(3determinant) ( matrix-seq -- 3det )

Vocabulary

math.matrices.extras.private

Inputs

matrix-seq

an object

Outputs

3det

an object

Definition

USING: arrays kernel math.matrices math.vectors sequences ;

IN: math.matrices.extras.private

:: (3determinant) ( matrix-seq -- 3det )
    matrix-seq first first3 :> ( a b c ) matrix-seq rest
    transpose
    [ rest ] [ [ first ] [ third ] bi 2array ] [ 1 head* ] tri
    3array [ (2determinant) ] map { a b c } t alternating-sign
    v* sum ;