Indexing function returns (if found) the index of a scalar element in a kigubkur^© matrix (or block). Note that the index follows kigubkur^© indexing strategy; rows indices follow 1, …, m and column indices follow 1, …, n. Thus, index starts from 1 and NOT from 0.

(require '[kigubkur.dig [index :refer [findindex]]])

Examples

Index of an element in a vector

This returns the index such that

return	condition
nil	does not contain the scalar
s, a natural number	DEFAULT (contains the scalar)
[s1 s2 ... sk], a clojure vector of natural numbers	with optional argument "all" (contains multiple)

=> (def r [[4 3 2 4 0 2 1]])
=> (def c [[4][3][2][4][0][2][1]])
=> (view r)
[4 3 2 4 0 2 1]
Order -> 1 x 7
=> (view c)
[4]
[3]
[2]
[4]
[0]
[2]
[1]
Order -> 7 x 1

If the vector contains a specific number (element)

=> (findindex r 0)
5
=> (findindex c 2)
3

returns a natural number representing position in respective vector (row or column). Note that by default the function returns the first position found. To get all the positions insert the additional argument "all"

=> (findindex c 2 "all")
[3 6]

Finally, if the vector does not contain the scalar the function returns a nil

=> (findindex r 10)
nil

Index of an element in a matrix

Returns the index as

return	condition
nil	does not contain the scalar
[i j] such that i, j ∈ ℕ	DEFAULT (contains the scalar)
[[i1 j1] [i2 j2] ... [ik jk]]	with optional argument "all" (contains multiple)

=> (def M [[0 5 1 0] [2 3 9 5] [9 1 7 0]])
=> (view M)
[0 5 1 0]
[2 3 9 5]
[9 1 7 0]
Order -> 3 x 4
=> (findindex M 10)
nil
=> (findindex M 2)
[2 1]
=> (findindex M 0)
[1 1]
=> (findindex M 0 "all")
[[1 1] [1 4] [3 4]]

Index of an element in a block

Returns the index as

return	condition
nil	does not contain the scalar
[{:Apq [ip jq]} [i j]] such that p, q, ip, jq, i, j ∈ ℕ	DEFAULT (contains the scalar)
[{:Aab [ia jb] ... :Apq [ip jq]} [[i1 j1] [i2 j2] ... [ik jk]]]	with optional argument "all" (contains multiple)

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

=> (def L (urandi [7 10] [0 11]))
=> (view L)
[6 6 5 10 0 5 7 9 2 0]
[0 3 2 9 7 5 5 8 5 2]
[10 10 1 3 5 3 4 7 8 1]
[10 2 5 2 8 4 7 1 2 6]
[8 4 8 7 2 1 4 4 1 2]
[2 4 3 3 5 10 9 3 3 7]
[9 2 7 2 9 7 5 3 8 1]
Order -> 7 x 10
=> (def B (block L 5))
=> (pprint B)
[[{:A11 [[6 6 5 10 0]
         [0 3 2 9 7]
         [10 10 1 3 5]
         [10 2 5 2 8]
         [8 4 8 7 2]],
   :A12 [[5 7 9 2 0]
         [5 5 8 5 2]
         [3 4 7 8 1]
         [4 7 1 2 6]
         [1 4 4 1 2]]}]
 [{:A22 [[10 9 3 3 7]
         [7 5 3 8 1]],
   :A21 [[2 4 3 3 5]
         [9 2 7 2 9]]}]]
=> (findindex B 100)
nil
=> (findindex B 1)
[{:A22 [2 5], :A11 [3 3], :A12 [3 5]} [3 3]]
=> (findindex B 1 "all")
[{:A22 [[2 5]], :A11 [[3 3]], :A12 [[3 5] [4 3] [5 1] [5 4]]} [[3 3] [3 10] [4 8] [5 6] [5 9] [7 10]]]