2008-04-15 Ex 2.37 SICP (define (matrix-*-vector m v) (map (lambda (x) (dot-product x v) m)) (define (transpose mat) (accumulate-n cons nil mat)) (define (matrix-*-matrix m n) (let ((cols (transpose n))) (map (lambda (x) (map (lambda (y) (dot-product x y)) cols)) m)))