;; IDENTITY-4-BY-4
;; By Peter Reidy
;; Filed as {ERIS}<LISPCORE>TEST>DISPLAY>MATMULT>IDENTITY-4-BY-4.TEST
;; Syntax: (IDENTITY-4-BY-4 &optional RESULT)
;; Function description: returns a 4-by-4 identity matrix - i.e. one in which every (N,N) element is 1.0 and every other is 0.0.  If RESULT is supplied and is a 4-by-4 matrix of element-type single-float, the result is returned there. 
;; Arguments:
;;	RESULT - a 4-by-4 matrix of element-type single-float
;;
(do-test-group make-homogeneous-n-by-4-group
	:before
	(progn
		(il:load? '{eris}<lispcore>test>display>matmult>matmult-test.source)
		(test-setq non-ident (il:make-homogeneous-4-by-4 :a00 22.77 :a10 pi))
	)
;;
	(do-test identity-4-by-4-simple-case
		(and
			(idtest (il:identity-4-by-4) 4)
			(not (idtest (il:identity-3-BY-3) 4))
		)
	)
;;
	(do-test n-by-4-with-result
		(and
			(not (idtest non-ident 4))  ; before
			(il:identity-4-by-4 non-ident)
			(idtest non-ident 4)  ; after
		)
	)
)
END