Am a beginner to Scheme a dialect of Lisp, am trying to implement a function sum-vector that takes two vectors of numbers as arguments and returns a vector with the sum of the corresponding elements of the input vectors.
I have tried the following code but i can't figure out how to sum two vectors with different lengths. Here is my current code
#lang scheme
(define sum-vector
(lambda (vec-1 vec-2)
(let* ((len (vector-length vec-1))
(result (make-vector len)))
(do ((index 0 (+ index 1)))
((= index len) result)
(vector-set! result index
(+ (vector-ref vec-1 index)
(vector-ref vec-2 index)))))))
(sum-vector (vector 4 6 8 3) (vector 5 6 7))
When i run the above code it works perfectly for vectors with same lengths e.g (sum-vector (vector 4 6 8) (vector 5 6 7)) returns #(9 12 15) I want it to work similarly for different lengths e.g (sum-vector (vector 4 6 8 3) (vector 5 6 7)) should return #(9 11 15 3) but i can't figure out the logic for doing that.
One possible solution is to append zeros to each vector to make their lengths equal and then use vector-map:
(define (zero-vector len)
(make-vector len 0))
(define (append-zeros vec max-len)
(vector-append vec (zero-vector (- max-len (vector-length vec)))))
(define (sum-vector v1 v2)
(let ((max-len (max (vector-length v1)
(vector-length v2))))
(vector-map +
(append-zeros v1 max-len)
(append-zeros v2 max-len))))
Tests:
> (sum-vector (vector 1 2 3) (vector 1 2 3 4 5 6))
'#(2 4 6 4 5 6)
> (sum-vector (vector) (vector 1 2 3 4 5 6 7 8))
'#(1 2 3 4 5 6 7 8)