 4 x 5
=> (view (sum M))
[4 8 12 16 20]
Order -> 1 x 5

But for sum of each row

=> (sum M "rows")
[[15 15 15 15]]

Sum of a block

(require '[kigubkur.construct [blocking :refer [block]]])

=> (def L [[1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]
           [1 2 3 4 5 6 7 8 9 10]])
=> (def B (block L 5))
=> (pprint B)
[[{:A11 [[1 2 3 4 5]
         [1 2 3 4 5]
         [1 2 3 4 5]
         [1 2 3 4 5]
         [1 2 3 4 5]],
   :A12 [[6 7 8 9 10]
         [6 7 8 9 10]
         [6 7 8 9 10]
         [6 7 8 9 10]
         [6 7 8 9 10]]}]
 [{:A22 [[6 7 8 9 10]
         [6 7 8 9 10]],
   :A21 [[1 2 3 4 5]
         [1 2 3 4 5]]}]]
=> (view (sum B))
[7 14 21 28 35 42 49 56 63 70]
Size -> 1 x 10
=> (sum B "rows")
[[55 55 55 55 55 55 55]]